NAME

mcon - merge context information from several EIS context files

USAGE

mcon conims

PARAMETERS

conims = "*context*.hhh" [file name template]

The list of context image files which are to have their context information merged. This can either be a comma delimited list, a template using wild cards or a text file specified using the "@" syntax.

(mascon = "MCONTAB") [file name]

The name for a text file into which the final full merged context table will be written. This contains information about all the contexts found in all the supplied context images.

DESCRIPTION

This task is for merging context information from different context images to create a master context list and to update the context images to reflect the contents of this list. This is normally run after a set of image coadditions have been done using drizzle. In such as case context numbers appropriate to each individual output image will have been allocated but, as they have no knowledge of each other, they will not be the same - in one output "context 1" will be different from in another. MCON solves this problem in the following steps:

i)    The context tables are read one by one from all the input context images.

ii)   These are then merged into a master context list in which all the
      contexts present are allocated a unique number.

iii)  This master context list is written to a text file with the name
      specified by the "mascon" parameter (default value MCONTAB).

iv)   The headers of the input context images are updated to contain the
      entries in the master context table which are found in that image.

v)    The values in each context image are updated to reflect the changes.

When this process is complete the meaning of a context can be looked up in the header of the context image (where the number of pixels in that image having this value will be recorded) or in the master context text table (where the total number of pixels having this context in all the context images will be recorded).

In order to avoid excessively long headers the "header context table" is actually stored in a text file when there are more than a specified (currently 20) number of contexts appropriate to that image. These table files normally are named <context image name>.CON and should not be deleted or separated from there parent image files.

EXAMPLE

To merge the contexts of all the context images in the current directory:

mcon "*context.hhh" 

In this case the master context table will have the default name MCONTAB.

BUGS

None known, but I bet there are some - the logic of this task is rather complicated.

TIMING

About 20s total elapsed time for 6 2000x2000 input images and a total of 23 contexts on a SUN Ultra 10/300 (Iraf 2.11.1, Solaris 2.5.1).

SEE ALSO

drizzle,parapredriz,pcon,gcon