17 lines
757 B
GLSL
17 lines
757 B
GLSL
/**
|
|
* The maximum latitude, in radians, both North and South, supported by a Web Mercator
|
|
* (EPSG:3857) projection. Technically, the Mercator projection is defined
|
|
* for any latitude up to (but not including) 90 degrees, but it makes sense
|
|
* to cut it off sooner because it grows exponentially with increasing latitude.
|
|
* The logic behind this particular cutoff value, which is the one used by
|
|
* Google Maps, Bing Maps, and Esri, is that it makes the projection
|
|
* square. That is, the rectangle is equal in the X and Y directions.
|
|
*
|
|
* The constant value is computed as follows:
|
|
* czm_pi * 0.5 - (2.0 * atan(exp(-czm_pi)))
|
|
*
|
|
* @name czm_webMercatorMaxLatitude
|
|
* @glslConstant
|
|
*/
|
|
const float czm_webMercatorMaxLatitude = 1.4844222297453324;
|