Projection or Coordinate System for a Map

By default, Maptitude uses Auto Projection to pick an appropriate projection, which is always an equal area projection. You may specify another projection or coordinate system for a particular map by using one of the coordinate systems. The projection chosen must have an inverse. However, it is not necessary to include the units, False Easting or False Northing when specifying a projection for a map. The following GISDK functions work with map's projection:

GISDK Function	Description
GetMapProjection	Returns the projection and coordinate system used in a map
SetMapProjection	Sets the projection and coordinate system used in a map
MapCoordToXY	Converts a longitude and latitude coordinate to an XY coordinate in the map's coordinate system, using the map units
MapXYToCoord	Converts an XY coordinate in the map's coordinate system, based on the map units, to a longitude and latitude coordinate

Examples

// Change the Map Projection to Albers Equal Area for the Continental U.S.

map = GetMap()

SetMapProjection(map, "nad83:aea-conus",)

...

// Change the Map Projection to UTM for the New York Metro Area

map = GetMap()

center = Coord(-74000000, 40750000)

SetMapScope(map, Scope(center, 10., 10., 0.))

SetMapProjection(map, "utm", {"lon_0 =-74."})

// Compute local center

local = MapCoordToXY(map, center)