Mapping Hacks

Map Your Tracklogs on the Web #42

Chapter 4, Mapping (on) the Web

|

189

HACK

Hacking Other Projections

“This is all well and good,” you may be thinking, “but what if I want to plot

points in JavaScript on maps that aren’t in a rectangular projection?” Well,

that’s a little bit more of a challenge. For some projections, like the sinusoi-

dal projection, the math still isn’t that hard, and JavaScript can pull it off.

For others, even seemingly simple projections like the Mercator, the amount

of time you’ll spend writing the conversion, or the amount of time the cli-

ent-side will spend performing it, may outweigh the benefits of doing such a

calculation in the web browser.

Consider this, however: if your server-side scripts permit you to populate a

JavaScript data structure with the latitude and longitudes of a constrained

list of places you’re interested in, why not precalculate the projected coordi-

nates on the server-side, and get the best of both worlds, as it were?

For another way to plot points on a world map, see “Plot Arbitrary Points

on a World Map”

[Hack #29]

HACK

#42

Map Your Tracklogs on the Web Hack #42

GPS Visualizer makes zoomable SVG vector maps of your tracks via a web site.

SVG is a perfect vector format for web mapping. It’s in XML, which allows

you to look at the source code, see how it works, and borrow bits you like.

The SVG Viewer from Adobe is a popular plug-in: your web browser ...