1PSMASK(1) GMT PSMASK(1)
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6 psmask - Use data tables to clip or mask map areas with no coverage
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9 psmask [ table ]
10 -Iincrement
11 -Jparameters
12 -Rregion [ -B[p|s]parameters ] [ -Ddumpfile ] [ -F[l|r] ] [ -Gfill
13 ] [ -Jz|Zparameters ] [ -K ] [ -L[+|-]nodegrid ] [ -N ] [ -O ] [
14 -P ] [ -Qcut ] [ -Ssearch_radius[unit] ] [ -T ] [ -U[stamp] ] [
15 -V[level] ] [ -Xx_offset ] [ -Yy_offset ] [ -bibinary ] [ -dinodata ]
16 [ -eregexp ] [ -hheaders ] [ -iflags ] [ -pflags ] [ -r ] [ -ttransp ]
17 [ -:[i|o] ]
18 psmask -C [ -K ] [ -O ]
20 Note: No space is allowed between the option flag and the associated
22 arguments.
23
25 psmask reads a (x,y,z) file [or standard input] and uses this informa‐
26 tion to find out which grid cells are reliable. Only grid cells which
27 have one or more data points are considered reliable. As an option, you
28 may specify a radius of influence. Then, all grid cells that are within
29 radius of a data point are considered reliable. Furthermore, an option
30 is provided to reverse the sense of the test. Having found the reli‐
31 able/not reliable points, psmask will either paint tiles to mask these
32 nodes (with the -T switch), or use contouring to create polygons that
33 will clip out regions of no interest. When clipping is initiated, it
34 will stay in effect until turned off by a second call to psmask using
35 the -C option.
36
38 -Ixinc[unit][+e|n][/yinc[unit][+e|n]]
39 x_inc [and optionally y_inc] is the grid spacing. Optionally,
40 append a suffix modifier. Geographical (degrees) coordinates:
41 Append m to indicate arc minutes or s to indicate arc seconds.
42 If one of the units e, f, k, M, n or u is appended instead, the
43 increment is assumed to be given in meter, foot, km, Mile, nau‐
44 tical mile or US survey foot, respectively, and will be con‐
45 verted to the equivalent degrees longitude at the middle lati‐
46 tude of the region (the conversion depends on PROJ_ELLIPSOID).
47 If y_inc is given but set to 0 it will be reset equal to x_inc;
48 otherwise it will be converted to degrees latitude. All coordi‐
49 nates: If +e is appended then the corresponding max x (east) or
50 y (north) may be slightly adjusted to fit exactly the given
51 increment [by default the increment may be adjusted slightly to
52 fit the given domain]. Finally, instead of giving an increment
53 you may specify the number of nodes desired by appending +n to
54 the supplied integer argument; the increment is then recalcu‐
55 lated from the number of nodes and the domain. The resulting
56 increment value depends on whether you have selected a grid‐
57 line-registered or pixel-registered grid; see App-file-formats
58 for details. Note: if -Rgrdfile is used then the grid spacing
59 has already been initialized; use -I to override the values.
60 -Jparameters (more ...)
62 Select map projection. [Not mandatory when -D].
63 -Rxmin/xmax/ymin/ymax[+r][+uunit] (more ...)
65 Specify the region of interest.
66 For perspective view p, optionally append /zmin/zmax. (more ...)
68
70 table One or more ASCII (or binary, see -bi[ncols][type]) data table
71 file(s) holding a number of data columns. If no tables are given
72 then we read from standard input.
73 -B[p|s]parameters (more ...)
75 Set map boundary frame and axes attributes.
76 -C Mark end of existing clip path. No input file is needed. Implic‐
78 itly sets -O. Also supply -X and -Y settings if you have moved
79 since the clip started.
80 -Ddumpfile
82 Dump the (x,y) coordinates of each clipping polygon to one or
83 more output files (or stdout if template is not given). No plot‐
84 ting will take place. If template contains the C-format speci‐
85 fier %d (including modifications like %05d) then polygons will
86 be written to different files; otherwise all polygons are writ‐
87 ten to the specified file (template). The files are ASCII unless
88 -bo is used. See -Q to exclude small polygons from considera‐
89 tion.
90 -F[l|r]
92 Force clip contours (polygons) to be oriented so that data
93 points are to the left (-Fl [Default]) or right (-Fr) as we move
94 along the perimeter [Default is arbitrary orientation]. Requires
95 -D.
96 -Gfill Paint the clip polygons (or tiles) with a selected fill [Default
98 is no fill].
99 -Jz|Zparameters (more ...)
101 Set z-axis scaling; same syntax as -Jx.
102 -K (more ...)
104 Do not finalize the PostScript plot.
105 -L[+|-]nodegrid
107 Save the internal grid with ones (data constraint) and zeros (no
108 data) to the named nodegrid [no grid saved]. Use L+ to convert
109 the no data flags to NaNs before writing the grid, while L- will
110 instead convert the data flags to NaNs.
111 -N Invert the sense of the test, i.e., clip regions where there is
113 data coverage.
114 -O (more ...)
116 Append to existing PostScript plot.
117 -P (more ...)
119 Select "Portrait" plot orientation.
120 -Q Do not dump polygons with less than cut number of points [Dumps
122 all polygons]. Only applicable if -D has been specified.
123 -Ssearch_radius[unit]
125 Sets radius of influence. Grid nodes within radius of a data
126 point are considered reliable. [Default is 0, which means that
127 only grid cells with data in them are reliable]. Append the dis‐
128 tance unit (see UNITS).
129 -T Plot tiles instead of clip polygons. Use -G to set tile color or
131 pattern. Cannot be used with -D.
132 -U[[just]/dx/dy/][c|label] (more ...)
134 Draw GMT time stamp logo on plot.
135 -V[level] (more ...)
137 Select verbosity level [c].
138 -X[a|c|f|r][x-shift[u]]
140 -Y[a|c|f|r][y-shift[u]] (more ...)
142 Shift plot origin.
143 -bi[ncols][t] (more ...)
145 Select native binary input. [Default is 2 input columns].
146 -dinodata (more ...)
148 Replace input columns that equal nodata with NaN.
149 -e[~]"pattern" | -e[~]/regexp/[i] (more ...)
151 Only accept data records that match the given pattern.
152 -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
154 Skip or produce header record(s). Not used with binary data.
155 -icols[+l][+sscale][+ooffset][,...] (more ...)
157 Select input columns and transformations (0 is first column).
158 -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more ...)
160 Select perspective view.
161 -r (more ...)
163 Set pixel node registration [gridline].
164 -t[transp] (more ...)
166 Set PDF transparency level in percent.
167 -:[i|o] (more ...)
169 Swap 1st and 2nd column on input and/or output.
170 -^ or just -
172 Print a short message about the syntax of the command, then
173 exits (NOTE: on Windows just use -).
174 -+ or just +
176 Print an extensive usage (help) message, including the explana‐
177 tion of any module-specific option (but not the GMT common
178 options), then exits.
179 -? or no arguments
181 Print a complete usage (help) message, including the explanation
182 of all options, then exits.
183
185 For map distance unit, append unit d for arc degree, m for arc minute,
186 and s for arc second, or e for meter [Default], f for foot, k for km, M
187 for statute mile, n for nautical mile, and u for US survey foot. By
188 default we compute such distances using a spherical approximation with
189 great circles. Prepend - to a distance (or the unit is no distance is
190 given) to perform "Flat Earth" calculations (quicker but less accurate)
191 or prepend + to perform exact geodesic calculations (slower but more
192 accurate).
193
195 To make an overlay PostScript file that will mask out the regions of a
196 contour map where there is no control data using clip polygons, use:
197 gmt psmask africa_grav.xyg -R20/40/20/40 -I5m -JM10i -O -K > mask.ps
199 We do it again, but this time we wish to save the clipping polygons to
201 file all_pols.txt:
202 gmt psmask africa_grav.xyg -R20/40/20/40 -I5m -Dall_pols.txt
204 A repeat of the first example but this time we use white tiling:
206 gmt psmask africa_grav.xyg -R20/40/20/40 -I5m -JM10i -T -O -K -Gwhite > mask.ps
208
210 gmt, gmtcolors, grdmask, surface, psbasemap, psclip
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213 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
2145.4.5 Feb 24, 2019 PSMASK(1)