### MOCGEN

Creates a Multi-Order Coverage map describing regions of an image

#### Description:

This application creates a Multi-Order Coverage (MOC) map describing selected regions of the sky, using the scheme described in Version 1.1 of the MOC recommendation published by the International Virtual Observatory Alliance (IVOA).

The regions of sky to be included in the MOC may be specified in several ways (see Parameter MODE).

#### Usage:

mocgen in out mode

#### Parameters:

The NDF component to be used if Parameter MODE is "Good" or "Bad". It may be "Data" or "Variance". ["Data"]
The format to use when generating the output MOC specified by Parameter OUT.
• "FITS" –- The output MOC is stored as a binary-table extension in a FITS file, using the conventions described in Version 1.1 of the IVOA’s MOC recommendation.

• "AST" –- The output MOC is stored as a text file using native AST encoding.

• "String" –- The output MOC is stored as a text file using the "string" encoding described in Version 1.1 of the IVOA’s MOC recommendation.

• "JSON" –- The output MOC is stored as a text file using the JSON encoding described in Version 1.1 of the IVOA’s MOC recommendation.

["FITS"]

The input NDF. Must be two-dimensional.
The size of the smallest cells in the returned MOC, in arcseconds. The nearest of the valid values defined in the MOC recommendation is used. The default value is the largest legal value that results in the cells in the MOC being no larger than the size of the pixels in the centre of the supplied NDF. [!]
The size of the largest feature that may be missed in the supplied NDF, in arcseconds. It gives the resolution of the initial grid used to identify areas that are inside the MOC. Bounded ’holes’ or ’islands’ in the NDF that are smaller than one cell of this initial grid may be missed (i.e. such holes may be ’filled in’ and islands omitted in the resulting MOC). The default value is 16 times Parameter MaxRes. [!]
The mode used to specify the sky regions to include in the output MOC.
• "Good" –- The output MOC contains the good pixels in the input NDF specified by Parameter IN.

• "Bad" –- The output MOC contains the bad pixels in the input NDF specified by Parameter IN.

• "Qual" –- The output MOC contains the pixels that have the quality specified by Parameter QEXP within the input NDF specified by Parameter IN.

["Good"]

##### OUT = FILENAME (Write)
Name of the file in which to store the MOC description of the selected regions. The format to use is specified by Parameter FORMAT. If Parameter FORMAT is "FITS", ".fits" is appended to the supplied file name, provided no other file type is included in the supplied string.
The quality expression. Only used if Parameter MOD is "QUAL".
USEAXIS is only accessed if the current co-ordinate Frame of the NDF has too many axes. A group of strings should be supplied specifying the axes which are to be used. Each axis can be specified using one of the following options.
• Its integer index within the current Frame of the input NDF (in the range 1 to the number of axes in the current Frame).

• Its Symbol  string such as "RA" or "VRAD".

• A generic option where "SPEC" requests the spectral axis, "TIME" selects the time axis, "SKYLON" and "SKYLAT" picks the sky longitude and latitude axes respectively. Only those axis domains present are available as options.

A list of acceptable values is displayed if an illegal value is supplied. If a null (!) value is supplied, the axes with the same indices as the two used pixel axes within the NDF are used. [!]

#### Examples:

mocgen m31 m31.fits
Generates a a MOC description of the good pixels in NDF "m31", storing the MOC as a binary table in FITS file "m31.fits".