ncl_mapblm (3) - Linux Manuals

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

C-BINDING SYNOPSIS

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

USAGE

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

ACCESS

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