1ARPRAM(3NCARG)                   NCAR GRAPHICS                  ARPRAM(3NCARG)
2
3
4

NAME

6       ARPRAM - Preprocesses an area map that has been initialized by a call
7       to ARINAM and to which edges have been added by calls to AREDAM.
8

SYNOPSIS

10       CALL ARPRAM (MAP,IF1,IF2,IF3)
11

C-BINDING SYNOPSIS

13       #include <ncarg/ncargC.h>
14
15       void c_arpram (int *map, int if1, int if2, int if3)
16

DESCRIPTION

18       Preprocessing an area map is a seven-step process that makes all of the
19       area-identifier information in the area map consistent:
20
21       Step 1:     ARPRAM shortens edge segments whose projections on the X
22                   axis are more than twice as long as the average. ARPRAM
23                   does this by interpolating points along their lengths. This
24                   improves efficiency when executing other parts of the
25                   algorithm.
26
27       Step 2:     ARPRAM locates all intersections of edge segments and
28                   interpolates the intersection points along these edge
29                   segments.  This step can take a lot of time. If you set IF1
30                   nonzero, then pairs of edge segments are examined for
31                   intersections only if one of the pair has a left or a right
32                   area identifier that is zero or negative.
33
34       Step 3:     ARPRAM locates coincident edge segments (edge segments with
35                   identical endpoints).  If two such coincident edge segments
36                   belong to the same group, one of them is removed; if they
37                   belong to different groups, one of them is modified in such
38                   a way that it will appear to be present when looking for
39                   areas defined by edge segments in a particular group, but
40                   absent when looking for areas defined by all edge segments.
41
42       Step 4:     ARPRAM searches for and removes "dangling" edge segments
43                   (those that do not contribute to enclosing any area). This
44                   step is skipped if IF2 is nonzero.
45
46       Step 5:     ARPRAM looks for holes in the areas defined by each edge
47                   group and draws connecting edge segments between the edge
48                   and the hole. This step is skipped if IF3 is nonzero.
49
50       Step 6:     ARPRAM adjusts area identifier information in the area map.
51                   It examines all the edge segments of each area in each
52                   group to see what area identifier should be assigned to the
53                   area, and then makes adjustments.
54
55       Step 7:     Connecting lines that were inserted in step 5 are removed
56                   from the area map.
57
58       You can put edges in an area map, preprocess it, add more edges,
59       preprocess it again, and so on.
60
61       Each of the routines ARDRLN, ARGTAI, and ARSCAM checks to make sure
62       that the area map has been preprocessed since the last time that edges
63       were added to it and, if not, calls ARPRAM; the only advantage to the
64       user of calling ARPRAM directly is to use the time-saving shortcuts
65       specified by the arguments IF1, IF2, and IF3.
66
67       The arguments of ARPRAM are as follows:
68
69
70       MAP         (an input/output array of type INTEGER) - An array
71                   containing an area map that has been initialized by a call
72                   to ARINAM and to which edges have been added by calls to
73                   AREDAM.
74
75                   Note: As part of initializing the area map, ARINAM stores
76                   the dimension of MAP in MAP(1); therefore, the dimension
77                   does not have to be given as an argument in calls to
78                   ARPRAM.)
79
80       IF1         (an input expression of type INTEGER) - If you set IF1
81                   nonzero, ARPRAM checks a pair of edge segments for
82                   intersection only if one of the pair has a left or right
83                   area identifier that is zero or negative. This would be
84                   appropriate for contour lines, which intersect the
85                   perimeter, but do not intersect each other.
86
87       IF2         (an input expression of type INTEGER) - If you set IF2
88                   nonzero, ARPRAM does not check for dangling edges. This
89                   would be appropriate for contour lines, which are known not
90                   to have any such edges. This is not appropriate for Ezmap
91                   boundary lines, because the Ezmap dataset contains some
92                   edge segments (small islands) that are formed by unclosed
93                   curves.
94
95       IF3         (an input expression of type INTEGER) - If you set IF3
96                   nonzero, ARPRAM speeds up the process of adjusting area
97                   identifiers by omitting the consideration of "holes" in the
98                   areas examined. This is appropriate for contour lines as
99                   long as the left and right area identifiers provided at
100                   each contour level are consistent with those provided at
101                   the adjacent levels.
102

C-BINDING DESCRIPTION

104       The C-binding argument descriptions are the same as the FORTRAN
105       argument descriptions.
106

EXAMPLES

108       Use the ncargex command to see the following relevant examples: eezmpa,
109       tareas, tezmpa, fsppoint.
110

ACCESS

112       To use ARPRAM or c_arpram, load the NCAR Graphics libraries ncarg,
113       ncarg_gks, and ncarg_c, preferably in that order.
114

MESSAGES

116       See the areas man page for a description of all Areas error messages
117       and/or informational messages.
118

SEE ALSO

120       Online: areas, areas_params, ardbpa, ardrln, aredam, argeti, argetr,
121       argtai, arinam, armvam, arscam, arseti, arsetr, ncarg_cbind
122
123       Hardcopy: NCAR Graphics Contouring and Mapping Tutorial
124
126       Copyright (C) 1987-2009
127       University Corporation for Atmospheric Research
128       The use of this Software is governed by a License Agreement.
129
130
131
132UNIX                              March 1993                    ARPRAM(3NCARG)
Impressum