Level 2 Help for RPC_FIT

This is the image to be map projected. It is in the raw instrument space.
For example, this might be a Quickbird image. This should be in VICAR
format.

This image should contain metadata describing the initial RPC. For VICAR,
this is a GeoTIFF label with RPC.

This is the reference image. This should be a map projected image, and 
contain metadata describing the map projection. For example, this might be
a CIB image. This provides ground truth.

This should be in VICAR format.

This is the Digital Elevation Model (DEM). This should be map projected
and contain metadata describing the map projection. 

This gives the height of the surface in meters relative to a reference
surface (usually Mean Sea Level WGS84).

This should be in VICAR format.

This is the land/water mask. This should be map projected and contain
metadata describing the map projection.

This should be in VICAR format.

Maximum difference between initial warp of INP and REF_IMAGE, in meters.
This is used for determining the window size used in the initial iteration 
of the matching, so this should be an overestimate of the differences.

This gives the parameters of the line numerator term of the RPC that we
will fit for. These should be numbers from 0 to 19. The default is to fit
for the constant term (term 0) and the height term (term 3).

This gives the parameters of the sample numerator term of the RPC that we
will fit for. These should be numbers from 0 to 19. The default is to fit
for the constant term (term 0) and the height term (term 3).