Eblo

Plotting GPS Tracks (Was: How'd you do that???)

Updated 6/15/04. Important updates should be obvious. Unimportant ones shouldn't be.

I get asked a lot about how I plotted my ground tracks from my flight lessons. I figured I'd copy the response here in case I'm asked again. Hopefully I'll flesh it out as time goes on.

Doing the plots is simple in a way, but actually involves a few steps.

1) Track the flight: I do this by firing up my handheld GPS and throwing it in the back seat of the Warrior. Most of the time it tracks just fine. Occasionally, I lose the sats for a bit and I get random glitches in the track. If they aren't major, they can be easily fixed in one of the following steps.

2) Dump the track from the GPS: I use a program called Expert GPS to download the tracks/waypoints/etc. from my Garmin to my laptop. There are many programs out there. This one has some advantages and some disadvantages. I should write up a full review of it one day, but the killer-app of this program is that it'll automatically download aerial photo or topo-map backgrounds for your maps. You can zoom in pretty close, too. ExpertGPS has a free trial and then is cheap after that. Here's their website: expertgps.com

3) (Optional) Scan in and calibrate the sectional: If an aerial photo background is good enough, I can skip this step. If I want to show the sectional, I have to scan it in. The tough thing is stitching together a few scans (which I haven't bothered doing yet). Apparently raster files are available from the FAA, but you have to buy a whole subscription, which is $200

UPDATE: Instead of making or buying your own sectional scans, someone was kind enough to post them on the internet: here. TAC charts are also available there.

4) Once it's looking good, capture the image. UPDATE: This used to be tricky, but since version 1.3.5 of ExpertGPS, there is now an 'Export Image' menu item on the Map menu. From there, you can export to a printer or a file.

5) Publish: UPDATE: I now use the program called Gallery to keep all of my images in order. Uploading to my server is handled through that interface.

All of the front end stuff is done in Windows. Gallery runs on my linux server.

It's not bad if I do one or two at a time. But if I let the tracks pile up, it becomes tedious.

If you have any questions, or perhaps suggestions to make the process easier, let me know in the comments section below.