Syntax: projection(obj = VAL [, lat = FLOAT] [, lon = FLOAT] [, rad = FLOAT] [, ppd = INT] [, type = STRING])
The projection() function will process each band of an object, projecting into a BIL organized dataset. Format of the object does not matter.
lat and lon specify the center point of the projection, rad specifies the radius extent of the projection in degrees.
The ppd parameter specifies pixels per degree, and when combined with the radius value, defines the size of the output image. Therefore, if a radius of 20 is specified with ppd=5 the resulting band will be 200 pixels (2x20x5) on each side.
The type parameter sets the parameters of distortion, that is if one is projecting on the planet Mars as opposed to a sphere, there will be a slightly different result. The projection types are as follows:
The four optional parameters default to the following values: