Understanding Map Projections
Understanding Map Projections
Understanding Map Projections
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
GEOCENTRIC COORDINATE SYSTEM<br />
Geographic coordinates are described as X,Y, and Z values in a<br />
geocentric coordinate system.<br />
DESCRIPTION<br />
The geocentric coordinate system is not a map<br />
projection. The earth is modeled as a sphere or<br />
spheroid in a right-handed X,Y,Z system.<br />
The X-axis points to the prime meridian, the Y-axis<br />
points 90 degrees away in the equatorial plane, and<br />
the Z-axis points in the direction of the North Pole.<br />
USES AND APPLICATIONS<br />
The geocentric coordinate system is used internally<br />
as an interim system for several geographic (datum)<br />
transformation methods.<br />
58 • <strong>Understanding</strong> <strong>Map</strong> <strong>Projections</strong>