subsamp - creates datasets with subsampled variables

subsamp - Creates datasets with subsampled variables

SYNOPSIS

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

Parameters are: include_vars, dim_deltas, dim_starts, dim_counts.

DESCRIPTION

subsamp subsamples variable data based on user specified deltas, starts, and counts. All variables must have the same dimensions.

If variable V has values V(1), V(2), ..., then the output variable W will have values W(i) = V(start + (i-1)*delta), 1 <= i <= count. The default 1-relative start is delta/2 +1.

dim_starts and dim_counts are optional parameters, meaning they must be specified on the command line in order to override their default values.

PARAMETERS

include_vars

List of variables to subsample. If the list is prefixed by a minus sign, then all variables except those listed will be subsampled.

dim_deltas

List of subsample deltas. The number of deltas must be the same as the number of variable dimensions. For example, to subsample 2-D data, there must be two deltas. The maximum delta is 100. There is no default response.

dim_starts: OPTIONAL. 1-relative start coordinate of subsample in the input. For each dimension, the default is delta/2 +1.

dim_counts: OPTIONAL. Size of each subsampled dimension. For each output dimension, the default is 0, which means the size will be computed as (input size + delta/2 +1 - start)/delta.

EXAMPLES

This is an example of subsampling all the variables with the same dimension in a dataset. This actually shrinks the image and is used before running llcontr2.

\fCcabo% subsamp
in/out files   : char(255) ? n12.93273.1708 n12.subsamp
include_vars   : char(255) ? [] *ch*
dim_deltas     : int (  5) ? 4 4
cabo%

This is a list of the variable dimensions from the contents of the original dataset.

\fCVariable        Dimension       Size
 hrpt_header     line            3808
 hrpt_header     dim_2            103
 avhrr_ch1       line            3808
 avhrr_ch1       sample          2048
 avhrr_ch2       line            3808
 avhrr_ch2       sample          2048
 avhrr_ch3       line            3808
 avhrr_ch3       sample          2048
 avhrr_ch4       line            3808
 avhrr_ch4       sample          2048
 avhrr_ch5       line            3808
 avhrr_ch5       sample          2048

This is a list of the variable dimensions from the contents of the subsampled output dataset.

\fCVariable        Dimension       Size
 avhrr_ch1       line             951
 avhrr_ch1       sample           511
 avhrr_ch2       line             951
 avhrr_ch2       sample           511
 avhrr_ch3       line             951
 avhrr_ch3       sample           511
 avhrr_ch4       line             951
 avhrr_ch4       sample           511
 avhrr_ch5       line             951
 avhrr_ch5       sample           511