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BINGRP

The purpose of BINGRP is to maintain a dataset grouping array. This optional array defines for every pixel in a binned dataset a group membership number. Grouping can be used to group together pixels to improve statistics in fitting programs.

Three options are currently supported by BINGRP,

CANCEL: Delete any existing grouping array
POLAR: Invoke BINGRP to group spatially using radial/azimuthal binning
ARD: Use a spatial description file to define spatial grouping

Both the modes currently implemented perform spatial grouping. The X,Y plane of a dataset is divided into a number of zones according to user input. Each spatial pixel is assigned a zone number. In the 2-D case the output group number is equal to the zone number, but in datasets of higher dimensionality different X,Y planes have the constant NZONE*(I_PLANE-1) added. The result is that pixels are grouped spatially but retain independence in higher dimensions.

Note that when there are more than 2 dimensions the X and Y axes must be the first two axes - use AXORDER to reorder if this not the case.

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Next: Other Grouping Programs Up: Binned dataset commands Prev: Examples