1PSMASK(1) Generic Mapping Tools PSMASK(1)
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6 psmask - To clip or mask areas of no data on a map
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9 psmask [xyzfile] -Ixinc[unit][=|+][/yinc[unit][=|+]] -Jparameters
10 -Rwest/east/south/north[r] [ -B[p|s]parameters ] [ -Ddumpfile ] [
11 -Eazim/elev[+wlon/lat[/z]][+vx0/y0] ] [ -F ] [ -Gfill ] [ -H[i][nrec] ]
12 [ -K ] [ -N ] [ -O ] [ -P ] [ -Ssearch_radius[m|c|k|K] ] [ -T ] [
13 -U[just/dx/dy/][c|label] ] [ -V ] [ -X[a|c|r][x-shift[u]] ] [
14 -Y[a|c|r][y-shift[u]] ] [ -ccopies ] [ -:[i|o] ] [
15 -bi[s|S|d|D[ncol]|c[var1/...]] ] [ -m[flag] ]
16 psmask -C [ -K ] [ -O ]
18
20 psmask reads a (x,y,z) file [or standard input] and uses this informa‐
21 tion to find out which grid cells are reliable. Only gridcells which
22 have one or more data points are considered reliable. As an option,
23 you may specify a radius of influence. Then, all gridcells that are
24 within radius of a data point are considered reliable. Furthermore, an
25 option is provided to reverse the sense of the test. Having found the
26 reliable/not reliable points, psmask will either paint tiles to mask
27 these nodes (with the -T switch), or use contouring to create polygons
28 that will clip out regions of no interest. When clipping is initiated,
29 it will stay in effect until turned off by a second call to psmask
30 using the -C option.
31 xyzfile
33 File with (x,y,z) values (e.g., that was used to run surface).
34 If no file is given, standard input is read. For binary files,
35 see -b.
36 -I x_inc [and optionally y_inc] is the grid spacing. Optionally,
38 append a suffix modifier. Geographical (degrees) coordinates:
39 Append m to indicate arc minutes or c to indicate arc seconds.
40 If one of the units e, k, i, or n is appended instead, the
41 increment is assumed to be given in meter, km, miles, or nauti‐
42 cal miles, respectively, and will be converted to the equivalent
43 degrees longitude at the middle latitude of the region (the con‐
44 version depends on ELLIPSOID). If /y_inc is given but set to 0
45 it will be reset equal to x_inc; otherwise it will be converted
46 to degrees latitude. All coordinates: If = is appended then the
47 corresponding max x (east) or y (north) may be slightly adjusted
48 to fit exactly the given increment [by default the increment may
49 be adjusted slightly to fit the given domain]. Finally, instead
50 of giving an increment you may specify the number of nodes
51 desired by appending + to the supplied integer argument; the
52 increment is then recalculated from the number of nodes and the
53 domain. The resulting increment value depends on whether you
54 have selected a gridline-registered or pixel-registered grid;
55 see Appendix B for details. Note: if -Rgrdfile is used then
56 grid spacing has already been initialized; use -I to override
57 the values.
58 -J Selects the map projection. Scale is UNIT/degree, 1:xxxxx, or
60 width in UNIT (upper case modifier). UNIT is cm, inch, or m,
61 depending on the MEASURE_UNIT setting in .gmtdefaults4, but this
62 can be overridden on the command line by appending c, i, or m to
63 the scale/width value. When central meridian is optional,
64 default is center of longitude range on -R option. Default
65 standard parallel is the equator. For map height, max dimen‐
66 sion, or min dimension, append h, +, or - to the width, respec‐
67 tively.
68 More details can be found in the psbasemap man pages.
69 CYLINDRICAL PROJECTIONS:
71 -Jclon0/lat0/scale (Cassini)
73 -Jcyl_stere/[lon0/[lat0/]]scale (Cylindrical Stereographic)
74 -Jj[lon0/]scale (Miller)
75 -Jm[lon0/[lat0/]]scale (Mercator)
76 -Jmlon0/lat0/scale (Mercator - Give meridian and standard paral‐
77 lel)
78 -Jo[a]lon0/lat0/azimuth/scale (Oblique Mercator - point and
79 azimuth)
80 -Jo[b]lon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
81 -Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and
82 pole)
83 -Jq[lon0/[lat0/]]scale (Cylindrical Equidistant)
84 -Jtlon0/[lat0/]scale (TM - Transverse Mercator)
85 -Juzone/scale (UTM - Universal Transverse Mercator)
86 -Jy[lon0/[lat0/]]scale (Cylindrical Equal-Area)
87 CONIC PROJECTIONS:
89 -Jblon0/lat0/lat1/lat2/scale (Albers)
91 -Jdlon0/lat0/lat1/lat2/scale (Conic Equidistant)
92 -Jllon0/lat0/lat1/lat2/scale (Lambert Conic Conformal)
93 -Jpoly/[lon0/[lat0/]]scale ((American) Polyconic)
94 AZIMUTHAL PROJECTIONS:
96 -Jalon0/lat0[/horizon]/scale (Lambert Azimuthal Equal-Area)
98 -Jelon0/lat0[/horizon]/scale (Azimuthal Equidistant)
99 -Jflon0/lat0[/horizon]/scale (Gnomonic)
100 -Jglon0/lat0[/horizon]/scale (Orthographic)
101 -Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale
102 (General Perspective).
103 -Jslon0/lat0[/horizon]/scale (General Stereographic)
104 MISCELLANEOUS PROJECTIONS:
106 -Jh[lon0/]scale (Hammer)
108 -Ji[lon0/]scale (Sinusoidal)
109 -Jkf[lon0/]scale (Eckert IV)
110 -Jk[s][lon0/]scale (Eckert VI)
111 -Jn[lon0/]scale (Robinson)
112 -Jr[lon0/]scale (Winkel Tripel)
113 -Jv[lon0/]scale (Van der Grinten)
114 -Jw[lon0/]scale (Mollweide)
115 NON-GEOGRAPHICAL PROJECTIONS:
117 -Jp[a]scale[/origin][r|z] (Polar coordinates (theta,r))
119 -Jxx-scale[d|l|ppow|t|T][/y-scale[d|l|ppow|t|T]] (Linear, log,
120 and power scaling)
121 -R xmin, xmax, ymin, and ymax specify the Region of interest. For
123 geographic regions, these limits correspond to west, east,
124 south, and north and you may specify them in decimal degrees or
125 in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left
126 and upper right map coordinates are given instead of w/e/s/n.
127 The two shorthands -Rg and -Rd stand for global domain (0/360
128 and -180/+180 in longitude respectively, with -90/+90 in lati‐
129 tude). Alternatively, specify the name of an existing grid file
130 and the -R settings (and grid spacing, if applicable) are copied
131 from the grid. For calendar time coordinates you may either
132 give (a) relative time (relative to the selected TIME_EPOCH and
133 in the selected TIME_UNIT; append t to -JX|x), or (b) absolute
134 time of the form [date]T[clock] (append T to -JX|x). At least
135 one of date and clock must be present; the T is always required.
136 The date string must be of the form [-]yyyy[-mm[-dd]] (Gregorian
137 calendar) or yyyy[-Www[-d]] (ISO week calendar), while the clock
138 string must be of the form hh:mm:ss[.xxx]. The use of delim‐
139 iters and their type and positions must be exactly as indicated
140 (however, input, output and plot formats are customizable; see
141 gmtdefaults).
142
144 No space between the option flag and the associated arguments.
145 -B Sets map boundary annotation and tickmark intervals; see the
147 psbasemap man page for all the details.
148 -C Mark end of existing clip path. No input file is needed.
150 Implicitly sets -O. However, you must supply -Xa and -Ya set‐
151 tings if you are using absolute positioning.
152 -D Dumps out the resulting clipping polygons to disk. Ignored if
154 -T is set. If no dumpprefix is given we use mask (Files will be
155 called mask_*.d). Append +n<n_pts> to limit the number of
156 points in files to a minimum of n_pts. That is, do not write
157 individual polygon files if they do not have at least n_pts ver‐
158 tices. Often, when one uses the -D option it is not wished to
159 output any ps code to stdout. In such cases redirect the output
160 to > /dev/null on *nix systems or to > nul on Windows.
161 -E Sets the viewpoint's azimuth and elevation (for perspective
163 view) [180/90]. For frames used for animation, you may want to
164 append + to fix the center of your data domain (or specify a
165 particular world coordinate point with +wlon0/lat[/z]) which
166 will project to the center of your page size (or specify the
167 coordinates of the projected veiw point with +vx0/y0).
168 -F Force pixel node registration [Default is gridline registra‐
170 tion]. (Node registrations are defined in GMT Cookbook Appendix
171 B on grid file formats.)
172 -G Paint the clip polygons (or tiles) with a selected fill [Default
174 is no fill]. (See SPECIFYING FILL below).
175 -H Input file(s) has header record(s). If used, the default number
177 of header records is N_HEADER_RECS. Use -Hi if only input data
178 should have header records [Default will write out header
179 records if the input data have them]. Blank lines and lines
180 starting with # are always skipped. Not used with binary data.
181 -K More PostScript code will be appended later [Default terminates
183 the plot system].
184 -N Invert the sense of the test, i.e. clip regions where there is
186 data coverage.
187 -O Selects Overlay plot mode [Default initializes a new plot sys‐
189 tem].
190 -P Selects Portrait plotting mode [Default is Landscape, see gmtde‐
192 faults to change this].
193 -S Sets radius of influence. Grid nodes within radius of a data
195 point are considered reliable. [Default is 0, which means that
196 only grid cells with data in them are reliable]. Append m to
197 indicate minutes or c to indicate seconds. Append k to indicate
198 km (implies -R and -I are in degrees, and we will use a fast
199 flat Earth approximation to calculate distance). For more accu‐
200 racy, use uppercase K if distances should be calculated along
201 geodesics. However, if the current ELLIPSOID is spherical then
202 great circle calculations are used.
203 -T Plot tiles instead of clip polygons. Use -G to set tile color
205 or pattern.
206 -U Draw Unix System time stamp on plot. By adding just/dx/dy/, the
208 user may specify the justification of the stamp and where the
209 stamp should fall on the page relative to lower left corner of
210 the plot. For example, BL/0/0 will align the lower left corner
211 of the time stamp with the lower left corner of the plot.
212 Optionally, append a label, or c (which will plot the command
213 string.). The GMT parameters UNIX_TIME, UNIX_TIME_POS, and
214 UNIX_TIME_FORMAT can affect the appearance; see the gmtdefaults
215 man page for details. The time string will be in the locale set
216 by the environment variable TZ (generally local time).
217 -V Selects verbose mode, which will send progress reports to stderr
219 [Default runs "silently"].
220 -X -Y Shift plot origin relative to the current origin by (x-shift,y-
222 shift) and optionally append the length unit (c, i, m, p). You
223 can prepend a to shift the origin back to the original position
224 after plotting, or prepend r [Default] to reset the current
225 origin to the new location. If -O is used then the default (x-
226 shift,y-shift) is (0,0), otherwise it is (r1i, r1i) or (r2.5c,
227 r2.5c). Alternatively, give c to align the center coordinate (x
228 or y) of the plot with the center of the page based on current
229 page size.
230 -: Toggles between (longitude,latitude) and (latitude,longitude)
232 input and/or output. [Default is (longitude,latitude)]. Append
233 i to select input only or o to select output only. [Default
234 affects both].
235 -bi Selects binary input. Append s for single precision [Default is
237 d (double)]. Uppercase S or D will force byte-swapping.
238 Optionally, append ncol, the number of columns in your binary
239 input file if it exceeds the columns needed by the program. Or
240 append c if the input file is netCDF. Optionally, append
241 var1/var2/... to specify the variables to be read. [Default is
242 2 input columns].
243 -c Specifies the number of plot copies. [Default is 1].
245 -m Multiple segment file(s). Segments are separated by a special
247 record. For ASCII files the first character must be flag
248 [Default is '>']. For binary files all fields must be NaN and
249 -b must set the number of output columns explicitly. By default
250 the -m setting applies to both input and output. Use -mi and
251 -mo to give separate settings to input and output.
252 SPECIFYING FILL
254 fill The attribute fill specifies the solid shade or solid color (see
255 SPECIFYING COLOR below) or the pattern used for filling poly‐
256 gons. Patterns are specified as pdpi/pattern, where pattern
257 gives the number of the built-in pattern (1-90) or the name of a
258 Sun 1-, 8-, or 24-bit raster file. The dpi sets the resolution
259 of the image. For 1-bit rasters: use Pdpi/pattern for inverse
260 video, or append :Fcolor[B[color]] to specify fore- and back‐
261 ground colors (use color = - for transparency). See GMT Cook‐
262 book & Technical Reference Appendix E for information on indi‐
263 vidual patterns.
264 SPECIFYING COLOR
266 color The color of lines, areas and patterns can be specified by a
267 valid color name; by a gray shade (in the range 0-255); by a
268 decimal color code (r/g/b, each in range 0-255; h-s-v, ranges
269 0-360, 0-1, 0-1; or c/m/y/k, each in range 0-1); or by a hexa‐
270 decimal color code (#rrggbb, as used in HTML). See the gmtcol‐
271 ors manpage for more information and a full list of color names.
272
274 To make an overlay PostScript file that will mask out the regions of a
275 contour map where there is no control data using clip polygons, use:
276 psmask africa_grav.xyg -R20/40/20/40 -I5m -JM10i -O -K > mask.ps
278 The same example but this time we use white tiling:
280 psmask africa_grav.xyg -R20/40/20/40 -I5m -JM10i -T -O -K -Gwhite >
282 mask.ps
283
285 GMT(1), gmtcolors(5), grdmask(1), surface(1), psbasemap(1), psclip(1)
286GMT 4.5.6 10 Mar 2011 PSMASK(1)