kpgPutOutline

Create and store an STC polygon describing the spatial extent of an NDF

Description:

If the NDF is 3D it is collapsed onto the spatial pixel axes (which must be pixel axes 1 and 2), and all pixels with less than the specified fraction of good values in each pixel are set bad. An AST Polygon is then created describing the good values in the collapsed array. This polygon is mapped into the SKY Frame and converted to an STC-S description, which is stored in an extension called " OUTLINE" in the supplied NDF (the extension is a character array).

Invocation

void kpgPutOutline( int indf, float wlim, int convex, int ∗status )

Arguments

indf = int (Given)
Identifier for the NDF. Must be 2-D or 3-D. The WCS must contain a SkyFrame, and the first two pixel axes must map onto the two sky axes.
wlim = float (Given)
Minimum fraction of good values per pixel required when collapsing a 3D NDF. Ignored if the NDF has only two significant pixel axes.
convex = int (Given)
Indicates the nature of the polygon. If zero, the polygon will be a simple outline that hugs the edges of the good pixels. If the NDF contains multiple dis-contiguous regions of good pixels, the outline will be of a randomly selected contiguous clump of good pixels. If " convex" is non-zero, the polygon will be the shortest polygon that encloses all good pixels in the NDF. Such a polygon will not in general hug the edges of the good pixels.
status = int ∗ (Given and Returned)
Pointer to global status.