mastersub - create subsets covering a master file map area

mastersub - Create subsets covering a master file map area

SYNOPSIS

mastersub  [ parameter=value ]  [ inputfile outputfile ]
mastersub  [ parameter=value ]  [ inputfile ... directory ]

Parameters are: include_vars, master_file, master_margin, subset_margin, instantiate.

DESCRIPTION

mastersub creates subsets of input datasets so that the subsets cover a given master file area. Unlike subset which allows users to explicitly clip one or more dimensions, mastersub determines which dimensions to clip and how to clip them in order to get the right coverage.

Like subset, mastersub allows users to specify what variables to include or exclude from the subsets.

Also like subset, mastersub can create subsets without actually copying any variable data. In this case, a subset contains link variables that point back to the corresponding input dataset. Alternatively, subsets can be instantiated, a process that copies the necessary variable data from the input datasets.

PARAMETERS

include_vars: List of variables to include in the output subsets. If the list is prefixed with a minus sign, the listed variables are excluded from the subsets. Wildcards * and ? are allowed. The default is to include all variables.

master_file: Dataset describing the area to be covered by the subset(s). Any dataset with a valid earth transform should work. There is no default.

master_margin: Number of pixels to add to the top/bottom/left/right margins of the master area prior to computing the subsets. The default is 0. Increasing master_margin indirectly increases the sizes of the output subsets.

subset_margin: Number of pixels to add to the top/bottom/left/right margins of the subsets after the coverage computation. The default is 0. Increasing subset_margin directly increases the sizes of the output subsets.

instantiate: Indicates that the variable data is to be copied over to the subsets. Valid responses are [yes, no]. The default is no.

NOTES

mastersub is useful when products for several areas are to be generated from a given pass. The entire pass can be ingested in one step, and then subsets covering the different areas can be created using mastersub.


          +-- mastersub --- processing sequence A
          |
ingest ---+-- mastersub --- processing sequence B
          |
          +-- mastersub --- processing sequence C

The alternative to using mastersub is running the ingest process for each product area.

Given multi-resolution data, mastersub attempts to make all Xsubset dimensions the same length, and all Ysubset dimensions the same length. For example, scale multiplied by size is the same for all subset X dimensions; scale multiplied by size is the same for all subset Y dimensions. This conflicts with the subset_margin parameter described above, causing different subset margins to be used.

Last Update: $Date: 2001/02/05 23:31:07 $