Finding Your Way with GpsDrive
Now that you have some maps, it's time to play around with your new toy.
GpsDrive is well supplied with tool tips, so we only cover the highlights of the display here.
Right below the map in the main window, GpsDrive displays navigation data. Distance to the next waypoint and current speed are obvious. To the right of those is some information on waypoints, mobile targets visible on your friend's server, and the current time according to the GPS receiver.
To the left of the distance to waypoint display is GPS information. With no GPS, a rotating globe is shown. When a GPS is present, the globe is replaced by a signal strength meter for visible satellites. Its background is red if there is no fix; green if there is a fix.
To the left of the GPS data is a compass. The top of the compass indicates your current heading or the course you are sailing. The black pointer gives a bearing to the next waypoint.
A lot of settings are handled in the Preferences menu, which you can select from the left side of the main window. You already know about selecting your units of measure. If you are operating with an older computer, you may want to limit the amount of CPU time GpsDrive takes up, and turn off shadows, which require extra processing to draw.
In the second settings tab you will find some GPS-related settings. For example, you may elect to have GpsDrive access the receiver directly instead of through gpsd.
The SQL tab lets you select certain types of waypoints to include or exclude from the display. This lets you organize waypoints into categories and decide which ones to display. I use this with a set of waypoints for my preferred gas station chain. I can turn them on or off on the display, depending on whether I am looking for gasoline or not.
Once you have maps in hand, there are several controls you can use to manipulate them. For areas where you travel a lot, you probably have maps of several different scales. There are several ways to select between them. The first is to check Auto best map in the lower part of the left menu. This tells GpsDrive to select the best (largest scale) map available for the current location.
Below that, right above the area map, you can check on street or topographical maps, or both. With both checked, GpsDrive moves between the two types, which gives you the most coverage for the maps you have.
Turn Auto best map off and you have several ways of selecting scale. In the upper-left area of the main window, you will find two arrows. Click on the left arrow to move to a larger-scale map, on the right to move to a smaller-scale map. You also can move the slider on the very bottom-right side for the same effect. This sets the preferred scale, and GpsDrive stays as close to that scale as it can.
Within a given map, you also can zoom in and out. Use the two magnifying glass controls on the upper left of the main window. The current magnification is indicated in the upper-right corner of the main map. GpsDrive keeps the same level of zoom when it changes maps, which can be disconcerting.
First, make sure you have waypoints turned on and that you are using SQL or not, as appropriate.
There are several ways to set waypoints. You can hand-edit them into the text file or MySQL database, you can use the program gpsbabel to convert from other file formats or you even can download them from Wayhoo.com.
In position mode, you can enter a waypoint at the current position by pressing the X key, or you can enter a waypoint at the current mouse pointer with the Y key. You always can edit the parameters before you commit the waypoint.
Wardriving is the sport of driving around searching for Wi-Fi access points. For more, see the article “Discovering Wireless Networks” in the September 2003 issue of Linux Journal.
GpsDrive comes equipped with a friends server. This lets several people display each others' positions on their systems. You can run your own, or you can use any one you can find on the public Internet. This is real-time plotting of multiple vehicles' positions. This makes GpsDrive a great adjunct to a car rally or search-and-rescue mission.
If a user falls off the Net temporarily due to Wi-Fi signal loss, the user's last known position is displayed. Once he or she is back on the Net, displays are updated in seconds.
About the only thing missing from GpsDrive is street-level routing. To do this, the program needs an open source of street-level data. Commercial data usually runs in the area of 10,000 Euros, which is a showstopper. If you know of such a data source, please let the author know.
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