Subroutine:	IRCO_PRNAME.

 Purpose: 	Give full name to plate projection system number.

 File: 	irco_project.shl.

 Author:	85 Jun 24 Albrecht de Jonge.

 Use:	<array> = IRCO_PRNAME (
		PRID 	I	integer.
		)
       <array>	(function result) a character string giving a
		proper description of the projection system.
		Function returns a blank if (PRID < 1) or
		(PRID > mxprid).
	PRID	a projection system number.
 Description:
	Projection methods for the celestial sphere, used in subroutines
	IRCO_PROJECT, are numbered as follows:
	
	    1  'STEREO Stereographic'             conformal azimuthal
	    2  'GNOMON Gnomonic/Tangent plane'
	    3  'AZEQD  Azimuthal equidistant'
	    4  'AZEQA  Azimuthal equal area'
	    5  'ORTHO  Orthographic'             sphere seen from infinity
	    6  'CYLIND Cylindrical eq.area'
	    7  'MERCAT Mercator'                  cylindrical conformal
	    8  'SINUS  Sinusoidal eq.area'
	    9  'AITOFF Hammer-Aitoff eq.area'
	   10  'CYLEQD cylindrical equidistant'
	
	This function IRCO_PRNAME gives both a character form suitable for
	keywords ( return value (1:6)),
	and one for documentation of printouts etc (return value (8:)).
	
	At most 30 characters in total will be returned to you.
 References:
	 IRCO_PROJECT.
 Updates:
	90 Apr 25 Sjag Steensma; documentation changed,
	88 Jan 13 Peter Arendz; standarized,
	87 May 18 Albrecht de Jonge; renamed,
	87 Jan 21 Do Kester; added another projection.