1PSCLIP(1) Generic Mapping Tools PSCLIP(1)
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6 psclip - To set up polygonal clip paths
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9 psclip xyfiles -Jparameters -Rwest/east/south/north[r] [ -B[p|s]parame‐
10 ters ] [ -Eazim/elev ] [ -K ] [ -N ] [ -O ] [ -P ] [ -T ] [
11 -U[just/dx/dy/][c|label] ] [ -V ] [ -X[a|c|r][x-shift[u]] ] [
12 -Y[a|c|r][y-shift[u]] ] [ -Zzlevel ] [ -ccopies] [ -:[i|o] ] [
13 -bi[s|S|d|D[ncol]|c[var1/...]] ] [ -fcolinfo ] [ -m[flag] ]
14 psclip -C [ -K ] [ -O ]
16
18 psclip reads (x,y) file(s) [or standard input] and draws polygons that
19 are activated as clipping paths. Several files may be read to create
20 complex paths consisting of several non-connecting segments. Only
21 marks that are subsequently drawn inside the clipping path will be
22 shown. To determine what is inside or outside the clipping path, psclip
23 uses the even-odd rule. When a ray drawn from any point, regardless of
24 direction, crosses the clipping path segments an odd number of times,
25 the point is inside the clipping path. If the number is even, the
26 point is outside. The -N option, reverses the sense of what is the
27 inside and outside of the paths by plotting a clipping path along the
28 map boundary. After subsequent plotting, which will be clipped against
29 these paths, the clipping may be deactivated by running psclip a second
30 time with the -C option only.
31 xyfiles
33 ASCII [or binary, see -b] file(s) with (x,y) values for clip
34 polygons. If no files are given, the standard input is read.
35 -C Mark end of existing clip path. No input file or projection
37 information are needed. However, you must supply -Xa and -Ya
38 settings if you are using absolute positioning.
39 -J Selects the map projection. Scale is UNIT/degree, 1:xxxxx, or
41 width in UNIT (upper case modifier). UNIT is cm, inch, or m,
42 depending on the MEASURE_UNIT setting in .gmtdefaults4, but this
43 can be overridden on the command line by appending c, i, or m to
44 the scale/width value. When central meridian is optional,
45 default is center of longitude range on -R option. Default
46 standard parallel is the equator. For map height, max dimen‐
47 sion, or min dimension, append h, +, or - to the width, respec‐
48 tively.
49 More details can be found in the psbasemap man pages.
50 CYLINDRICAL PROJECTIONS:
52 -Jclon0/lat0/scale (Cassini)
54 -Jcyl_stere/[lon0/[lat0/]]scale (Cylindrical Stereographic)
55 -Jj[lon0/]scale (Miller)
56 -Jm[lon0/[lat0/]]scale (Mercator)
57 -Jmlon0/lat0/scale (Mercator - Give meridian and standard paral‐
58 lel)
59 -Jo[a]lon0/lat0/azimuth/scale (Oblique Mercator - point and
60 azimuth)
61 -Jo[b]lon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
62 -Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and
63 pole)
64 -Jq[lon0/[lat0/]]scale (Cylindrical Equidistant)
65 -Jtlon0/[lat0/]scale (TM - Transverse Mercator)
66 -Juzone/scale (UTM - Universal Transverse Mercator)
67 -Jy[lon0/[lat0/]]scale (Cylindrical Equal-Area)
68 CONIC PROJECTIONS:
70 -Jblon0/lat0/lat1/lat2/scale (Albers)
72 -Jdlon0/lat0/lat1/lat2/scale (Conic Equidistant)
73 -Jllon0/lat0/lat1/lat2/scale (Lambert Conic Conformal)
74 -Jpoly/[lon0/[lat0/]]scale ((American) Polyconic)
75 AZIMUTHAL PROJECTIONS:
77 -Jalon0/lat0[/horizon]/scale (Lambert Azimuthal Equal-Area)
79 -Jelon0/lat0[/horizon]/scale (Azimuthal Equidistant)
80 -Jflon0/lat0[/horizon]/scale (Gnomonic)
81 -Jglon0/lat0[/horizon]/scale (Orthographic)
82 -Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale
83 (General Perspective).
84 -Jslon0/lat0[/horizon]/scale (General Stereographic)
85 MISCELLANEOUS PROJECTIONS:
87 -Jh[lon0/]scale (Hammer)
89 -Ji[lon0/]scale (Sinusoidal)
90 -Jkf[lon0/]scale (Eckert IV)
91 -Jk[s][lon0/]scale (Eckert VI)
92 -Jn[lon0/]scale (Robinson)
93 -Jr[lon0/]scale (Winkel Tripel)
94 -Jv[lon0/]scale (Van der Grinten)
95 -Jw[lon0/]scale (Mollweide)
96 NON-GEOGRAPHICAL PROJECTIONS:
98 -Jp[a]scale[/origin][r|z] (Polar coordinates (theta,r))
100 -Jxx-scale[d|l|ppow|t|T][/y-scale[d|l|ppow|t|T]] (Linear, log,
101 and power scaling)
102 -R xmin, xmax, ymin, and ymax specify the Region of interest. For
104 geographic regions, these limits correspond to west, east,
105 south, and north and you may specify them in decimal degrees or
106 in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left
107 and upper right map coordinates are given instead of w/e/s/n.
108 The two shorthands -Rg and -Rd stand for global domain (0/360
109 and -180/+180 in longitude respectively, with -90/+90 in lati‐
110 tude). Alternatively, specify the name of an existing grid file
111 and the -R settings (and grid spacing, if applicable) are copied
112 from the grid. For calendar time coordinates you may either
113 give (a) relative time (relative to the selected TIME_EPOCH and
114 in the selected TIME_UNIT; append t to -JX|x), or (b) absolute
115 time of the form [date]T[clock] (append T to -JX|x). At least
116 one of date and clock must be present; the T is always required.
117 The date string must be of the form [-]yyyy[-mm[-dd]] (Gregorian
118 calendar) or yyyy[-Www[-d]] (ISO week calendar), while the clock
119 string must be of the form hh:mm:ss[.xxx]. The use of delim‐
120 iters and their type and positions must be exactly as indicated
121 (however, input, output and plot formats are customizable; see
122 gmtdefaults).
123
125 No space between the option flag and the associated arguments.
126 -B Sets map boundary annotation and tickmark intervals; see the
129 psbasemap man page for all the details.
130 -E Sets the viewpoint's azimuth and elevation [180/90].
132 -H Input file(s) has header record(s). If used, the default number
134 of header records is N_HEADER_RECS. Use -Hi if only input data
135 should have header records [Default will write out header
136 records if the input data have them]. Blank lines and lines
137 starting with # are always skipped.
138 -K More PostScript code will be appended later [Default terminates
140 the plot system].
141 -N Invert the sense of what is inside and outside. For example,
143 when using a single path, this means that only points outside
144 that path will be shown. Cannot be used together with -B.
145 -O Selects Overlay plot mode [Default initializes a new plot sys‐
147 tem].
148 -P Selects Portrait plotting mode [Default is Landscape, see gmtde‐
150 faults to change this].
151 -T Rather than read any input files, simply turn on clipping for
153 the current map region. Basically, -T is a convenient way to
154 run psclip with the arguments -N /dev/null (or, under Windows,
155 -N NUL). Cannot be used together with -B.
156 -U Draw Unix System time stamp on plot. By adding just/dx/dy/, the
158 user may specify the justification of the stamp and where the
159 stamp should fall on the page relative to lower left corner of
160 the plot. For example, BL/0/0 will align the lower left corner
161 of the time stamp with the lower left corner of the plot.
162 Optionally, append a label, or c (which will plot the command
163 string.). The GMT parameters UNIX_TIME, UNIX_TIME_POS, and
164 UNIX_TIME_FORMAT can affect the appearance; see the gmtdefaults
165 man page for details. The time string will be in the locale set
166 by the environment variable TZ (generally local time).
167 -V Selects verbose mode, which will send progress reports to stderr
169 [Default runs "silently"].
170 -X -Y Shift plot origin relative to the current origin by (x-shift,y-
172 shift) and optionally append the length unit (c, i, m, p). You
173 can prepend a to shift the origin back to the original position
174 after plotting, or prepend r [Default] to reset the current
175 origin to the new location. If -O is used then the default (x-
176 shift,y-shift) is (0,0), otherwise it is (r1i, r1i) or (r2.5c,
177 r2.5c). Alternatively, give c to align the center coordinate (x
178 or y) of the plot with the center of the page based on current
179 page size.
180 -Z For 3-D projections: Sets the z-level of the polygons [0].
182 -: Toggles between (longitude,latitude) and (latitude,longitude)
184 input and/or output. [Default is (longitude,latitude)]. Append
185 i to select input only or o to select output only. [Default
186 affects both].
187 -bi Selects binary input. Append s for single precision [Default is
189 d (double)]. Uppercase S or D will force byte-swapping.
190 Optionally, append ncol, the number of columns in your binary
191 input file if it exceeds the columns needed by the program. Or
192 append c if the input file is netCDF. Optionally, append
193 var1/var2/... to specify the variables to be read. [Default is
194 2 input columns].
195 -c Specifies the number of plot copies. [Default is 1].
197 -f Special formatting of input and/or output columns (time or geo‐
199 graphical data). Specify i or o to make this apply only to
200 input or output [Default applies to both]. Give one or more
201 columns (or column ranges) separated by commas. Append T (abso‐
202 lute calendar time), t (relative time in chosen TIME_UNIT since
203 TIME_EPOCH), x (longitude), y (latitude), or f (floating point)
204 to each column or column range item. Shorthand -f[i|o]g means
205 -f[i|o]0x,1y (geographic coordinates).
206 -m Multiple segment file(s). Segments are separated by a special
208 record. For ASCII files the first character must be flag
209 [Default is '>']. For binary files all fields must be NaN and
210 -b must set the number of output columns explicitly. By default
211 the -m setting applies to both input and output. Use -mi and
212 -mo to give separate settings to input and output.
213
215 To make an overlay PostScript file that will set up a complex clip area
216 to which subsequent plotting will be confined, run:
217 psclip my_region.xy -R0/40/0/40 -Jm0.3i -O -K > clip_mask_on.ps
219 To deactivate the clipping in an existing plotfile, run:
221 psclip -C -O >> complex_plot.ps
223
225 psclip cannot handle polygons that contain the south or north pole.
226 For such polygons, you should split them into two and make each explic‐
227 itly contain the polar point. The two clip polygons will combine to
228 give the desired effect.
229
231 GMT(1), grdmask(1), psbasemap(1), psmask(1)
232GMT 4.5.6 10 Mar 2011 PSCLIP(1)