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LXGPS: A Review
I missed the first announcement of the LXGPS program and I regret that. I had been busy using two other GPS programs on both the Palmtop and on a laptop while traveling cross country.
When I downloaded LXGPS version 1.5 from www. palmtop.net and installed it on my Palmtop I was impressed. The program is very intuitive and handles the Tripmate GPS unit transparently and flawlessly. For instance, I could turn off the Palmtop, disconnect the serial cable, come back an hour later, reconnect the cable, turn the power on, press "Monitor" and the program would reinitialize the Tripmate and get a reading in under a minute. The other two programs failed to do this.
Furthermore, the LXGPS program has a variety of customization options that none of the other Palmtop GPS programs offer. For example, in addition to on-map displays of waypoints, a course line to pre-picked way points shows on screen. Even the map scroll is controllable. You can enter a number that represents a percent of the screen's area. When the position marker reaches this percentage of the screen, the map will shift and the position marker will be in the center of the screen again.
With the logging options, it would be possible to build a recording tracker for a gravel truck company for under $500 that would generate time and position proofs when windshield damage claims were presented. It would also be easy to import a wilderness map, put the Tripmate in a top pocket of a backpack and blow most of the handheld GPS units away on a hiking trek.
Finally, the cost! The author calls LXGPS copyrighted freeware but also indicates that it's "e-mail ware." You'll want to send him e-mail about your impressions and findings as part of the payment.
If you've got a Palmtop and access to a NMEA 0183 serial port GPS such as the Delorme Tripmate, don't let this combo go by.
Dealing with Maps
If you have a laptop with a color screen and the Delorme Street Atlas program, you're all set for GPS navigation. The whole operation is almost plug-n-play. On the other hand, if you want to use the Palmtop, you'll have to create your own black and white versions of the maps you want to use. You can begin by exporting the maps from Street Atlas. That's the easy part. Trying to get something that looks good on the Palmtop is time consuming and frustrating.
For example, if you capture a map on your desktop or laptop computer and load it into a program such as Paint Shop Pro, convert it to grey scale and then decrease the colors to 2 bits, you'll wind up with something that is unreadable. Red colored streets on a yellow background look like fuzzy lines on a fuzzy background. The trick is to zoom in on the map and mark all the yellow regions with the "penlight" icon. Then use the flood-fill paint can to color these regions white. Now try adjusting the contrast and reducing the colors to a two bit image. Paint Shop Pro will remember your settings and you can create a lot of maps with the same settings. (You might want to jot down the numbers for each setting in case you change the settings for another project. You can key in the numbers rather than using sliders and scroll buttons.) Note that you don't have to reverse the black and white colors of the map. LXGPS will do that for you automatically.
After tinkering with coloring programs for several hours, I was able to get a readable B/W map of most of Travis County, Texas (about 35 miles across). I started by setting the color display to 800 x 600 resolution and used the PrintScreen key to capture a map that would fill almost seven screens on the Palmtop. The resulting map included most of the major roads and streets in metropolitan Austin. When I captured the map, I also inserted two tiny diamonds at opposing corners of the screen, and copied the latitude/longitude down to the four decimal places of the seconds value of each of these. That really helps with the calibration of the map for use with the LXGPS program.
It's extremely important that you perform map calibration "by the book." There are several steps to follow and it's critical that you perform them in the correct sequence. If you don't, you'll either get no results or, worse yet, the LXGPS program will give you a "floating point divide" error and crash. On the other hand, if you follow the directions in the LXGPS documentation, you'll be able to calibrate the map quickly. The LXGPS calibration marker can move around the screen in large jumps or be fine-tuned to move one pixel at a time.
For me, the result of all this effort was mind boggling. The display accuracy was such that, on roads marked by two lanes, I could look at the Palmtop's display and tell on which side of the road I was located. I could watch as I approached an overpass and see the on-screen marker touch the overpass on the display.
Copyright © 2010 Thaddeus Computing Inc