1MAPITD(3NCARG) NCAR GRAPHICS MAPITD(3NCARG)
2
6 MAPITD - Draws lines on a map. MAPITD is just like MAPIT, but,
7 ultimately, DASHPACK routines are called instead of DASHCHAR routines.
8
10 CALL MAPITD (RLAT,RLON,IFST)
11
13 #include <ncarg/ncargC.h>
14 void c_mapitd (float rlat, float rlon, int ifst)
16
18 RLAT and RLON
19 (input expressions, of type REAL) specify the latitude and
20 longitude of a point to which the "pen" is to be moved.
21 Both are given in degrees. RLAT must be between -90. and
22 +90., inclusive; RLON must be between -540. and +540.,
23 inclusive.
24 IFST (an input expression, of type INTEGER) is 0 to do a "pen-
26 up" move, 1 to do a "pen-down" move only if the distance
27 from the last point to the new point is greater than 'MV'
28 plotter units, and 2 or greater to do a "pen-down" move
29 regardless of the distance from the last point to the new
30 one.
31
33 The C-binding argument descriptions are the same as the FORTRAN
34 argument descriptions.
35
37 MAPITD is used to draw lines on the map. MAPITD attempts to omit
38 nonvisible portions of lines and to handle "crossover," a jump from one
39 end of the map to the other caused by the projection of the globe onto
40 a flat surface. Crossover can occur on cylindrical and conical
41 projections; MAPITD handles it gracefully on the former and not so well
42 on the latter.
43 To draw the projection of a line defined by a series of lat/lon
45 coordinates, start by calling MAPITD with the coordinates of the first
46 point and with IFST = 0. Then, call MAPITD repeatedly with the
47 coordinates of the next point along the line and with IFST = 1 or 2.
48 (IFST = 2 is normally used only for the final point, to ensure closure
49 with a line drawn by another series of calls.) Finally, if the next
50 thing your program does is STOP, call FRAME, or change attributes like
51 color or line width, you should call MAPIQD to flush MAPITD's buffers.
52 The EZMAP parameter 'DL' determines whether MAPITD draws solid lines or
54 dotted lines. Dotted lines are drawn using calls to POINTS. Solid lines
55 are drawn using calls to DPFRST and DPVECT. The parameters 'DD' and
56 'MV' also affect MAPITD's behavior. See the descriptions of these
57 parameters in the ezmap_params man page.
58 Keep in mind the following:
60 · The projection of the line segment joining two points on the globe
62 is considered to be the straight-line segment joining the
63 projections of the points; no attempt is made to project it as if
64 it were a portion of a great circle.
65 · If both endpoints of a line segment are visible, the segment is
67 considered to be entirely visible.
68 · If both endpoints are invisible, the segment is considered to be
70 entirely invisible.
71 · If one endpoint is visible and the other is not, a new point is
73 interpolated at the boundary between the visible and invisible
74 portions. Only visible portions of the line are drawn.
75 Because of these considerations, points defining a line should not be
77 too far apart on the globe.
78 There are two types of boundaries between visible and invisible
80 regions:
81 · The limb is a boundary between a projectable region and an
83 unprojectable one. The limb may be circular, elliptical, or some
84 other shape, depending on the projection being used. For example,
85 an orthographic projection has as its limb a circle, centered at
86 (0,0), with a radius of 1.
87 · The perimeter is a rectangular or elliptical boundary defined by
89 EZMAP parameters set by you to specify the region you wish to view.
90
92 None.
93
95 To use MAPITD or c_mapitd, load the NCAR Graphics libraries ncarg,
96 ncarg_gks, and ncarg_c, preferably in that order.
97
99 Online: ezmap, ezmap_params, mapaci, mapbla, mapblm, mapdrw, mapeod,
100 mapfst, mapgci, mapgrd, mapgrm, mapgtc, mapgti, mapgtl, mapgtr, mapint,
101 mapiq, mapiqa, mapiqd, mapiqm, mapit, mapita, mapitm, maplbl, maplmb,
102 maplot, mappos, maproj, maprs, maprst, mapsav, mapset, mapstc, mapsti,
103 mapstl, mapstr, maptra, maptri, maptrn, mapusr, mapvec, mpchln, mpfnme,
104 mpgetc, mpgeti, mpgetl, mpgetr, mpglty, mpiaty, mpifnb, mpilnb, mpiola,
105 mpiosa, mpipai, mpipan, mpipar, mpisci, mplnam, mplndm, mplndr, mplnri,
106 mpname, mprset, mpsetc, mpseti, mpsetl, mpsetr, supmap, supcon,
107 ncarg_cbind
108 Hardcopy: NCAR Graphics Contouring and Mapping Tutorial
110
112 Copyright (C) 1987-2007
113 University Corporation for Atmospheric Research
114 This documentation is free software; you can redistribute it and/or
116 modify it under the terms of the GNU General Public License as
117 published by the Free Software Foundation; either version 2 of the
118 License, or (at your option) any later version.
119 This software is distributed in the hope that it will be useful, but
121 WITHOUT ANY WARRANTY; without even the implied warranty of
122 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
123 General Public License for more details.
124 You should have received a copy of the GNU General Public License along
126 with this software; if not, write to the Free Software Foundation,
127 Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
128UNIX March 1993 MAPITD(3NCARG)