Mapping Hacks

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Chapter 3, Mapping Your World

#25 Work with Multiple Lat/Long Formats

HACK

with World Wind. There is no SourceForge repository for it, but there is an

active community in their forums, located at http://learn.arc.nasa.gov/

worldwind/forums/. Thanks to Moore’s Law, we now have the ability to play

this data back on the hardware on our desktop. How far we have come from

vellum and quill pens!

—Adam Hill

HACK

#25

Work with Multiple Lat/Long Formats Hack #25

While latitude and longitude stay constant, their representations don’t. You

can still use new data with a traditional map, if you know a few key

conversions.

Even the novice cartographic hacker has noticed that there are at least three

common ways to represent latitude and longitude, and at least two conven-

tions for direction. Traditionally, mariners use degree-minute-second (DMS)

notation. Computer types find decimal degrees easier to process, and, just to

make life more interesting, some people write coordinates with integer

degrees and minutes in decimal form. Your GPS receiver may use one style

by default, and your mapping tools or your waypoint listing may use

another, which can lead to inconvenience and confusion. Fortunately, this

situation is pretty easy to deal with.

Latitude and longitude, of course, are just x- and y-coordinates on a great

spherical grid that covers the world. Lines of latitude, referred to as parallels

(because they