GProjUTM Class Reference

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class for UTM projection. More...

#include <src/gproj.h>

Inherits: GMapProj

Public Members

Protected Members


Detailed Description

UTM projection divides the Earth between lats. 84N and 80S into 60 zones. The scal along central meridian is reduced to 0.9996. In the northern Hemisphere, the Equator at the central meridian is considered the origin, with an x coordinate of 500,000 m and a y of 0. For the southern Hemisphere the same point is the origin, but while x remains same 500,000m, the y is 10,000000. IN each case numbers increase toward east and north thus to avoid negative values. For each point on the Earth, its position is uniquely determined by the (x,y) coordinates plus the zone number.


NOP GProjUTM() [public]

Default constructor; must call init() before any conversion.

NOP GProjUTM(double r_maj, double r_min, int _zone) [public]

construct a UTM projection with major/minor axis and zone number. If the projection is applied to Southern Hemishpere then the value of _zone should be negative (ie -55 instead of 55 for part of Australia).

NOP GProjUTM(const GEllipsoid& e, int _zone) [public]

same as previous constructor; uses a handy form of parameter.

Result init(double r_maj, double r_min, int _zone) [public]

initialize for the UTM projection. Must be called before any foward/inverse conversion can happen.

Result forward(double lon, double lat, double& x, double& y) [public]

Forward conversion from (longitude,latitude) to UTM coordinates in meters.

Parameters:
(lon, lat) MUST be *radians* !!!

Result inverse(double x, double y, double& lon, double& lat) [public]

Inverse conversion from UTM coordinates to (longitude, latitude). (x,y) must be in meters; and (lon, lat) will be in *radians*.


Documentation generated by lqian@lqian-sun on Wed Jul 14 09:36:10 EDT 1999
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