GR - Multifile General Raster Image Interface

GRattrinfo/mgatinf	Retrieves information about an attribute.
GRcreate/mgcreat	Creates a new raster image.
GRend/mgend	Terminates the GR interface session.
GRendaccess/mgendac	Terminates access to a raster image.
GRfileinfo/mgfinfo	Retrieves the number of raster images and the number of global attributes in the file.
GRfindattr/mgfndat	Finds the index of a data object's attribute given an attribute name.
GRgetattr/mggnatt/mggcatt	Reads the values of an attribute for a data object.
GRgetchunkinfo/mggichnk	Raster image identifier returned by GRcreate or GRselect
GRgetiminfo/mggiinf	Retrieves general information about a raster image.
GRgetlutid/mggltid	Gets the identifier of a palette given its index.
GRgetlutinfo/mgglinf	Retrieves information about a palette.
GRidtoref/mgid2rf	Maps a raster image identifier to a reference number.
GRluttoref/mglt2rf	Maps a palette identifier to a reference number.
GRnametoindex/mgn2ndx	Maps the name of a raster image to an index.
GRreadimage/mgrdimg/mgrcimg	Raster image identifier returned by GRcreate or GRselect
GRreadlut/mgrdlut/mgrclut	Reads a palette.
GRreftoindex/mgr2idx	Maps the reference number of a raster image to an index.
GRreqimageil/mgrimil	Specifies the interlace mode to be used in the subsequent raster image read operation(s).
GRreqlutil/mgrltil	Specifies the interlace mode to be used in the next palette read operation(s).
GRselect/mgselct	Selects the existing raster image.
GRsetattr/mgsnatt/mgscatt	Assigns an attribute to a raster image or a file.
GRsetcompress/mgscompress	Specifies if the raster image will be stored in a file as a compressed raster image.
GRsetchunk/mgschnk	Makes a raster image a chunked raster image.
GRsetchunkcache/mgscchnk	Specifies the maximum number of chunks to cache.
GRsetexternalfile/mgsxfil	Specifies that the raster image will be written to an external file.
GRstart/mgstart	Initializes the GR interface.
GRwriteimage/mgwrimg/mgwcimg	Writes a raster image.
GRwritelut/mgwrlut/mgwclut	Writes a palette.