Finding Your Way with GpsDrive

Once you have GpsDrive and any optional software you want installed, and you know the GPS receiver is working, try GpsDrive. You will see a splash screen, then the main window. Then you will see one nag screen for the first and last time. The author, Fritz Ganter, pays for the server for the Web page out of his own pocket and would appreciate your contribution.

Once you close the nag box, you should see an image in the map section of the GpsDrive window. This is a placeholder until you get a map for yourself. The first thing to do is turn off simulation mode in the Preferences menu. While you are there, if you want statute or nautical miles, select that option.

To get your first map, determine the latitude and longitude of the center of your new map. Then put the program into position mode (lower-left area of the menu). Next, create a waypoint with the X key, and enter the lat and long of the map center. Use minus signs to indicate south and west (Figure 1).

Figure 1. The Main Window on the First Use of GpsDrive

Use the find tool (upper-left menu) to go to the waypoint. Now, click the Download Map entry on the left side of the main window. You will notice that your lat and long are the defaults. Select your scale and source, and grab a map. Bingo! The new map is displayed immediately. If this is a location you use a lot, you may want to download several maps at different scales.

GpsDrive has three modes: position, normal and simulation.

Use position mode to move around on your maps. Enter position mode by checking Pos. mode on the lower-left side of the main window. Once you are in position mode, as you jump around by clicking on the map, GpsDrive shows you the distance and bearing from the current position (marked with a blue square) to the target (indicated by an alternating red and blue cross).

For example, once you have a small-scale map of a large area, you can move around and download selected large-scale maps for interesting locations. You also can define waypoints using position mode.

In normal mode, GpsDrive has a fix from a GPS receiver and is tracking the position indicated by the receiver. As the position changes, GpsDrive pans across its supply of maps. GpsDrive comes up in normal mode.

In simulation mode, GpsDrive generates a path from a starting point to one or more waypoints. To enter simulation mode, bring up Preferences, go to the first settings tab and check Simulation. This is a fun mode, as you get to watch an imaginary vehicle move at high speeds across the countryside.

You will want several maps in different scales. I recommend you get a very small-scale map that covers all of your normal travel area. With this in place, you won't fall off your map if you accidentally click outside your area in position mode. The NASA maps (if you have the disk space) or the default map do this nicely.

In the GUI, you simply select the parameters for the map you want, and the server, and then get it. That's the easy way. However, the results may not tile well. You can get US Geological Survey maps from Topozone.com or street maps from Expedia.com.

If you know the latitude and longitude of the center point and the scale you want, enter these into the download map dialog and go. You also can enter position mode and click on existing maps until you get to the center of a new map you want and then download it.

Then, there is NASA topographical data. See the file README.nasamaps for details and Figure 2 for an example.

Figure 2. Southern New England shown by GpsDrive using NASA topographical data.

For a more systematic map collection, see the accompanying gpsfetchmap.pl.

Some of these map sources provide copyrighted data. Be sure you use the maps in a manner consistent with the permissions granted on the Web site.

You also can import your own maps. You need to know the latitude and longitude of the center point and the scale of the map. There is a druid to help you import maps under the Misc. menu in the top-left corner of the GpsDrive window.