How to bring GPS data into ArcGIS, MS Excel, and databases

So you have collected your sample site locations with a Garmin GPS 60 and now you want to process them in ArcGIS or MS Excel?

Install a converter

To convert the data from the GPS unit to ArcGIS we recommend the “DNR Garmin” converter. Download it from http://www.dnr.state.mn.us/mis/gis/tools/arcview/extensions/DNRGarmin/DNRGarmin.html. Installation instructions are provided on the website.

Download and convert the GPS data

1. Connect the GPS device to your PC and switch it on.
2. Start DNR Garmin

Figure 1: DNR Garmin

1. Go to GPS > Set Port and make sure the correct port is selected. This has to be USB or Port 1 (COM), depending on where you connected the GPS unit.
2. If you want to download waypoints, go to Waypoint > Download, if you want to download Tracks, go to Track > Download.
3. Click the Data Table button, then select the Waypoint or Track option to list the data.

Figure 2: GPS Garmin data table

1. With your type of data selected (waypoints or tracks), go to File > Save To > File…, a Save As window opens
2. Navigate to the folder where you want to save the data, e.g. My Documents.
3. At the bottom of the window select the file type you want to save your data to:
   • For ArcGIS select ArcView Shapefile (Unprojected) (*.shp).
   • For MS Excel select Text File (comma delimited) (*.txt)
   • For databases select Text File (comma delimited) (*.txt) or whatever format your database software can read.
4. Enter a filename, e.g. MyGPSdata
5. Click Save.

View the data

Start the application you want to use the data with (ArcMap, MS Excel, MS Access, etc.) and load the file.

With ArcGIS: convert coordinates to British National Grid

Note that your coordinates are geographic (decimal degrees), referring to the WGS 84 datum.

If you want to overlay your data in ArcMap 9.2 with data that uses a different datum, like UK Ordnance Survey data, follow these steps:

1. In ArcMap or ArcCatalog open the toolbox and start the Project tool (Data Management Tools > Projections and Transformations > Project)
2. For Input Dataset select your Shapefile containing the GPS data, e.g. gpsdata.shp.
3. The Input Coordinate System may be set automatically to WGS1984, otherwise  select it (Geographic Coordinate Systems > World > WGS 1984).
4. Set a location and name for the Output Dataset, e.g. gpsdata_BNG.shp.
5. Set Output Coordinate System to British National Grid (Projected Coordinate Systems > National Grids > British National Grid).
6. Set Geographic Transformation to any of the available options. Do not leave blank.

The output file contains coordinates in British National Grid, referring to to the BNG’s underlying datum OSGB 1936.  It wil overlay correctly with UK Ordnance Survey data that uses the same datum.

Very technical note: the DNRGarmin software also allows you to download the data in a projected coordinate system, saving you the ArcGIS projection steps. However, the DNRGarmin software by default uses a geographic transformation for WGS84 > BNG that is different from the ones used by the OS.  Therefore data downloaded as ‘projected’ will not overlay correctly with OS data.