maptrim

This program trims map projected images and sets valid pixels that fall outside a specified bounding box to NULL. By default, the pixels that fall outside the minimum and maximum latitude and longitude found within the Mapping Group of the input cube's label are set to NULL.

The values entered for minimum and maximum latitude and longitude must be in the same longitude domain, longitude direction, and latitude type as the settings in the input image labels within the Mapping Group. If the values entered are in a different longitude domain, they will be interpreted as the domain setting in the image labels, and the entire output cube could contain only NULL pixels. For example, if the input cube's Mapping Group has a longitude direction of positive east and the user specifies values in west longitude, the longitude direction will be interpreted as positive east.

Selectable Modes to Trim an Image

Option	Result
Trim	The image is resized. The pixel dimensions of the file are retained; therefore, the number of pixels is the same. The pixels that fall outside the default or specified latitude and longitude range are set to NULL.
Crop	The image is resampled and trimmed to the exact latitude and longitude range specified for the bounding box. The pixels that fall outside the specified range are not set to NULL.
Both	The image is resampled and trimmed to the exact latitude and longitude range specified for the bounding box. The pixels that fall outside the bounding box are set to NULL.

Warnings:

Mapping information updated after image is cropped:
When the "crop" or "both" option is used, the keywords MinimumLatitude, MaximumLatitude, MinimumLongitude, and MaximumLongitude are removed from the labels. The values that the uncropped image contains have become inaccurate to use for the cropped image because after an image has been cropped, the UpperLeftCornerX and UpperLeftCornerY keywords, where these values begin, have been updated in the labels. Once the labels are updated, and if displayed with an image viewer, such as qview, the latitude and longitude values can be reported accurately.

Mosaicking cropped images:
The cropped images can be mosaicked into an existing output mosaic file using mapmos, or can be included in the input file list for automos. If automos is used, the "grange=user" parameter may have to be entered along with the latitude and longitude range of the mosaic depending on the ISIS version. The option to automatically determine the minimum and maximum latitude and longitude range from the input list in automos may be used but the Mapping Group will only have the UpperLeftCornerX and UpperLeftCornerY keywords.

Note: This application does not handle non-projected images (i.e. images that are not Level2 or a mosaic). To trim a Level1 image, please refer to camtrim.

This example illustrates how to trim a cube that is projected to a sinusoidal projection. All pixels that have latitudes less than 15° or greater than 20° and longitudes less than 222° or greater than 230° are set to NULL. The TRIM option is used since no option is selected.

maptrim FROM=input.cub TO=trimmed.cub MINLAT=15 MAXLAT=20 MINLON=222 MAXLON=230

input.cub

Input cube Parameter Name: FROM This is the input cube to trim.

trimmed.cub

Output cube Parameter Name: TO This is the trimmed cube. Notice that all pixels that fell outside the user-specified range were set to NULL.

This example illustrates how to trim a cube that is projected to a sinusoidal projection. The first part will crop the image to a specified bounding box, and the second part will set pixels outside the bounding box to NULL.

maptrim FROM=LMMP_SAB_sinu.cub to=sinu_crop.cub mode=crop minlat=-60.5836 maxlat=-60.3129 minlon=-161.07 maxlon=-160.377

input.cub

Input cube Parameter Name: FROM This is the input cube to trim.

sinu_crop.cub

Output cube Parameter Name: TO This is the cropped cube. Notice that only the specified bounding box was extracted out of the input cube.

sinu_both.cub

Output cube Parameter Name: TO The image cube shown above was cropped and trimmed to create the image cube shown on the left. Notice that all the pixels outside the specified latitude and longitude range have been set to NULL in this example. The following command line was used to create this output cube: maptrim from=LMMP_SAB_sinu.cub to=sinu_both.cub mode=both minlat=-60.5836 maxlat=-60.3129 minlon=-161.07 maxlon=-160.377