NAME

       MAPBLM - Draws geographical outlines masked against an existing area map.  Note that this
       routine uses whichever old outline dataset is selected by the value of the internal
       parameter 'OU'; to access the new map database "Earth..1", which was created in 1998, one
       must call instead the EZMAPB routine MPLNDM.

SYNOPSIS

       CALL MAPBLM (IAMA,XCRA,YCRA,MCRA,IAAI,IAGI,MNOG,ULPR)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_mapblm (int *iama, float *xcra, float *ycra,
       int mcra, int *iaai, int *iagi, int mnog,
       int (*ulpr)(float *xcra, float *ycra, int *ncs,
       int *iaai, int *iagi, int *nai))

DESCRIPTION

       IAMA        (an input/output array, dimensioned as specified in a call to the AREAS
                   routine ARINAM, of type INTEGER) is the array containing the area map against
                   which boundary lines are to be masked. The area map must have been initialized
                   by a call to ARINAM; it should contain the edges required to create a desired
                   effect.  For example, an area map might be created that defines a region of
                   interest, within which user data is available and within which boundary lines
                   are to be drawn. For more details, see the reference document for the package
                   named AREAS.

       XCRA and YCRA
                   (scratch arrays, dimensioned at least MCRA, of type REAL) are to be used by
                   MAPBLM in calls to the AREAS routine ARDRLN; they will eventually be used in
                   calls to the user-provided line-processing routine ULPR.

       MCRA        (an input expression of type INTEGER) is the dimension of the arrays XCRA and
                   YCRA.

       IAAI and IAGI
                   (scratch arrays, dimensioned at least NOGI, of type INTEGER) are to be used by
                   MAPBLM in calls to the AREAS routine ARDRLN; they will eventually be used in
                   calls to the user-provided line-processing routine ULPR. The mnemonics stand
                   for "Integer Array of Area Identifiers" and "Integer Array of Group
                   Identifiers", respectively.

       NOGI        (an input expression of type INTEGER) is the dimension of the arrays IAAI and
                   IAGI. The mnemonic stands for "Number Of Group Identifiers (of edges in the
                   area map)", which determines the required dimension of IAAI and IAGI.

       ULPR        is the name of the user-supplied line-processing routine. It must be declared
                   EXTERNAL in the routine that calls MAPBLM, so that the compiler and loader
                   will know that it is the name of a routine to be called instead of a variable.
                   The user routine ULPR will be called once for each piece of a boundary line
                   resulting from the masking process; it may decide to draw (or to not draw)
                   each such piece. ULPR will be called using a FORTRAN statement like

                        CALL ULPR (XCRA,YCRA,NCRA,IAAI,IAGI,NGPS)

                   where XCRA and YCRA are real arrays holding the normalized device coordinates
                   of NCRA points defining a polyline which is part of some boundary line and
                   IAAI and IAGI are integer arrays holding NGPS area-identifier/group-identifier
                   pairs for the area within which that piece of the line lies. In writing ULPR,
                   the user may rely upon a SET call's having been done which makes it possible
                   to use normalized device coordinates in calls to routines like CURVE, CURVED,
                   GPL, etc. For more details, see the reference document for the package named
                   AREAS and, in particular, the description of the subroutine ARDRLN.

C-BINDING DESCRIPTION

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

USAGE

       The statement

            CALL MAPBLM (IAMA,XCRA,YCRA,MCRA,IAAI,IAGI,MNOG,ULPR)

       does the same thing as the statement

            CALL MAPLOT

       except that the boundary lines are drawn using calls to MAPITM and MAPIQM, which does the
       masking of the lines against the area map defined by the arguments in the call and passes
       the pieces resulting from the masking process to a user-provided line-drawing routine.

EXAMPLES

       Use the ncargex command to see the following relevant example: cpex10.

ACCESS

       To use MAPBLM or c_mapblm, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c,
       preferably in that order.

SEE ALSO

       Online: ezmap, ezmap_params, mapaci, mapbla, mapdrw, mapeod, mapfst, mapgci, mapgrd,
       mapgrm, mapgtc, mapgti, mapgtl, mapgtr, mapint, mapiq, mapiqa, mapiqd, mapiqm, mapit,
       mapita, mapitd, mapitm, maplbl, maplmb, maplot, mappos, maproj, maprs, maprst, mapsav,
       mapset, mapstc, mapsti, mapstl, mapstr, maptra, maptri, maptrn, mapusr, mapvec, mpchln,
       mpfnme, mpgetc, mpgeti, mpgetl, mpgetr, mpglty, mpiaty, mpifnb, mpilnb, mpiola, mpiosa,
       mpipai, mpipan, mpipar, mpisci, mplnam, mplndm, mplndr, mplnri, mpname, mprset, mpsetc,
       mpseti, mpsetl, mpsetr, supmap, supcon, ncarg_cbind

       Hardcopy: NCAR Graphics Contouring and Mapping Tutorial

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.