National Map Corps
This is a unique volunteer effort to help update the Nation's geospatial information. See the website for more details.
National Map Corps

You will find information regarding GPS functionality, types of GPS units, things you can do with a GPS unit, GPS tools, etc.
Units
Create/Upload/Download Waypoints, Tracks and Routes Using Google Maps
****Under construction***** ****New Update****
The following describes how to use the map below to generate data for upload to a GPS. Currently, only the CSV option works with the following directions.
06.21.06
Added an Export to GPX Format button that will create a GPX format for waypoints. The text that gets created can be copied into a textfile with (.GPX) extension, then run the GPSBabel command below for upload to the GPS unit.
More will be offered as time permits.
Please Checkback Later....
You can use the following instructions to create waypoints, tracks, and routes on this map and then use a freeware GPSBabel to convert this information into a generic format that can be read by a typical Garmin Unit. Similar steps are available for Magellan.
Create/Upload Steps
1. Create Points on the map (see below).
Take the CSV data and copy to NotePad and attach the csv extention (e.g. "sac1.csv"--use the quotes so an additional .txt extension is not added.
2. Download the gpsbabel zip and extract to directory
3. Run the command line where you installed the gpsbabel exe file to convert the CSV formatted file to the GPS Standard GPX format.
syntax: gpsbabel.exe -i csv -f sac1.csv -o gpx -F sac1.gpx
4. Run gpx to Garmin to upload data to a garmin unit. Substitute magellan for garmin if using Magellan. See GPSBabel documentation for more details.
syntax: gpsbabel.exe -i gpx -f sac1.gpx -o garmin -F com1:
The GPS points will be uploaded and tagged with WPT00X for waypoint names. IF you want custom names, then you can open the GPX file in a text editor and change the name, but you are limited to 8 or 10 characters depending on the kind of unit.
Download data from GPS unit to GPX format
1. Connect GPS unit to computer via serial/USB port. Turn GPS on. Note which port the unit is connected to COM1, COM2, etc
2. Run the command line where you installed the gpsbabel exe file to download the data from the GPS to a GPS Standard GPX format.
syntax: gpsbabel -i garmin -f com1: -o gpx -F gpsdata.gpx
for usb: gpsbabel -i garmin -f usb: -o gpx -F gpsdata.gpx
Check the GPSbabel site for more formats and information.
Next steps...import/read the GPX formatted file to show up in the Google map. There is also an option to create a KML file for Google Earth.
Download to KML (untested): gpsbabel -i garmin -f usb: -o kml -F myposition.kml
Google Maps JavaScript API Example
Create a line with clicks, then convert that to a list of points
This shows how to create a list of waypoints, track points, or route points with a Google Maps front end.
Debugging...
Google Map Stuff
***Under Construction***
This section provides information to get information from Google Maps to a GPS Unit. Since I am just becoming familiar with this, it may take some time to develop. These are both mentioned in the Google Maps Hacks. Check back.
- GMapToGPX - This is a link that explains how to get spatial information from Google Maps to a GPX file that can be loaded into many different kinds of GPS Units.
- GPS Babel - Another source for obtaining information from Google Maps to a GPS Unit.
- GPS Visualizer - This link allows anyone to upload a properly formatted GPS file that can then be viewed on a google map or to create a KML file for viewing with Google Earth.
GeoCaching
The Official Geocaching Site
You can set up a free account to start enjoying the fun world of finding stuff
Running, Cycling, High Endurance
Software
Garmin/Magellen (free/low cost)
VBGarmin (CDFG) - Free; provided by CA Fish and Game to upload/download GPS and import/export GIS shapefile data
Expert GPS - low cost GPS upload/download to many recreational use units. Provides access to TerraServer air photos and USGS topomaps. The GIS add-on bundle allows for import/export to GIS shapefile data.
- MacGPSPro - (low cost) GPS connector for use with Mac
Trimble
- GPS Correct - Provides the ability to correct GPS data that comes off of a high-end Trimble unit for use with ESRI software. Replaces the need for Pathfinder upload/download, and Differential Correction (post processing) steps. Will need ArcPad to use customized field forms and ArcPad Application Builder (VB Script) to create the customized field forms. Navigation is not available unless GPS Analyst is used or TerraSync data collection software is used. Will also process Trimble SSF files.
- GPS Analyst - Provides the same ability as above and allows for navigation in the field. GPS Analyst also has the ability to review and analyze data quality within ArcGIS. This extension is really used for the pure GIS organization or where GIS is predominant.
Field Comparison or Office Comparision between GPS Correct and GPS Analyst.
- Pathfinder - Provides the communcation link between GPS and computer. Import GIS/CAD data, create Data Dictionaries, upload/download data, differential correct (post process data), export to GIS/CAD/ascii, etc formats. Geographic, UTM, Albers, State plane, etc coordinate systems available.
