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1. however there does not seem to be any way of preventing scrolling of the entire screen after responding to an INPUT statement in line 25 As a result the only safe way of getting user response in line 25 is by means of the INKEY function which does not require use of the ENTER key Of course this means vou are restricted to single keystroke responses Another apparent difference between the two BASIC implementations is that in GW BASIC CLS appears to affect the entire physical screen regardless of any VIEW that may be current In BASICA on the other hand the effect of CLS is limited to the then current VIEW Downloaded from www timcart com Urban Data Management Software 177 Table I The structure and size of UDMS 1 01 Code Program name Description No of lines bytes MAIN Presents the main menu 57 4 000 MAINB Presents a sub menu for spatial analvsis 42 1 004 CHECK Checks that polygons are closed and correct 52 1 255 CORD Creates the basic map co ordinate file 62 1 653 NETDIST Calculates the link distances in a network 33 569 SCALE Scales co ordinates for mapping 30 1 864 SORT Sorts line segments for choropleth mapping 97 1 169 BDRY Creates polygon boundary maps 77 1 189 OVERLAY Overlays points networks on boundary maps 45 1 897 MAP Assigns values to sorted line segments 47 478 MAPOUT Creates choropleth map 147 2 407 CIRCLE Searches for points in a circle 30 901 CIRCLEI 37 640 PSEARCH Searches for points in a po
2. use of colour as well as the pan and zoom facilities make for more useful and flexible maps Second throughout the program UDMS 5 is designed to cater to less expert but more demanding users than were earlier versions of UDMS Thus for example users are advised of the capacities and limitations of each program Unusual or heuristic algorithms are explained on the screen so that users can assess their suitability for the specific applications intended Results are carefully summarised and annotated so that hard copy output always provides a full and complete record In short UDMS 5 has evolved into what is at least from the planning point of view a more and more sophisticated program in which mapping and quantitative techniques reinforce rather than compete with each other Another significant impact of the microcomputer which is reflected in the evolution of UDMS has to do with the demand for training that it has provoked It is tempting to see this demand primarily in terms of computer skills but that can be quite misleading Of course there are many planners who still need to learn more about how to use computers as such But it is just as important for planners to learn or re learn the kind of techniques that computers can facilitate because without the help of computers few planners will have been using such techniques For example many planners learned about regression techniques when they were at school yet how ma
3. 51 2 216 224 Spring 1985 Levine N The Construction of a Population Analysis Program Using a Microcomputer Spreadsheet APA Journal 51 4 496 511 Autumn 1985 Microcomputer Software Packages Produced by the Organizations of the United Nations System Supplement to ACCIS Newsletter 4 3 September 1986 Minieka E Optimization Algorithms for Networks and Graphs Marcel Dekker New York 1978 Morgan C L and Waite M 8086 8088 16 Bit Microprocessor Primer BYTE McGraw Hill Peterborough 1982 Norton P Inside the IBM Personal Computer Revised and enlarged edition Brady New York 1986 Norton P Programmer s Guide to the IBM PC Microsoft Bellevue 1985 Oppenheim N Applied Models in Urban and Regional Analysis Prentice Hall Englewood Cliffs 1980 Osborne A Eubanks G Jr and McNiff M CBASIC User Guide Osborne McGraw Hill Berkeley 1981 Ottensmann J R BASIC Microcomputer Programs for Urban Analysis and Planning Chapman amp Hall New York 1985 Ottensmann J Microcomputers in Applied Settings the Example of Urban Planning Sociological Methods in Research 9 493 501 1983 Ottensmann J Using Personal Computers in Public Agencies John Wiley New York 1985 Parsly J Using ROM Characters PC Tech Journal p 47 August 1986 Robinson V B and Coiner J C Characteristics and Diffusion of a Microcomputer Geoprocessing System the Urban Data Management Softwa
4. UDMS used seven more types of datafiles which are no longer necessary in UDMS 5 These are LST a modified version of REG XYA containing area data ROP VAR containing data for the gravity model CTR PTS and CTRM PTS containing data for optimum location analysis NCF containing data on node constraints for optimum location in a network NSF containing data on a subset of an existing network and RGR containing data for regression analysis For more details see the file UDMSFILE DOC on the distribution disk version 5 2 only UDMS datafiles generally consist of three distinct parts There is usually a header containing one or two file parameters such as the number of data elements which are used to facilitate reading the file Of course datafiles can be read without this information e g by using WHILE NOT EOF WEND but it is generally preferable to use a fixed length loop Moreover in cases where UDMS needs only the total number of data elements and not their details Downloaded from www timcart com Urban Data Management Software 183 having the information at the top of the file obviates the need to read the entire file The main part of a datafile consists of the data themselves Some of the datafiles include a sequential identification number for each data element Although this number is not used outside the file itself it has been retained partly to preserve continuity with earlier versions of U
5. a network but users are here faced with a different kind of problem Because of the limits imposed by the structure of the network we can be confident that the optimum location found by the program is indeed optimum but only if there is an optimum location at all The cause of this kind of problem is what is called directional connectivity Every network has to be physically connected in the sense that every node has to be linked directly or indirectly to every other node In fact network creation routines built into UDMS 5 do not permit the creation of networks that are physically unconnected However when a network is created one of the par ameters of each link is its direction Thus some links in a network may be uni directional and not permit movement in both directions In other words although every node in a network must be physically connected to every other node movement may not actually be possible from every node to every other node Thus physical connectivity may not always mean directional con nectivity 7 Where there is not universal directional connectivity within a network the concept of optimum location becomes problematical can any location on a network be said to be optimum if it is not accessible to all nodes Certainly any calculation of total or mean distances to an optimum location when some of the distances are effectively infinite is going to be misleading Unlike earlier versions UDMS 5 recognises al
6. file as simple and uncomplicated as possible it consists of nothing more than a sequence of two data elements for each point on the boundary of the map namely its X co ordinate and its Y co ordinate No other data are required in the DAT file All the other data required by UDMS the file header and footer and sequential point identification numbers are added by UDMS when it converts the DAT file to a corresponding COO file The latter then becomes the basic map file for the rest of the program the former has no further purpose in UDMS and can be erased if desired All other datafiles can be created and when appropriate edited from within UDMS In each case the process is closely prompted and error trapped by UDMS in order to guard as much as possible against mistakes and omissions in data entry Preliminary experience with this approach in workshop settings has shown a dramatic reduction in the amount of time required by trainees to create data files The socio technical impact of microcomputer development and use has once again been such as to lead to more integration and standardisation in the structure of UDMS This in turn helps make its user interface easier to understand and smoother to operate The next section of this paper examines how improvements in the program and data structure of the program have led to enhanced performance THE MAIN FUNCTIONS OF UDMS UDMS performs four basic functions The
7. it is important to remember that a map is only a representation of certain underlying data and that a map may reflect numerous approximations interpolations and guesses However because paper maps are relatively inflexible and labour intensive artifacts there is a tendency for maps to take on a reality of their own As a result planning sometimes is done on and with maps rather than with the underlying reality represented by those maps The widespread accessibility of microcomputers and programs similar to UDMS can help prevent this distortion The effect will not be to diminish the importance of maps in planning but it should change the role they play Because computers can make mapping so much more flexible and so much less labour intensive they allow and even encourage planners to work more directly with the data forming the basis of the maps The result is that maps should assume a more illustrative and less substantive position in planning than the one they sometimes seem to occupy Similarly some of the traditional emphasis in planning education given to cartographic techniques can be expected to give way to training in more general analytical techniques These tendencies are reflected in two important enhancements to UDMS 5 compared to earlier versions First of all the mapping in UDMS S is superior to that of earlier versions The 6 See Cartwright 1979 Downloaded from www timcart com 190 T J Cartwright et al
8. less restrictive than it was The main reason is that the aim of the agreement has changed from one of trying to control distribution to one of trying to encourage it consistent only with preservation of copyright and protection against liability Thus UDMS can now be copied and distributed almost without restriction The only critical conditions are that all copies that are made must include on the disk a copy of the licence agreement and that no use can be made This assessment differs from that reached by Robinson and Coiner 1986 which seems to be based only on the period in which they were directly associated with development of UDMS i e from 1980 to 1983 Essentially programs written in a compiled language are converted to code understandable by the computer prior to execution in fact it is this compiled version of the program that is then executed not the original code written by the programmer Programs written in an interpreted language on the other hand are converted to machine code by the computer during execution no separate executable version of the program is maintained For UDMS 5 3 we used the TurboBASIC compiler from Borland International Downloaded from www timcart com Urban Data Management Software 175 of the package until that agreement has been signed by a responsible person and forwarded to Habitat in Nairobi In this way the growth and development of UDMS over the last 8 years reflects much of the
9. relatively little cost in terms of time for learning or money for equipment THE ORIGIN AND EVOLUTION OF UDMS The original version of UDMS was prepared for UNCHS Habitat in 1980 Version 1 00 was written under contract by Dr Vincent Robinson and Ms Wanna Chin then of the Department of Geography Hunter College New York Technical assistance was provided by Dr Jerry Coiner then also in the Department of Geography at Hunter College and subsequently Special Adviser to Habitat The project was co ordinated by Dr Ignacio Armillas a staff member of UNCHS Habitat in Nairobi UDMS 1 00 was written in CBASIC a pseudo compiled BASIC on a Vector MZ microcomputer using 5 4 inch disks with 16 hard sectors per track Micropolis format A preliminary User s Manual labelled Version 0 98 and bound in a green cover was also released before the end of 1980 In early 1981 Robinson and Chin completed a more generic version of the package Version 1 01 designed to run on any CP M based system capable of running CBASIC Over the next several years Version 1 01 was made available in appropriate format for many different microcomputers including various models of Altos Compupro Cromemco Dynabyte Godbout IMS Morrow Northstar Ohio Scientific Osborne SD Systems TEI Tandy TRS 80 and Zenith UDMS was also installed on several minicomputer systems including a Wang 2200VP in Sri Lanka and an NCR 9000 in Cyprus at one poi
10. to electricity generation in Norway 171 Downloaded from www timcart com 172 T J Cartwright et al in developing countries As such UDMS has always had something of a dual nature on the one hand UDMS is meant to be sophisticated enough for planners to be able to use it in real professional situations on the other hand UDMS is meant to be simple enough to be accessible to as many users as possible In practice this has helped create a number of important objectives for UDMS 1 UDMS should be able to run on as wide a variety of microcomputer equipment as possible 2 UDMS should be able to work without the need for specialised peripherals such as digitisers or plotters yet still be able to take advantage of such devices when they are available 3 UDMS should be friendly enough for planners with no specialised knowledge of computers to be able to use and understand without difficulty 4 UDMS should be suitable for use in both operational and training settings so its architecture should be open and accessible to anyone interested in examining it In short the purpose of UDMS has always had both a technical and a social dimension On the one hand UDMS is meant to push microcomputer technology to its limits in order to show how much can be done with it On the other hand UDMS is also meant to demonstrate that these new capacities can have an important social impact for they can be made available to any planner at
11. written in a less popular and less widely understood programming language than BASIC The decision to move from compiled to interpreted BASIC was based on a number of factors One advantage of CBASIC is that its run time module This is not meant to be an authoritative interpretation of the Licence Agreement the full text of which is contained in the file UDMSFORM DOC on the distribution disk and should be consulted prior to any use of the package See Osborne et al 1981 HAB 12 4 L Downloaded from www timcart com 176 T J Cartwright et al CRUN2 can be distributed freely without copyright violation however the almost universal bundling of Microsoft BASIC with 16 bit microcomputers has made this advantage academic Another advantage of CBASIC is its speed of execution however this argument too has become less persuasive since compilers for interpreted versions of BASIC have been developed On the other hand CBASIC even in its CB 86 version has nothing like the graphics capabilities of Microsoft BASIC In any case much of the apparent slowness of UDMS I was due to slow disk access rather than slow program execution The best fix for this kind of problem lies not so much in the choice of programming language as in use of a hard disk and or a RAM disk For these and other reasons UNCHS decided te convert UDMS from CBASIC to interpreted BASIC Specifically UDMS 5 was written for version 2 0 and higher of Micros
12. 1 99 contain a summary of what the program does and what data files it needs input and creates output Lines 100 999 contain global initialisation statements and sub routines these lines appear in each of the modules in the interpreted version 5 2 but only once in the compiled version 5 3 Their contents include code for displaying and selecting options from the main menu clearing the screen and formatting displays dumping the contents of the screen to the printer setting the default disk drive and filename for data files and accessing the various pages of the disk manual The adherence of all modules to these common routines as well as the improved structure of the whole program obviate the need to define and pass any COMMON variables from one program to another as had been required in UDMS 1 This was a real advantage when it came to compiling the programs Since compilers of interpreted BASIC do not all treat the COMMON command and its parameters in the same way it is better to do without that command whenever possible Lines 1000 1999 prefixed by a digit from 1 to 5 in the compiled version to represent each of the five modules contain the main menu s for each module the corresponding assignment statements ON GOTO and local subroutines that are common to several parts of the module The major substantive sections of each module begin at lines 2000 3000 4000 etc suitably prefixed by a digit from 1 to 5 for each modu
13. DMS and partly because having the numbers facilitates inspection and editing of the file Earlier versions of UDMS made two other stipulations regarding data entry that have now been dropped In some cases data had to be entered starting at a particular maximum value and or proceeding in counter clockwise order Now UDMS 5 requires only that data be entered in sequence Second earlier versions required that some sequences of data elements be closed by means of repeating the first data element UDMS 5 provides its own closing by means of software The third part of a UDMS datafile is a footer containing details of the grid scale used in the map e g 1 5 000 and the scale units themselves e g kilometres or miles This footer is added only to some of the files but could easily be added to others as required Earlier versions of UDMS also required that some of the datafiles notably the COO and REG files contain data pertaining to a so called false region The false region was the region formed by the outer boundary of the map and a rectangle drawn around it scaled to suit output to a simple line printer Now that all printer output is based on screen dumps and dot matrix printers the false region is no longer required The false region was also used in one or two other routines e g in one of the spatial search routines but these algorithms have also been changed Consequently none of the dataf
14. HABITAT INTL Vol 12 No 4 pp 171 193 1988 0197 3975 88 3 00 0 00 Printed in Great Britain 1989 Pergamon Press ple Urban Data Management Software The Growth and Development of Microcomputer Software for Planning T J CARTWRIGHT 7 M R BROWNi and H V SEAFORTH York University Toronto Canada and UN Centre for Human Settlements Kenya For a piece of microcomputer software Urban Data Management Software UDMS has quite a long history it is more than 8 years old and has been through at least 5 major revisions Few other programs with such a venerable history programs such as Wordstar dBase or Visicalc have quite such a direct connection with planning as UDMS As such UDMS provides a good barometer of both the technical develop ments that have taken place during this period and the social impact which microcomputers are starting to have on the planning profession in both industrialised and developing countries The purpose of this paper is to describe how UDMS has evolved during the formative years of the microcomputer revolution in order to illustrate on the one hand some of the factors involved in writing planning software and on the other hand some of the social and technical impacts which the microcomputer revolution is having on the planning profession itself Urban Data Management Software UDMS is a polygon based geographic information system UDMS can store analyse and display data related to poi
15. KAKAKKAKAKKAKKAS BOSSES EEE E KK KK KKK KKKKKA KE RKKK FSSSS ESSE SAKA KKK AKA KKK KAA KEKE HOR IORI KICK KK RK KKK KKK HK HOI RK KK IKK KKK EKA K E KKK KKK KKK KAKA K ER AK KAA KK KE KKK KKK KKK KKK AOA ARK AOAO AO OK K OAOA AOKK K LEGEND e e WOULD YOU LIKE ANOTHER COPY N Fig 1 Unretouched map showing average income in three regions drawn using UDMS 1 Source UDMS User s Manual Version 1 03 p 76 UDMS I was unable to map both variables and networks as shown in next figure DOS program GRAPHICS COM The result is that all printouts can be previewed on the screen and they all have a consistent format and size 25 lines by 80 columns Also UDMS S5 automatically stamps each printout with the current date and time read from the system clock Moreover UDMS 5 contains code that enables it to adjust to the parameters of its host hardware If there is a colour graphics adapter CGA in the system for example UDMS 5 detects it without asking the user and uses colour and medium high resolution graphics as and when they are appropriate If not This method is possible thanks to Interrupt 5 in the ROM BIOS of IBM and compatible microcomputers see Norton 1985 The easiest way to take advantage of this service is to tell users to press SHIFT and the PrtSc key whenever they want a printout However this has the disadvantage that everything on the screen including the instruction to use the PrtSc k
16. Moreover there is relatively little incentive to try In the same way manufacturers of software have discovered that copy protection no matter how ingenious and transparent they have been able to make it does not pay Anything that come between users and accessibility detracts from the value of hardware and software So here too UDMS 5 exhibits a different philosophy from that of earlier versions UNCHS Habitat now actively encourages distribution of and access to its software The Licence Agreement is less restrictive and users are encouraged subject to very minimal restrictions to provide copies of the package to other interested parties inside and outside their own organisation In fact to make distribution as easy as possible the entire UDMS 5 package including disk manual Licence Agreement and preliminary startup instruc tions is included on the distribution disk In retrospect UDMS has evolved in response to its environment Originally conceived primarily as a demonstration and training package UDMS has in fact evolved into a practical tool as well UDMS began life in a laboratory workshop context where computers have traditionally been used Later when the ordinary planner as user began to emerge UDMS found itself installed in various operational settings This imposed new demands on the package which led to its eventual rewriting as UDMS S In this way UDMS reflected the broader trends of the microcomputer revolu
17. cessible to naive users and even novice programmers who want to customise or enhance its various modules and routines Furthermore in every part of UDMS 5 the programs deal with the user in an open and friendly manner carefully explaining and prompting at every step In this way the user is encouraged to understand exactly what the computer is doing so as to be better able to evaluate the answer that the computer provides Thus while UDMS S5 tries to hide as much of its computer face from the user as possible it tries to do the opposite with its planning face No one can learn to use UDMS 5 without learning something about planning as well A third significant way in which UDMS 5 reflects the changing role of microcomputers is in terms of accessibility If there is one major lesson to be derived from the experience of most organisations in implementing micro computers it is that If you don t have it you won t use it Learning to use a Downloaded from www timcart com Urban Data Management Software 191 microcomputer takes skill but it is a purely functional kind of skill It has little aesthetic or scientific value Memorising the commands of Wordstar for example is about as valuable as memorising telephone numbers If you use them every day learning them is easy and useful If not or even if you cannot use them regularly once you have learned them these kinds of skills are hard to acquire and retain
18. d Nations Fund for Population Activity UNFPA in Mexico City in February 1986 However neither the official nor the unofficial CB 86 version of UDMS was more than just a translation of the original version The programs themselves were not changed and thus still bore the mark of having been written for the old eight bit environment The problem was that in another sense converting UDMS to the sixteen bit environment of the IBM PC and compatible was not so simple For the new environment provided new powers and capacities more memory higher speed and video graphics that were beyond the reach of CP M machines and even of CBASIC So although it could be made to run on sixteen bit machines UDMS would clearly not be able to take advantage of the new environment without a major rewriting Consequently between 1983 and the end of 1985 at least three new versions of UDMS appeared all designed to capitalise on the sixteen bit machines These three versions which became known as UDMS 2 UDMS 3 and UDMS 4 respectively were produced by Dr Richard Langendorf and Katia von Lignau at the Department of Urban and Regional Planning University of Miami at Coral Gables USA 3There are many sources for technical details of the 16 bit environment e g Morgan and Waite 1982 for details of the microprocessor and Norton 1986 for details of what computers based on that chip can do Osborne et al 1981 is the standard source on CBASIC for microco
19. de more user friendly and partly because new features were added Moreover one of the key objectives in the design of UDMS has always been to produce a program that could run on a minimum system The original version of UDMS was written for computers with only 48 Kb of RAM By the time CP M and the CBASIC run time module CRUN2 are loaded this leaves only just over 40 Kb the exact amount may vary from one microcomputer to another in the transient program area TPA for loading and executing programs including storing all the constants variables and arrays used by the program Keeping programs small is thus a matter of critical importance although it could be debated how much of the fragmentation of UDMS 1 see Table 1 was dictated by hardware limitations and how much was in fact a matter of programming style In any case the move to the sixteen bit DOS environment opened up a variety of new possibilities for UDMS rewrite it for CBASIC in the new environment rewrite it in interpreted BASIC or rewrite it in another programming language altogether PASCAL and C being the obvious choices In fact this last option was discarded almost immediately Quite apart from not feeling that the benefits would justify the costs involved in changing languages UNCHS had always wanted UDMS to have an important demonstration effect as well as a purely operational role Clearly the didactic value of UDMS would be diminished if it were to be
20. e ROM BIOS for which there was no equivalent in the eight bit CP M environment Essentially VIEW sets the size of the screen or viewport to be used for the display the default setting is the entire screen WINDOW on the other hand determines the scale to be used for the display the default condition is that the window co ordinates or world co ordinates as Microsoft and IBM prefer to call them exactly match the physical screen co ordinates The combined effect of these commands is to allow the programmer to define a VIEW inside the border of the map and by changing the co ordinates of the WINDOW mapped into that VIEW appear to be moving the map around in the VIEW or to be enlarging or reducing it There is no limit to how far a map can be panned and zoomed beyond the practical one that all trace of the map will eventually disappear from the screen if it is moved either too close or too far away The combination of VIEW and WINDOW works very well and effectively but it did lead to several other technical difficulties Of course the program had to arrange to store the initial WINDOW co ordinates so that the original map could be restored at anv time Second it was necessary to decide whether Labelling regions and points on a graphics screen is in fact quite difficult to do If vou PRINT a character to the screen in medium resolution graphics mode it appears twice the size of characters in te
21. essible as possible both capabilities are provided UDMS 5 is equipped to determine whether its host system is capable of high resolution If it is then the program plots in high resolution if not the program plots in low resolution 19 The oniy other approach we considered was to use the principle of the BASIC PAINT command discussed above This could be done either by simulating the operation of the command or by actually drawing a map in memory e g using an inactive page of video RAM and PAINTing from the point If the colour of the point matched the colour of the region to be searched again using the special regional PAINT points discussed previously then the point must lie in the region if not the point must lie outside the region In the end this method was not used Downloaded from www timcart com 186 T J Cartwright et al In the regression part of the program the major change has been to replace the bi variate model used in earlier versions of UDMS with a multi variate model in UDMS S5 One of the major constraints in this part of the program was the need to present compact screen displays suitable for dumping to a printer Earlier versions of UDMS had printed their results with scant regard for line spacing or page layout With UDMS 5 however the idea was to write so far as possible for a 24 line page and to keep the number of display pages to a minimum For this reason the maximum number of independent
22. exactly equalled the radius would lie on the circumference of the circle It is also quite straightforward to allow for a search of more than one circle at once even if the circles overlap For example you can use the same algorithm to search for points within a set of linked nodes and their respective areas of influence But it is quite another matter to provide a simple algorithm for searching for points in a polygon of indeterminate shape Historically UDMS has confined itself to searching for points within one of the map regions rather than any user defined polygon Nevertheless map regions can assume any shape at all so the algorithm in the program has to be capable of dealing with any kind of polygon The general principle of searching for a point in a polygon is to project a straight line from the point to either the X axis or the Y axis and count the number of times that line intersects the boundary of the area to be searched If the line intersects the boundary an odd number of times the point is presumed to lie within the search area if the line intersects the boundary an even number of times the point is presumed to lie outside the search area However this algorithm works only if it is supported by a series of tests to detect and allow for a number of special cases where the point is at a vertex or on the boundary of the search area or where the line projected from the point passes through a vertex or runs along the boundary o
23. ey itself is included in the printout There are several ways to obtain the same effect under program control which means that the program can ask whether a printout is desired and then if so erase the query before proceeding with the screen dump In compiled versions of BASIC you can just call the appropriate routine e g CALL INTERRUPT 5 in Turbo BASIC In interpreted versions of BASIC things are a bit more complicated According to several sources the effect of SHIFT PrtSC can be obtained by storing the value 51973 8 to a single precision variable say X and then using the command CALL VARPTR X The effect apparently derives from the manner and location in which BASIC stores this particular value However we were unable to make this routine work consistently in UDMS 5 So we decided to rely instead on the following assembly language routine derived from an example given in the IBM BASIC Reference Manual Appendix B page B 9 DIM PRT 3 FOR I 1 TO 3 READ PRT I NEXTI DATA amp HCDS55 amp H5D05 amp H90CB A VARPTR PRT 1 CALL A 13This approach is exemplified in Rosenblum and Jacobs 1986 Note that UDMS 5 does not support the Hercules monochrome standard 720 x 348 pixels Downloaded from www timcart com 180 T J Cartwright et al DADS AND POPULATION 866825 19 G3 ROADS AND POPULATION Variable Legend INCOME Fig 2 Unretouched map showing average income and road network in three regions drawn
24. f the search area from both inside and outside the search area Ciearly these tests complicate an otherwise elegant algorithm This basic algorithm has been used in all versions of UDMS However prior to version 5 UDMS made no allowance for the possibility of special cases like those described above Consequently results were sometimes wrong In UDMS S routines were added to test and if necessary correct for each of the special cases At the same time other improvements were made to make this module of the program more user friendly by providing for 1 more standardised prompts and displays and 2 faster repeat testing for the location of a given point Mulriple regression and gravity model From the programming point of view the chief source of difficulty underlying this part of the program is the very wide range of values that the results can take In the end UDMS 5 reflects the same compromise as earlier versions of the program results are displayed in exponential notation Essentially this means sacrificing readability in exchange for the flexibility of being able to get all the results on a single screen This makes it easier to absorb and compare the results In the case of graphical displays the chief question was whether to use low resolution graphics or text mode to make the results available on micro computers without a colour graphics adapter or high resolution graphics In the end to make the package as widely acc
25. few more features was released in October 1986 The following year this version was translated into Spanish by Harry Koppel a planning consultant based in Bogota and used in a national workshop in Santiago Chile Finally with Version 5 3 released in August 1987 UDMS has come full circle the program is once again in compiled form This has at least three important advantages and no real disadvantages 1 Loading time is reduced because the whole UDMS program can be held in memory at once Microsoft BASIC allows users only 64 Kb of memory so large programs like UDMS have to be broken up into less than 64 Kb pieces and loaded in and out of memory as required Modern BASIC compilers allow users to work with all available memory so the entire program can be loaded into memory once and for all 2 The program runs much faster because interpretation into machine code is done before not during run time 3 Modern BASIC compilers also make use of mathematical coprocessors if installed thereby further increasing program execution speed Version 5 3 also fixes some bugs in previous versions and adds a few new features Copies of UDMS S5 have been distributed to hundreds of individuals and agencies in about 50 countries around the world With UDMS 5 Habitat also revised its distribution policy While Habitat still maintains full copyright on all versions of UDMS and requires users to sign a licence agreement this agreement is now
26. general character of the microcomputer revolution UDMS has clearly developed with the technology both in terms of the standards it has embraced and the features it has offered UDMS has grown incrementally along with technological developments and the increased sophistication of users UDMS has found its way into an extraordinary number of situations and countries and has been run on a great variety of systems with varying degrees of success of course Finally and perhaps most significant of all UDMS has consistently become more and more user friendly both in terms of the interface it presents to users and the accessibility of its code In the next three sections of this paper we shall examine these points in more detail by examining the nature of the UDMS package how its data files are structured and what the program actually does THE NATURE AND STRUCTURE OF UDMS Version 1 01 consisted of 30 separate programs and this same structure was maintained more or less intact subject to some consolidation in UDMS 4 through all subsequent versions prior to UDMS S Table 1 provides a detailed breakdown of the nature and size of the original version In this version 1 01 UDMS added up to less than 50 Kb of source code and about 80 Kb of intermediate or object code in CBASIC When UDMS was converted to interpreted BASIC in the sixteen bit DOS environment the size of the program promptly doubled partly because existing features were ma
27. ghtly revised version of UDMS Version 1 03 was released The new version was supported by extensive documentation bound this time in orange covers including a User s Manual Program Listing and an Instructor s Manual Among those contributing to these manuals was Professor Jose Galbinski of the Departamento Urbanismo Universidade de Brasilia Brazil Later in 1983 the first French edition of UDMS Version 1 03 was also released Just as UDMS hit its stride in the eight bit CP M environment however a new standard was emerging This new standard was based on the sixteen bit Intel 8088 8086 microprocessor and the Microsoft DOS operating system both of which are embodied in the IBM PC and its now numerous compatible clones In one sense it was easy enough to convert UDMS to run in the new environment UDMS had deliberately been written in a highly portable language CBASIC Thus as soon as a suitable compiler for CBASIC became available in the new sixteen bit environment UDMS could be run on IBM and IBM compatible microcomputers Indeed by early 1984 Robinson and Coiner then working on their own reportedly had a CP M 86 CBASIC CB 86 version of UDMS running A year later UNCHS Habitat released its own CB 86 version of UDMS prepared by Herbert Seaforth and others This version which became known as version 1 04 was later translated into Spanish by Ignacio Armillas and presented at a conference organised by the Unite
28. gional co ordinates file consists of sequence of points that define each region VAR Regional variables file consists of variable names followed by corresponding variable values by regions PTn Points co ordinates file where n is any legal character except C which is reserved for the regional centroids consists of co ordinates of any user defined set of points These files were called PTS and CNT respectively in earlier versions of UDMS PNT Paint co ordinates file consists of co ordinates of points one for each region that are physically located inside a region This file was called CNT PTS in some earlier versions of UDMS WPn Points weights file where nn is the last character of an associated points file consists of a set of weights corresponding to each of the points in the associated points file This file was called PWF in earlier versions of UDMS 1Cn Interaction between centroids file where a is any legal character consists of any user defined set of interactions or flows between regional centroids This file was called ITR in earlier versions of UDMS NWn Network nodes co ordinates file where n is any legal character consists of the co ordinates of any user defined set of network nodes This file was called NOD in earlier versions of UDMS Lom Links definition file where m is any legal character and n is the last character of an associated ne
29. hics and colour For a program which has important mapping functions this was an opportunity of major proportions Thus on a system that has the appropriate hardware a colour graphics adapter or CGA and composite monochrome or colour RGB monitor the mapping capabilities of UDMS 5 are far superior to those in earlier versions Use of medium resolution graphics gives 64 000 plotting points 320 by 200 instead of the 1 920 80 by 24 points available to earlier versions of UDMS This means that the resolution of maps in UDMS 5 is more than thirty times greater than that of earlier versions Similarly medium resolution permits the use of four different colours on a colour RGB monitor or four different shades of a single colour on composite monochrome or LCD gas plasma monitors All of these displays can be further enhanced by creating tiles to add distinct patterns to the colours or shades How faithfully all these screen enhancements can be transferred to 10 Procedures for creating tiles for the PAINT command are described in various BASIC reference manuals Downloaded from www timcart com 178 T J Cartwright et al Table 2 The structure and size of UDMS 5 2 ASCII Code Program name Description bytes bytes UDMS Introduction to and one time initialisation of the 14 464 12 779 package UDMS1 File creation routines for boundary map 42 496 35 935 regions variables points points weights net work
30. iles now contains any references to a false region In earlier versions of UDMS datafile preparation was done largely outside the UDMS environment Of the 20 different datafiles used by the program eleven of them had to be created by the user using a text editor or word processing program This meant that the user had to come to terms with the structure of each of these files Accordingly the original User s Manual contained detailed instructions on the use of ED the text editor typically associated with CP M and on the structure of the datafiles themselves This approach clearly had some desirable effects It contributed to indeed demanded a deeper understanding on the part of users as to how UDMS actually worked Any user who created the input files would know exactly what data were being used for what purposes and would therefore be better able to appreciate the meaning and reliability of the results derived from those data Similarly an intimate knowledge of the structure of the datafiles means that a user can more easily make minor repairs in or additions to the datafiles However creating datafiles outside UDMS where there is virtually no effective error trapping led in practice to extensive problems and delays particularly when it came to training beginners in the use of UDMS Even with the detailed examples in the User s Manual it sometimes took literally days during training workshops for trainees to prepare en
31. ir speed we would never dream of using them for anything gt VIEW and WINDOW are easily confused indeed the terms might better have been interchanged So it may help to think of VIEW as being like the size of a porthole you are peering through and WINDOW as being the property of the glass in the porthole that either magnifies or reduces the image of what you see Note that you should always use VIEW in conjunction with WINDOW if you plan to PAINT parts of the map For without the boundaries of a VIEW you run the risk of PAINT leaking out around the edges of the map if you have any gaps between the map and any map border or title that you may be using Downloaded from www timcart com Urban Data Management Software 189 a user would feel more comfortable panning literally or intuitively in the first case panning to the left would move the map to the right whereas intuitively a user might expect the opposite In the end UDMS adopted the intuitive rather than the literal approach Third grid reference lines had to pan and zoom in step with the map itself Eventually all these problems were solved and UDMS 5 now provides mapping capabilities superior to those of any of the earlier versions Few of these improvements could have occurred without the improved technology provided by the new 16 bit DOS environment Similarly the more professional quality of the results in this and other mapping programs is persuading m
32. l these difficulties and if they arise reports them to the user Here again UDMS 5 presents a smoother and more professional face to the user Thanks primarily to refinement of suitable microcomputer based algor ithms UDMS 5 is both better and easier to use than earlier versions Mapping Perhaps the most dramatic change in UDMS 5 relative to earlier versions is in terms of its maps just as the biggest qualitative change in the new 16 bit DOS environment relative to its predecessor was in its video graphics and colour capabilities Earlier versions of UDMS could provide two different kinds of maps a boundary map and a thematic map showing regional variables with the option of point and or network overlays on the boundary map In UDMS S This situation is analogous to one of the hoariest problems in operations research in which the object is to find the route of least distance for a salesman to travel to every one of a number of cities As the number of cities increases calculation of the distances along all possible routes becomes prohibitively time consuming even with a computer So more heuristic algorithms have to be found with all the uncertainty that this entails gt This may seem counter intuitive until you realise that in gravity fed hydraulic systems for example a network may be entirely inter connected in a physical sense yet water will not flow uphill from lower nodes in the network to higher ones Downloaded f
33. le Finally lines 9000 to 9999 also with a suitable prefix for each module contain error traps and error routines A consistent structure for every module in the program helped make programming and debugging much easier A consistent structure should also help make the program easier for users to understand and if they so desire to customise In short developments in technology have affected the structure and functioning of UDMS in at least four important ways from a programming point of view 1 a tighter integration of all the various parts of the package and 2 a closer fit between the software and the capabilities of the hardware and from a user s point of view 3 the addition of new features and capabilities and 4 the provision of a more user friendly interface The result is that UDMS has successfully evolved into a smoother and more sophisticated package Yet it is still capable of running on a minimum computer system UDMS DATA FILE STRUCTURE UDMS S5 uses up to 15 different types of datafiles compared to 20 in earlier versions The files are all standard flat ASCII files with individual data items delimited by commas or spaces and carriage returns Datafiles pertain to one of four basic geographic entities 1 boundaries of the map and its regions 2 regions variables and interactions 3 points including optionally their relative weights and 4 networks including nodes links dis
34. lygon 106 1 675 INTERSTN Detects intersection of polygons 184 3 316 GRID Overlays a grid on a polygon 32 2 236 CLOCK Reverses counter clockwise coding 78 769 VARSTAT Calculates variable descriptive statistics 83 375 REGEOMET Calculates region centroids area and perimeter 58 2 851 VARREGR Performs simple linear regression 133 2 458 PLOT Plots results of linear regression 132 1 496 REGRAVIT Performs gravity model calculations 61 1 166 LOCI Finds single optimum locations in a plane 76 1 559 LOCM Finds multiple optimum locations in a plane 148 2 675 NETLOC1 119 1 685 NETLOC2 Finds optimum location s in a network 104 1 407 NETLOC3 96 195 SPATH1 29 654 SPATH 2 Finds shortest paths between network nodes 77 859 SPATH3 112 1 622 Total 2 884 49 024 Average per program 96 1 634 Source UNCHS Habitat UDMS Programme Listing Version 1 01 Nairobi mimeo June 1983 According to another UNCHS Habitat publication Technical Notes No 5 the source code compiled to about 80 Kb of intermediate code description of what it does and how it works Screen layout and prompts are detailed and consistent throughout Detailed technical or background infor mation is provided for those who want it in a ten page on line disk manual that can be called from any part of the package or since it is an ordinary ASCII file printed on a printer Another objective of the move to the sixteen bit DOS environment was the opportunity to use grap
35. mputers while microcomputer programming in interpreted BASIC is discussed in numerous textbooks and other sources Downloaded from www timcart com 174 T J Cartwright et al Mehmet Icagasi then a UNCHS Habitat consultant to the Ministry of Public Works and Housing in Dubai United Arab Emirates and e UNCHS Habitat staff in Nairobi led by Herbert Seaforth All three versions were written in Microsoft interpreted BASIC Interpreted BASIC called BASIC and BASICA on IBM systems and GW BASIC and other names on compatibles is a more powerful but slower and less standardised version of BASIC than CBASIC however the development of compilers for interpreted BASIC soon justified the abandonment of CBASIC The other significant feature of these early DOS BASIC versions is that they were the product of quite extensive feedback and communication between users and authors In the end neither UDMS 2 UDMS 3 nor UDMS 4 was ever officially distributed by UNCHS Habitat For they were overtaken by a decision in Nairobi early in 1986 to release not just a conversion of UDMS 1 but a thorough revision The result was UDMS S a completely restructured and rewritten version incorporating new features new displays and new algorithms Version 5 1 was tested in August 1986 at a UNCHS Habitat inter regional workshop at the Asian Institute of Technology in Bangkok Thailand Version 5 2 which fixed a number of bugs in Version 5 1 and added a
36. n compiled form Version 5 3 consists of a single program of about 180 Kb In other words UDMS 5 capabilises on the extra memory available in the new environment to consolidate its structure Second the overall size of the package has roughly doubled In part this is due to the addition of new features and capabilities such as file creation under program control and the ability to pan and zoom all the maps But a good deal of the increase in size is due to a much stronger emphasis in UDMS 5 on user friendliness Earlier versions relied on a hardcopy User s Manual to explain the nature and operation of each part of the program As a result screen layout and screen prompts were minimal UDMS 5 by contrast is designed for use without a printed manual Each part of the program incorporates a complete SIn terms of execution time the slowest part of UDMS is the shortest path algorithm In earlier versions of UDMS this algorithm might be executed several times for the same network In UDMS 5 shortest paths are calculated once for each network as part of the process of creating the network The biggest incompatibility between BASICA and GW BASIC encountered during the writing of UDMS 5 involved the use of line 25 for user input In GW BASIC the line feed caused by pressing ENTER after responding to an INPUT statement in line 25 can be suppressed by immediately LOCATEing to another line even if that line is line 25 again In BASICA
37. nt UDMS was even running on a VAX 11 780 UDMS and the green manual received their baptism of fire at a UNCHS sponsored Workshop in Bogot Colombia in April 1981 Shortly afterwards the entire package and manual were translated into Spanish by the Centro Habitat de Colombia at the Universidad Nacional de Colombia in Bogota Over The use of microcomputers as an example of high technology as appropriate technology HTAT has been promoted by the United Nations Centre for Human Settlements Habitat at least since 1980 Cartwright 1985 1987 Downloaded from www timcart com Urban Data Management Software 173 the next few years this version was used in a series of six more workshops aimed at improving the qualifications of human settlements planners in Colombia Meanwhile UNCHS Habitat organised Workshops in several other countries including one in Madras India in June 1981 and another in Buenos Aires Argentina in March 1982 During the period from 1981 to 1983 UDMS was supplied to several planning agencies in the Third World including the Urban Development Authority in Colombo Sri Lanka the Seychelles Housing Bank in Male Seychelles and in Serbo Croatian the Montenegro Republican Committee for Planning Building and Public Works in Titograd Yugoslavia Copies of UDMS were also distributed to numerous individuals in planning agencies and research institutions around the world In early 1983 a sli
38. nts areas and networks located on any two dimensional surface In its current version UDMS can calculate standard geographic data such as areas and centroids search for points within specified areas or regions e find the shortest distance between any points on a network perform statistical analyses of regional variables including linear regression and gravity modelling search for the optimum location of facilities in a plane or on a network and produce eight different kinds of maps all subject to enlargement or reduction of scale according to user requirements UDMS was developed by the United Nations Centre for Human Settlements Habitat in 1980 as a means of showing how microcomputers could serve as an appropriate technology for the planning and management of human settlements The authors are indebted to their colleague Dr Ignacio Armillas for advice on certain historical points However the views expressed here are the authors and do not necessarily reflect those of the United Nations or any of its agencies Address for correspondence Faculty of Environmental Studies York University 4700 Keele Street Downsview Ontario Canada M3J 2R2 The concept of socio technical analysis originated with Eric Trist in his studies of the impact of technology on coal mining Trist and Bamforth 1951 The idea has been applied widely Cartwright 1978 in situations ranging from textile production in India
39. nual Preliminary Draft Version 0 98 Nairobi UNCHS December 1980 Translated into Spanish as Manual del Usario conjunto Software para el Manejo de Datos Urbanos United Nations Centre for Human Settlements Habitat User s Manual Second edition Version 1 03 UNCHS Nairobi January 1983 United Nations Educational Scientific and Cultural Organization UNESCO Conceptual Framework and Guidelines for Establishing Geographic Information Systems Preliminary version Erik de Man W H Editor UNESCO Paris August 1984 Wiggins L L Three Low Cost Mapping Packages for Microcomputers APA Journal pp 480 488 Autumn 1986 Downloaded from www timcart com Urban Data Management Software 193 NOTE ON DISTRIBUTION OF UDMS The current version of UDMS is distributed without charge It runs under PC MS DOS on IBM or compatible microcomputers IBM graphics capability CGA or equivalent is required for the mapping routines but the rest of the package can be run without graphics If you have a colour monitor UDMS will run in colour if not UDMS will run in monochrome Printouts are optional and are done from the screen so the package can be run with or without a printer attached If you want printouts you will need a dot matrix printer capable of doing a graphics screen dump Write to UNCHS Habitat Box 30030 Nairobi Kenya for information on users in your country from whom you can arrange to get a copy of the UDMS package o
40. ny remember how and when to use such techiques years later The reason is clear enough without a computer the calculations involved in regressions are very tedious so planners naturally tend not to use regressions With a computer on the other hand regressions are very easy to do so their use in planning even on a day to day basis becomes correspondingly more feasible The result is that microcomputers have created a demand for training not just in computers but also in the kind of planning techniques whose use is made more practicable by access to a computer In other words the training needs created by microcomputers are not primarily computer training needs they are planning training needs In a sense what the microcomputer revolution reveals is not just that planners are not as computer literate as they should be but also that they may not know as much about some aspects of planning as they should either Perhaps this is why computers are sometimes perceived as a threat Perhaps too this is why a computer expert is not always the best person to provide the kind of training that planners really need Thus UDMS 5 is pre eminently a program for ordinary planners using ordinary microcomputers It does not require but will take advantage of colour and graphics digitiser and plotter routines are not provided but can easily be added UDMS 5 is written in a language BASIC and a programming style deliberately chosen to make the package ac
41. odes namely the weighting procedures Although these files WPn and WNn have only limited use in connection with optimum locations they are in principle variable files and could with a little modification to the program be used for gravity modelling Downloaded from www timcart com Urban Data Management Software 187 fact in a two optima case if you give UDMS two first approximations of which one is completely outside the set of points and the other is inside the algorithm will devote itself exclusively to optimising the location of the better guess Thus in multiple optima problems it is desirable for users to do several runs of the program using different first approximations until satisfied that they are at least close to the overall optimum locations In both cases UDMS 5 finds the optimum location by using an iterative process That is the program keeps looking for a better solution until the resulting reduction in the aggregate distance from the location s to all the points reaches a certain minimum This minimum relative change in distance called the convergence is set to a default value of one one thousandth of a percent 0 00001 but this can be redefined by the user Naturally a smaller convergence results in a more accurate solution however more iterations are required and so computation inevitably takes longer A somewhat similar approach is used in finding the optimum location in
42. oft BASIC which includes IBM BASICA GW BASIC and several other versions Only minor modifications were necessary to compile this code in Version 5 3 Moving to interpreted BASIC in the sixteen bit DOS environment meant an immediate increase of about 50 in available memory Microsoft BASIC in all its various guises is limited to working in only one segment or page of memory i e 64 Kb even though the microcomputer may in fact have up to ten or even more times as much RAM However since most of the operating system and the interpreter can now be located outside the BASIC work area this means that the memory available to programs is now around 60 Kb instead of 40 Kb Moreover Microsoft BASIC includes a built in function FRE that allows a program routinely to optimise the way in which the work area is being used this is commonly referred to as garbage collection This in turn allows for larger programs and or more efficient execution Thus interpreted versions of UDMS 5 will still run on a minimum system say 128 Kb RAM and two floppy disks although naturally more RAM and a hard disk can improve disk access time But UDMS 5 takes advantage of the greater flexibility of the new environment in two other important ways First of all the structure of UDMS 5 is much simpler than that of UDMS 1 In Version 5 2 there are only 6 programs instead of 30 and their average size is around 20 Kb instead of less than 2 Kb see Table 2 I
43. ompletely on the principle of WYSIWYG or What You See Is What You Get Earlier versions of UDMS relied on two other approaches occasionally the program offered a choice between printing to screen or printer but in most cases users were just advised that pressing Control P would result in the forthcoming screen display being echoed to the printer In UDMS 5 however all results whether text maps or other kinds of graphics are displayed first on the screen and then optionally on the printer providing it is capable of printing standard IBM screen graphics using the 1 As far as resolution is concerned most dot matrix printers nowadays actually give better than medium resolution or Mode 4 as IBM calls it This has led to at least one ingenious proposal in Pascal to match graphics displays on the screen with shadow displays located somewhere outside the active video page and plotted to a standard of resolution too high for display on the screen but appropriate for the pin density of the printer in use Under this scheme a screen dump would appear to be coming from the screen but would in fact be generated by the higher resolution shadow screen For further information see Chandler and Faulkner 1986 Downloaded from www timcart com Urban Data Management Software 179 SOK SSEKKXKKKX SE SSEXKKEXKKAKK SSS SE FSX KKK KAKAK KAKA KAAK AKA KKK K SESSSE SSK KA EAA AKKAKKKAAKKAKAKAKEKE OSS S9E5 FS SKK KAK
44. ore and more planners to make use of them Thus the last part of this paper looks in more detail at just how a package like UDMS can be expected to affect planning and the way planners do their work UDMS AND PLANNING The thesis of this paper has been that the growth and development of UDMS over the last 8 years reflects both the technological development of micro computers and the sociological response of the planning profession to the opportunities that presents Of course computers have been used in planning for decades But what microcomputers have done and done in a dramatic way is to increase the scope of those uses and the number of planners who have access to them The result is that developments in microcomputer hardware and software have both fuelled and been fuelled by developments in planning itself This same symbiosis can be seen in other professions besides planning of course and in some of these business and finance for example the rate of development has been even more remarkable But the impact of microcom puters on planning is none the less important for that and already some of its impacts are clearly visible One of the most obvious features of UDMS is that it produces maps Maps have traditionally played a very important role in planning especially physical planning However a map is only one way of displaying data albeit a particularly useful way of displaying data that have a spatial basis Nevertheless
45. r send a 3 5 or 5 25 inch disk and ask for a copy of the package to be mailed to you directly Downloaded from www timcart com
46. re UDMS Package Computers Environment and Urban Systems pp 165 173 10 3 4 1986 Robinson V B and Coiner J C Microcomputer Geoprocessing as a Minimum Technology Solution for Data Management in Developing Countries Proceedings of the Urban and Regional Information Systems Association pp 214 226 1981 Rosenblum J and Jacobs D Performance Programming Developing a Single Program for a Variety of IBM PC Compatibles BYTE Third Annual Special Issue pp 181 194 1986 Rushton G Optimal Location of Facilities COMPress Wentworth 1979 Sawicki D S Microcomputer Applications in Planning APA Journal 51 2 209 215 Spring 1985 Schneider D I PEEKing at Your PC s Memory Parts 1 and 2 PCMagazine 12 and 26 November pp 201 218 and 187 208 1985 Trist E and Bamforth K W Some Social and Psychological Consequences of the Long Wall Method of Coal Getting Human Relations 4 1951 United Nations Centre for Human Settlements Habitat A Microcomputer Physical Planning System for Habitat Technical Notes No 5 Nairobi UNCHS 1982 United Nations Centre for Human Settlements Habitat Urban Data Management Software UDMS Instructor s Manual UNCHS Nairobi June 1983 United Nations Centre for Human Settlements Habitat Programme Listing Version 1 01 March April 1983 Nairobi UNCHS June 1983 United Nations Centre for Human Settlements Habitat User s Ma
47. roids the PTC file but not with any other points Thus the gravity model is effectively limited to analysing interactions between regions and these inter actions are assumed to be concentrated at their respective centroids It is to be hoped that here too UDMS can be made more flexible and more sophisticated in its next version Optimum location UDMS 1 provided for finding optimum locations either in a plane or on a network and both of these options are preserved in UDMS 5 However the algorithms used and their presentation to the user have been significantly improved in UDMS S UDMS 5 finds the optimum location or locations on a plane relative to the aggregate distance from a set of points stored in a points datafile PTn If desired the points can be weighted using values which have been stored in a points weights datafile WPn The algorithm requires the user to provide a first approximation to the solution even if it is only a guess Then what the program in fact does is to examine all possible improvements on that guess and choose the best one In the case of single optimum problems this amounts to finding the optimum location But in the case of multiple optima there is no guarantee that the best possible improvement on a first approximation is in fact an overall optimum In 20 Compare Ottensman 1985 chapters 7 and 8 7iIn fact there is already a mechanism in UDMS 5 for relating variables to points and n
48. rom www timcart com 188 T J Cartwright et al eight possible maps can be produced based on any combination of variable point and network overlays These maps can be drawn with or without regional boundaries with or without grid reference lines and with or without identification numbers for regions and in Version 5 3 points Second all maps make use of colour and where appropriate colour tiling Variable overlays can display up to nine different classes or categories of data Points and networks also make use of different colours and or different symbols dots squares crosses efc Third all maps can be moved about on the screen and magnified or reduced to scale With two key strokes any map can be panned up down left or right by varying amounts Similarly any map can be zoomed closer or farther away by varying amounts Together these two capabilities allow the user to focus in on any desired part of a map There is also a restore command that produces an instant re drawing of the original map Map legends appear on subsequent screens and users can cycle back to the map after seeing the legends with the option of adding or deleting region numbers and grid reference lines The pan and zoom features are possible because of the addition of two important commands to BASIC in the 16 bit DOS environment namely VIEW and WINDOW These commands depend in turn on services 6 and 7 of Interrupt 16 in th
49. s network distances shortest paths node weights etc calculates geographical character istics for regions and descriptive statistics of variables UDMS2 Identifies points in a file that lie either within a 16 523 14 283 circle of specified radius about a given point or within a specified region UDMS3 Performs multiple regression and gravity model 29 184 24 834 analyses of regional variables UDMS4 Finds single or multiple optimum location s 26 091 22 545 either in a plane or on a network UDMSS Produces eight different kinds of maps includ 25 088 21 360 ing any combination of variable points and network overlays with or without grid lines and regional identification numbers Total UDMS program files 153 846 131 736 Average per program 25 641 21 956 Note In addition to the six programs shown above the complete UDMS S package includes a number of text files and some sample data files The text files consist of a disk manual called UDMS MAN 19 840 bytes a licence agreement UDMSFORM DOC a short read me file and in Version 5 2 but not Version 5 3 a file containing notes on converting UDMS 1 data files for use with UDMS 5 UDMSFILE DOC and a sample AUTOEXEC BAT file hard copy depends of course on the capabilities of the printer but the superior capabilities of UDMS 5 can be seen from a comparison of Figs 1 and 2 below Still another advantage of the sixteen bit DOS environment is that printouts in UDMS S5 can be based c
50. se are 1 spatial search 2 linear regression and gravity model 3 optimum location and shortest path and 4 mapping In each case UDMS 5 provides improvements in algorithms and displays compared to those available in earlier versions Spatial search Ironically the apparently simple task of determining if a given point is located within a given area turns out to be a very difficult problem In some cases of course the answer is obvious but it is difficult to find an algorithm that works with polygons of any conceivable shape and orientation relative to the given point Searching for a point in a rectangle is a trivial problem It is necessary only to determine whether each of the co ordinates of the point lies between the respective maximum and minimum values for the rectangle i e its lower left and upper right corners A point either of whose co ordinates exactly equalled the corresponding maximum or minimum value would of course lie on the boundary of the rectangle 17See Dykstra 1986 and Wiggins 1986 See AIT HSDD 1986 Downloaded from www timcart com Urban Data Management Software 185 It is also easy enough to determine whether a point lies within a circle of given radius about a given centre If the distance of the point from the centre of the circle easily determined by the Pythagorean theorem is less than the radius then the point lies within the circle Again a point whose distance from the centre
51. tances and weights Table 3 provides a detailed description of the file structure of UDMS S in comparison with earlier versions 13Tn fact there is one other datafile necessitated by the peculiarities of the BASIC PAINT command which is used to shade map regions to show regional variables Essentially the PAINT command starts from a given point and colours the adjacent points until it meets the region boundaries Thus to PAINT a region you must have a point located within that region a point on the boundary or outside the region will not do For convex regions the centroid can serve as the starting point however in say a crescent shaped region the centroid may lie outside the region UDMS 5 therefore requires a special points file called PNT consisting of one point for each region that is known to be physically inside that region Downloaded from www timcart com 182 T J Cartwright et al Table 3 The datafile structure of UDMS 5 Filename Description of datafile structure DAT Initial raw map datafile created outside UDMS using any appropriate data entry program or device consists of two data elements for each point on the boundary of the map its X co ordinate and its Y co ordinate This file has no counterpart in earlier versions of UDMS COO Map co ordinates file consists of DAT with point identification numbers and file header and footer added by UDMS REG Re
52. ter and test their datafiles before they ever got to use UDMS itself Even with more flexible and user friendly interfaces than ED such as Wordstar or Supercalc errors were still frequent Moreover errors in creating datafiles really have little to do with UDMS so they have little didactic value Worse still the effect of such problems is particularly debilitating when one of the purposes is to demonstrate how microcomputers can make planning easier and more fun The solution adopted in UDMS 5 is something of a hybrid It was arrived at partly as a natural evolution from the earlier approach and partly to facilitate 6See Section 4 and Appendix I respectively in the User s Manual 1983 Downloaded from www timcart com 184 T J Cartwright et al automated data entry e g by digitiser and incorporation into UDMS of pre recorded maps from other sources In UDMS 5 the basic map file DAT is still created outside the program environment as it was in UDMS 1 using any word processing program or spreadsheet capable of producing a plain ASCII file But in UDMS S all other datafiles can be created within the UDMS environment Most of these datafiles can also be created and edited outside UDMS if that is desired since all are plain ASCII files The only file which must be created within UDMS is the network file NWn because UDMS simultaneously creates several other files required for analysing the network To make the DAT
53. tion Eight years ago while some people were convinced that microcomputers would be important in planning few people had a clear idea of exactly what that would mean Now there are established areas of microcomputer use in planning and experienced if still non specialist users to respond to UDMS like other software is now looking for a niche in an increasingly competitive market place in both industrialised and developing countries Microcomputers are challenging the way planners use data the way planning education is provided and the way planning resources are distributed In each of these respects UDMS 5 provides a small but instructive illustration of how the planning profession has responded to the microcomputer revolution BIBLIOGRAPHY American Farmland Trust Survey of Geographic Information Systems for Natural Resources Decision Making at the Local Level Washington mimeo August 1985 Asian Institute of Technology Human Settlements Development Division AIT HSDD Report on the Joint Workshop on Microcomputer Applications to Human Settlements Planning and Management Held at AIT Bangkok Thailand 18 29 August 1986 Kammeier H D er al Editors Bangkok mimeo September 1986 Baxter R S Computer and Statistical Techniques for Planners Methuen London 1976 Cartwright T J Information Systems for Planning in Developing Countries Some Lessons from the Experience of the United Nations Centre for Human Set
54. tlements Habitat Intl 11 1 1987 Cartwright T J Microcomputers as Appropriate Technology for Human Settlements Planning Habitat News 1985 Cartwright T J Planning the Education of Planners Contact 11 2 45 50 1979 Cartwright T J Systems Theory and Social Organization a Special Case of the General Theory in Progress in Cybernetics and Systems Research Trappl R and Pask G Editors pp 153 160 Hemisphere Washington 1978 27See Robinson and Coiner 1981 pp 1 2 reprinted as Annex HI in UNCHS Instructor s Manual 1983 HAB 12 4 M Downloaded from www timcart com 192 T J Cartwright et al Chandler R and Faulkner G A Virtual Graphics Screen PC Tech Journal pp 134 185 September 1986 Dykstra D Mapping Strategies PC World pp 260 271 October 1986 International Business Machines IBM BASIC Version 3 10 Personal Computer Hardware Reference Library No date International Business Machines IBM The Guide to Software for Developing Countries First edition by Coiner J C et al IBM Paris September 1985 Kammeier H D Microcomputer Based Assessment of the Accessibility of Central Place Services The Asian Geographer September 1986 Krueckeberg D A and Silvers A L Urban Planning Analysis Methods and Models John Wiley New York 1974 Landis J D Electronic Spreadsheets in Planning the Case of Shiftshare Analysis APA Journal
55. twork nodes file consists of identification of the beginning node end node and direction of each link between the associated network nodes This file was called LNK in earlier versions of UDMS Dnm Network distance file where nm are the last two characters of an associated link definition file consists of the beginning node end node and distance between them for each link in the associated link file This file was called DST in earlier versions of UDMS Xnm Network distance matrix file where nm are the last two characters of associated link definition and network distance files consists of a matrix of the shortest path distances between each and every node in the associated network This file was called DMX in earlier versions of UDMS WNn Nodes weights file where n is the last character of an associated network node definition file consists of a set of weights corresponding to each of the nodes in the associated network file This file had no counterpart in earlier versions of UDMS Note The file structure of earlier versions of UDMS was complicated by two factors First the use of filename extensions was in most cases too rigid to permit more than one file of each type consequently the filename itself had to be varied even for files pertaining to the same basic map In UDMS 5 all filenames pertaining to the same map can have the same filename only the extension is varied Second earlier versions of
56. using UDMSIS UDMS S displays its results in monochrome and low resolution except for maps which are not displayed at all on systems which do not have a colour graphics adapter Similarly whenever printouts are requested UDMS S5 checks to make sure that the printer is on and ready only if not is the user prompted to put things right In a somewhat more light hearted vein UDMS 5 even checks the system clock to determine whether it should greet users with Good Morning Good Afternoon or Good Evening All these refinements are based on the ability to examine by means of the PEEK function the appropriate locations in memory Another important innovation in UDMS S which was facilitated by the extra capacity of the sixteen bit DOS environment is that the structure of the entire program was standardised In earlier versions of UDMS the structure of each module followed its own logic In UDMS 5 on the other hand each module has five sections identifiable by the system of line numbering Line numbers were retained in the compiled version even though they are not necessary partly to facilitate conversion e g the same GOTO references could be used and partly to help preserve the identity of the program s structure the five sections of each module are as follows See Schneider 1985 for a list of important memory addresses in the IBM PC Downloaded from www timcart com Urban Data Management Software 181 Lines
57. variables was set at four While this was done to facilitate screen writing and not for any technical reason it was nonetheless felt that most users would not encounter many situations where they would need to examine more than four independent variables In the gravity model part of the program the algorithm from UDMS 1 was adopted almost intact in UDMS S In this approach UDMS assumes a simple form of the gravity model in which interactions or flows between centres are a function of some characteristic of those centres and their distances from each other Using a special user defined interaction matrix file ICn as well as variable data from the variables file VAR UDMS transforms the gravity model into a linear equation in two unknowns Then using the regression model in the first part of the program UDMS can estimate the parameters of the regression line using either distance or the selected characteristic as the independent variable This is a somewhat unorthodox approach to gravit modelling and may well be a candidate for more thorough revision in UDMS 6 Another limitation in the gravity model that persists from UDMS 1 is the fact that it provides only for interactions between regions For one thing the only variable data that can be accommodated in UDMS are regional variables cannot be associated with points in a points file for example Similarly data on interactions or flows in the ICn file are associated with regional cent
58. xt mode double width This is suitable for labelling regions of which there might be a dozen or so but becomes unreadable when there are a hundred or more points on the screen Accordingly points are labelled by means of a special routine adapted from Parsly 1986 that reads the dot pattern for each character from the table in ROM starting at location FO00 FA6E and prints a half size version However even for the regions with their full size labels there are still difficulties To start with there has to be a point in each region at which to locate the label Once again the regional centroids will not do because centroids are not necessarily inside a region so we had to use the special PAINT points discussed above see Footnote 15 Second you cannot PRINT a character on the screen at a location defined in terms of pixels or pels to use the IBM term which is how all map locations are defined when using VIEW and WINDOW To use the PRINT command the only thing you can do to get the cursor where you want it is to use the LOCATE command So what we had to do was get the location of the point at which to PRINT the region number scale it according to the current VIEW and WINDOW settings convert it to row and column poisitions LOCATE the cursor there and then PRINT the region number Proving once again that it is just as well that computers are so fast they can manage to so complicate even the simplest of tasks that were it not for the

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