Mapping Hacks

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Chapter 5, Mapping with Gadgets

Once you have a tracklog, you can display it over an aerial photo with Wis-

senbach 3D, 3Dem, or Terra Browser. You can also create an animation of

your journey

[Hack #56]. These are tools that treat the tracklog as a line.

The tool provided at http://www.mappinghacks.com/projects/linkmedia/

[Hack #59] will take a tracklog and a list of timestamps, perhaps representing

the times at which you took pictures, and tell you where you were at those

times. It will also tell you how fast you were going, and what direction you

were going (your heading) based on that tracklog.

Understanding tracklog options. Different GPS units store different numbers of

track points. The basic Garmin Etrex stores 1,536 points, while the Etrex

legend can hold 10,000. The Earthmate BlueLogger has “over 50,000.” How

many points is enough? When I bought my Garmin IIIplus, I was sure that

its 1.44 MB of RAM and 1,900 track points would be enough for me!

I was wrong. See “Don’t Lose Your Tracklogs!”

[Hack #58] for a discussion of

tracklog loggers that can effectively allow you to store an unlimited number

of track points.

Tracklogs are like electronic breadcrumbs. You can usually select how often

you want to drop a crumb. Because the bag is a fixed size, you will run out

of crumbs more quickly if you drop crumbs more frequently. If you have a

basic GPS with 1,500 or so track points, then saving ...