Troubleshooting GPS Data
Contents
1. Mi Mmaplib brocku ca Introduction GPS data can appear in a variety of formats txt csv gpx xls xIsx tab etc and coordinate units resulting in messy data that must be cleaned up before it can be used in ArcGIS This document attempts to address some common issues encountered with GPS data Breck MAP DATA amp GIS LIBRARY Troubleshooting GPS Data If the data hasn t been loaded from the GPS follow the steps for getting waypoints from the GPS to GIS using DNRGPS utility This is the optimal method for plotting GPS data If the data is already in gox format run the conversion tool GPX to Features in ArcGIS GPS Data in Degrees Minutes Seconds Ideally latitude longitude coordinate pairs are most useful in decimal degree format hddd dddd However some cases have data in degrees and decimal minutes or even degrees minutes and decimal seconds The data file txt or csv will be fixed using Microsoft Excel 1 Run Excel Select File gt Open Navigate to the location of the text file if necessary change the file type to Text Files in order to see all files of this type Text Import Wizard e Step 1 o Identify the data as delimited tab or comma or fixed width Identify the start import at row click Next e Step 2 o Choose delimiter preview indicates how your choice affects the data o Click Next Text Import Wizard Step 2 of 3 aa This screen lets you set the del2. assuming a Niagara location CONCATENATE 6 B2 00 HIT ENTER RESULTS IN 661500 7 Click in the cell where you entered the equation and drag the black handle down to apply the function to the rest of the list 8 Enter anew title for Northing Click the first cell and enter the following equation to expand the grid reference CONCATENATE 47 C2 00 RESULTS IN 4748800 The table should look like this A E C D E site utm Easting Northing 1 615 438 661500 4745800 2 318 4751800 3 356 4436556000 4744300 4 303 487 650300 4745700 5 365 65860 4750500 Jeo 4747000 9 9 Save the Excel file and save a second copy in CSV format 10 Close Excel before continuing with steps to plot X Y data in ArcGIS Plotting X Y Data in ArcGIS Page 7 It is simple to plot X Y locations if the data table ideally in CSV format has two separate fields for coordinate pairs such as latitude and longitude decimal degrees or UTM eastings and northings The table may look similar to this 2 6 10 11 12 13 14 A B C D 1 Name Description Latitude Longitude 2 GC10119 OH CANADA EH 43 19319444 9 26611111 3 GC1O20C WEEPING WILLOW CACHE 43 19463889 79 26763889 4 GC1IEPM BROCK BASEMENT CACHE 43 12097222 7925219444 9 GC1IEQ A TRIBUTE TO SCRATCH N WIN 43 11463889 9 25 61111 6 GC1LINOK GRANDPA S CACHE 43 18130556 9 27186111 7 GC1Ix9Y THE 3 AMIGO S CACHE 43 18986111 79 25258333 A B C D 1 Name Description
3. 0 09 Conditional Formatas Cell Insert Delete b Sort amp Find amp Formatting Tabley Styles v v Filter Select Clipboard amp Font F Alignment F Number F Styles Cells Cell Size Al v f Header SE Row Height AutoFit Row Height A B C D E F 6 H l J K L M N O R d C Column Width Descriptic Type 1 Header Name Position Altitude Depth Proximity Temperat Display M Color Symbol Facility City State 2 AutoFit Column Width 3 Waypoint 5 03 AUG 07 User Way 17 T 49991243m 0 0ft Symbol amp Unknown Crossing Default Width 4 Waypoint 6 03 AUG 07 User Way 17 T 49991 243 m 0 0 ft Symbol amp Unknown Crossing Visibility 5 Waypoint 7 10 AUG 07 User Wayj17N6917 112m 0 0ft Symbol amp Unknown Crossing Hide amp Unhide gt 6 Waypoint 8 10 AUG 07 User Way 17 T 64031107 m 0 0 ft Symbol amp Unknown Crossing igen ars z 7 Waypoint 9 24 AUG 07 User Way 17 T 640760 4783885 0 0 ft Symbol amp Unknown Crossing Danana Chant In the above example UTM coordinates are found in column E under the name Position This format shows eastings and northings in a single column GIS requires they be in separate columns Page 5 Splitting the Column Before splitting the column it is a good idea to clean up the table by deleted redundant columns and rows Make sure the Position column has 3 blank columns to the right where parsed data will be saved Activate the DATA ribbon Select the column containing the UTM
4. 9 4 GC11EPM BROCK BASEMENT CACHE 43 12097222 79 25219444 5 GC11EQ 2 A TRIBUTE TO SCRATCH N WIN 43 11463889 79 25761111 6 GC11NOK GRANDPA S CACHE 43 18130556 79 27186111 7 GC11x9 THE 3 AMIGO S CACHE 43 16966111 F9 25258333 68 GC12PQ00 OH GEOCACHE WHERE MIGHT YOU B 43 12216667 79 2004 7222 9 GC1310 CALM 43 21283333 9 2494 F222 4 Save the Excel file 5 Save a second copy in CSV format to be used in ArcGIS If prompted with a warning click continue 6 Close all Excel windows before proceeding If this section was useful move on to the instructions for Plotting X Y Data in ArcGIS found on page 7 Page 4 GPS Data in UTM Sometimes GPS data has coordinates described by UTM eastings and northings in a single column Before these coordinates can be plotted they must be parsed into separate fields Sample text file with UTM coordinates this is a very messy file Grid UTM Datum NAD83 Header Name Description Type Position Altitude Depth Proximity Temperature Display Mode Color Symbol Facility Categories Waypoint 005 03 AUG 07 1 02 13PM User Waypoint 17 T 499914 4935922 243 m 0 0 ft Symbol amp Name Unknown Crossing Waypoint 006 03 AUG 07 1 03 16PM User Waypoint 17 T 499915 4935922 243 m 0 0 ft Symbol amp Name Unknown Crossing Waypoint 007 10 AUG 07 6 38 25PM User Waypoint 17 N 691735 18635 112 m 0 0 ft Symbol amp Name Unknown Crossing Waypoint 808 10 AUG 07 6 54 21PM User Waypoint 17 T 640318 4780537 107
5. CH N WIN 641757 4775020 6 GC1INOK GRANDPA S CACHE 4782398 7 GC11x9Y THE 3 AMIGO S CACHE 641991 4783380 Page 6 Field data represented by 6 digit UTM references A B Data gathered in the field using a 6 digit UTM grid reference system must be expanded to reflect 1 site utm more complete UTM coordinate pairs In a 6 digit grid reference the first 3 digits represent the z k easting and the last 3 the northing The 6 digit reference must be split in two then expanded 1 z naa Splitting the Column a ee 6 5 588565 1 Activate the DATA ribbon 7 6 586470 2 Select the column containing the 6 digit reference 3 From Data Tools select Text to Columns The 3 step wizard will guide us to split this column Step 1 Select Fixed Width Click Next Step 2 Identify breaklines within the column by clicking between the 3 and 4 character Click Next Step 3 Default data format is acceptable Click Finish A C 4 The coordinate pairs have been parsed into 2 separate columns zite ini 5 Save the document in Excel xlsx format 1 615 488 2 568 518 Before continuing you must confirm the geographic area where the points were gathered 3 555 443 Refer to a 1 50k topographic map of the area to identify the expanded values of 4 503 487 northings eastings as well as the UTM Grid Zone Niagara is in 17N 3 388 305 6 586 470 6 Enter a new column title for Easting Click in the first cell and enter the following equation to expand the grid reference
6. Easting Northing 2 GC10119 OH CANADA EH 4783727 3 amp C102QC WEEPING WILLOW CACHE 640757 4783866 4 GC1IEPM BROCK BASEMENT CACHE 642183 4775732 3 GC11EQ2 A TRIBUTE TO SCRATCH N WIN 641757 4775020 6 GC1LINOK GRANDPA S CACHE 640445 4782398 F GC1IX9Y THE 3 AMIGO S CACHE 641991 4783380 Run ArcMap Click Add Data and navigate to the CSV file select it and click Add The table appears in the Table of Contents NOTE that the file must be closed in all other applications or you will receive error messages Right click the table and select Display XY Data In the Add XY Data dialog specify the fields that contain the X and Y coordinates with X corresponding to longitude easting values and Y corresponding to latitude northing values TIP the following table summarizes X Y formats Latitude UTM Y UTM X 43 degrees 4 763 000 metres N Longitude 79 degrees 623 000 metres E Under Coordinate System of Input Coordinates click Edit Identify the spatial reference according to your data For Latitude Longitude use Geographic Coordinate Systems gt North America gt NAD 1983 For UTM Eastings Northings in most of Southern Ontario use Projected Coordinate Systems gt UTM gt NAD 1983 gt NAD 1983 UTM Zone 17N Click OK The Display XY Data dialogue box is now complete Click OK A message box will appear stating that the table does not have an Object ID field This field will automatically be created in the next st
7. M N O Q fm i ee _ _ ES uu olumn Width 1 Header Name DescripType Positiot Altitud Depth Proximi Tempe Display Color Symbol Facility City State Country Date Mod Link a 2 AutoFit Column Width 3 Waypoi 5 03 AUG User Wi N44 34 243m 0 0ft Symbol Unknov Crossin Default Width 4 Waypoi 6 03 AUG User Wi N44 34 243m 0 0ft Symbol Unknov Crossin Visibility 5 Waypoi 7 10 AUG User Wi NO 10 01112m 0 0ft Symbol Unknov Crossin Hide amp Unhide b 6 Waypoi 8 10 AUG User Wi N43 09 107m 0 0ft Symbol Unknov Crossin Organize Sheets 7 Waypoi 9 24 AUG User Wi N43 11 40 7 W750 0 ft Symbol Unknov Crossin m ans 8 Waypoi 10 24 AUG User Wi N43 11 35 8 W7 0 0 ft Symbol Unknov Crossin e In the above example Lat Long coordinates are found in column E under the name Position This format shows both latitude and longitude in a single column as degrees minutes and decimal seconds Unfortunately this format is unacceptable for GIS We will convert them to decimal degrees Converting to Decimal Degrees Remove unwanted columns GPS data sometimes includes a lot of extra data not pertinent to your specific study 1 Identify columns and or rows to delete and tidy up the table 2 When all changes are made copy paste the POSITION column so that it is the last populated column if necessary Splitting the Column 1 Activate the DATA ribbon Select the column containing the coordinate pairs 3 From Data Tools selec
8. coordinates From Data Tools select Text to Columns The 3 step wizard will guide us to split this column oe sy Se Step 1 select Fixed Width Click Next Step 2 Identify breaklines within the column Each piece of the coordinates will need to have separate columns Click Next Step 3 default data format is acceptable Click Finish 6 The coordinate pairs have been parsed into 4 separate columns In the example below columns G and H include eastings and northings respectively Change the name of these columns accordingly A B C D E F G H 1 Header Name Description Type Po si tion 2 Waypoint GC10119 OH CANADA EH User Waypoint 17T Al 4783727 3 Waypoint GC1020C WEEPING WILLOW CACHE User Waypoint 17T 4783886 4 Waypoint GC11EPM BROCK BASEMENT CACHE User Waypoint 17T 642183 4775732 5 Waypoint GC11EQ2 A TRIBUTE TO SCRATCH N WIN User Waypoint 17T 641757 4775020 6 Waypoint GC1INOK GRANDPA S CACHE User Waypoint 17T 640445 4782398 7 Waypoint GC11X9Y THE 3 AMIGO S CACHE User Waypoint 17T 641991 4783380 7 Clean up the table by deleting unwanted columns and rows 8 Save your work in a new Excel workbook xlsx Then save as a CSV file say YES to prompt and close Excel 9 Follow the steps for Plotting X Y Data in ArcGIS A B C D 1 Name Description Easting Northing 2 GC10119 OH CANADA EH 4783727 3 GC1020C WEEPING WILLOW CACHE 640757 4783886 4 GC11EPM BROCK BASEMENT CACHE 612183 4775732 5 GC11EQ2 A TRIBUTE TO SCRAT
9. dundant columns 1 Atthis point the latitude and longitude columns are reliant on the 8 columns we created earlier If we tried to delete the seemingly meaningless columns we would lose the calculated values 2 To make the calculated values permanent select the 2 columns hit Ctrl C on the keyboard or right click and select Copy 3 Highlight two empty columns right click and from the paste options choose the second option called paste values ysi tio n Latitude Longitude Latitude Longitude 43 11 35 5 W 79 15 58 43 1931944 79 26611111 43 19319444 79 266111711 43 11 40 7 W 79 16 3 5 43 19463889 79 26763889 43 19463889 79 2676035889 43 T 15 5 W 79 15 7 9 43 12097222 79 2521944 43 12097222 79 2521944 43 6 52 7 W 79 15 2 4 43 11 463889 79 25 761111 43 11463889 79 25701111 43 10 52 7 W 79 16 18 7 43 18130556 79 2 7186111 43 18130556 79 27186111 43 11 23 5 W 79 15 9 3 43 18986111 79 25258333 43 18986111 F79 25258333 43 Fi 19 8 W 79 15 37 7 43 1221666 79 20047222 43 12216667 79 20047222 43 12 46 2 W 79 14 32 9 43 2126533 33 79 2424 7222 43 21283333 79 2424 7222 43 10 ow 79 11 47 6 43 16916667 79 19661111 43 16916667 79 19661111 IT is now safe to highlight and delete the 8 parsed columns plus the first 2 calculated lat long columns resulting in a tidy Excel table A B C D 1 Name Description Latitude Longitude 2 GC10119 OH CANADA EH 43 19319444 79 20611111 3 GC102QC WEEPING WILLOW CACHE 43 19463889 79 2676388
10. eps Click OK The XY data is displayed as points on the map This point data file is called an event file To make a permanent shape file right click on the point data layer and choose Data gt Export Data Ensure the Save as type is shapefile and the location is your student space Click Save Accept the rest of the defaults and click OK When prompted to add the exported data to the map as a layer click Yes The layer is now a permanent shape file including an Object ID field meaning the data may be used in analysis
11. imiters your data contains You can see how your text is affected in the preview below Delimiters Tab Fe Semicolon Comma Space Other Data preview aypoint po e Step 3 L Treat consecutive delimiters as one Text qualifier v escription 3 AUG 07 1 02 13PM ser Waypoint N44 34 35 9 W81 00 03 9 243 3 AUG 07 1 03 16PM ser Waypoint N44 34 35 9 W81 00 03 9 43 v Cancel lt Back Finish o Set the data format for each column this can also be done later if necessary o Click Finish Page 2 The table appears squished 3 To expand columns click and drag across all column headers A through L to select the affected data 4 From the HOME ribbon and CELLS gt Format section choose AutoFit Column Width H x GPSpts_decimal_seconds txt Excel amp I FILE HOME INSERT PAGE LAYOUT FORMULAS DATA REVIEW VIEW Esri Maps Sharon Janzen m X oJ 5y m a a a gt a D n A Oa nn W r a a Ra n ih a Calibri 11 A A X Wrap Text General Beg ee H E zY A Paste B IU Arv P a3 Merge amp Center 3 e0 00 Conditional Formatas Cell Insert Delete Sort amp Find amp F 7 E 2 A Esl Merg 7 ai Formatting Table Styles hg v 7 Filter Select Clipboard Font F Alignment F Number F Styles Cells Cell Size ae Al lt fi Header HE Row Height AutoFit Row Height A B C D E F G H l J K L
12. m 0 0 ft Symbol amp Name Unknown Crossing Waypoint 009 24 AUG 07 5 43 36PM User Waypoint 17 T 640760 4783885 0 0 ft Symbol amp Name Unknown Crossing Waypoint 010 24 AUG 07 5 45 23PM User Waypoint 17 T 640655 4783732 0 0 ft Symbol amp Name Unknown Crossing Waypoint 024 25 SEP 07 9 42 03AM User Waypoint 17 T 639431 4782830 70 3 m 0 0 ft Symbol amp Name Unknown Crossing Waypoint 025 24 OCT 87 3 52 51PM User Waypoint 17 T 670520 4752678 162 m 0 0 ft Symbol amp Name Unknown Crossing 1 Run Excel Select File gt Open Navigate to the location of the text file if necessary change the file type to Text Files in order to see all files of this type Text Import Wizard e Step 1 Identify the data as delimited tab or comma or fixed width o Identify the start import at row o click Next e Step 2 o Choose delimiter preview indicates how your choice affects the data o Click Next e Step 3 o Set the data format for each column this can also be done later if necessary o Click Finish The table appears squished 3 To expand columns click and drag across all column headers A through L to select the affected data 4 Fromthe HOME ribbon and CELLS gt Format section choose AutoFit Column Width Da z l oO ik d Calibri 1 lt A A V EeWrapTet General F 4 ey em x 2 Ay Ht B Ed Tp H Z B x n ss 1 on iti 7 i Paste v B I U fy De A Z Z amp j Merge amp Center 3
13. t Text to Columns The 3 step wizard will guide us to split this column such that we will be able to calculate decimal degrees Step 1 select Fixed Width Click Next Data preview Step 2 Identify breaklines within the column Each piece of the coordinates will need to have separate columns Click Next Finish Step 3 default data format is acceptable Click Finish Cancel lt Back 4 The coordinate pairs have been parsed into 8 separate columns 5 Save your work in a new Excel workbook xlsx Calculating Latitude 1 Enter anew column with the name Latitude 2 Click the cell directly below and enter the following equation using corresponding cells Degrees Minutes 60 Seconds 3600 HIT ENTER D2 E2 60 F2 3600 RESULTS IN 43 19319 Page 3 3 Click the cell containing the equation and click drag the black handle in the lower right down the entire column to apply the equation to the whole column Calculating Longitude 1 Click the first row cell of the first vacant column and enter the name Latitude Click the cell directly below and enter the following equation using corresponding cells 1 Degrees Minutes 60 Seconds 3600 HIT ENTER 1 H2 12 60 J2 3600 RESULTS IN 79 2661111 3 Click the cell containing the equation and click drag the black handle in the lower right down to apply the equation to the whole column 4 Save the Excel file Deleting re
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