This program converts a cube in camera coordinates to a map projection. The input cube requires SPICE data and therefore
the program "spiceinit" should be run on it prior to "vims2map". The map
projection is defined using a PVL file specificied through the MAP
parameter. The system default is to use the Sinusoidal projection
($ISIS3DATA/base/templates/maps/sinusoidal.map).
If you need to generate your own map file you can use the "maptemplate" program or alternatively, hand create a file using your favorite editor.
The map file need only specify the ProjectionName as defaults will be computed for the remaining map file parameters. The following table
indicates how the defaults are established:
| PARAMETER |
DEFAULT |
| TargetName |
Read from Instrument group in the input cube labels |
EquatorialRadius
PolarRadius |
Read from SPICE pck file set during spiceinit. The pck file is defined in the Kernels group via the TargetAttitudeShape keyword |
| LatitudeType |
Planetocentric |
| LongitudeDirection |
PositiveEast |
| LongitudeDomain |
Normally, 360. However, if the cube crosses the longitude boundary the value will change to 180 |
MinimumLatitude
MaximumLatitude
MinimumLongitude
MaximumLongitude |
Computed from the input cube or read from the map file. However, any combination of the four values can then be overridden by the user |
PixelResolution
Scale |
Computed from the input cube or read from the map file. The value can be overridden by the user. |
If you only entered the input cube (FROM) and output cube (TO) and changed no other parameters the following is the default Mapping group:
Group = Mapping
TargetName = Obtained from the Instrument group
EquatorialRadius = Obtained from TargetAttitudeShape kernel
PolarRadius = Obtained from TargetAttitudeShape kernel
LatitudeType = Planetocentric
LongitudeDirection = PositiveEast
LongitudeDomain = 360 (Could be automatically adjusted to 180 by LONSEAM)
MinimumLatitude = Computed from the input camera cube
MaximumLatitude = Computed from the input camera cube
MinimumLongitude = Computed from the input camera cube
MaximumLongitude = Computed from the input camera cube
ProjectionName = Sinusodial
CenterLongitude = Average of MinimumLongitude and MaximumLongitude
PixelResolution = Computed from the input camera cube
EndGroup
Note that an important concept here is the map file can come from an existing map projected cube.
Because the cube has PVL labels and contains the Mapping group, you can essentially force
the input camera cube to have the same mapping parameters and/or selectively use some of the components of the cube's mapping group.
If you are attempting to construct a mosaic, it is important that the PixelResolution, EquatorialRadius, PolarRadius, LatitudeType,
LongitudeDirection, LongitudeDomain, ProjectionName, and projection specific parameters (e.g., CenterLongitude, CenterLatitude) are the same for all cubes. That is, you should
create one map file and use it as input for all the cubes in your mosaic.
However, the ground range (MinimumLatitude, MaximumLatitude, MinimumLongitude, MaximumLongitude) should not be entered or you will create projected images
with large amounts of NULL pixels. The following Mapping group could be used for mosaicking:
Group = Mapping
ProjectionName = Sinusodial
CenterLongitude = 0
PixelResolution = 100 <meters>
EndGroup
Finally, depending on the projection, problems can occur with cubes that fall on the projection longitude seam. For example, if you are making a mosaic with LongitudeDomain = 360 and
your cube crosses 0/360 seam, this program would compute the default longitude range of the cube to MinimumLongitude = 0 and MaximumLongitude = 360. A very large output image
could be created depending on the pixel resolution. The LONSEAM parameter allows you to selectively handle this case. If you are making mosaics near the seam you will need to
understand and alter the default for this parameter.
