psclip
psclip - To set up polygonal clip paths
SYNOPSIS
psclip xyfiles -Jparameters -Rwest/east/south/north[r] [
-Btickinfo ] [ -Eaz/el ] [ -K ] [ -N ] [ -M[flag] ] [ -O ]
[ -P ] [ -U[/dx/dy/][label] ] [ -V ] [ -Xx-shift ] [ -Yy-
shift ] [ -Zzlevel ] [ -ccopies ] [ -: ] [ -bi[s][n] ]
psclip -C [ -K ] [ -O ]
DESCRIPTION
psclip reads (x,y) file(s) [or standard input] and draws
polygons that are activated as clipping paths. Several
files may be read to create complex paths consisting of
several non-connecting segments. As an option (-N), the
user may choose to reverse the sense of what is the inside
and outside of the paths. After subsequent plotting,
which will be clipped against these paths, the clipping
may be deactivated by running psclip a second time with
the -C option only.
xyfiles
ASCII [or binary, see -b] file(s) with (x,y) values
for clip polygons. If no files are given, the stan
dard input is read.
-C Mark end of existing clip path. No input file or
projection information are needed.
-J Selects the map projection. Scale is UNIT/degree,
1:xxxxx, or width in UNIT (upper case modifier).
UNIT is cm, inch, or m, depending on the MEA
SURE_UNIT setting in .gmtdefaults, but this can be
overridden on the command line by appending the c,
i, or m to the scale/width value.
CYLINDRICAL PROJECTIONS:
-Jclon0/lat0/scale (Cassini)
-Jjlon0/scale (Miller)
-Jmscale (Mercator - Greenwich and Equator as ori
gin)
-Jmlon0/lat0/scale (Mercator - Give meridian and
standard parallel)
-Joalon0/lat0/azimuth/scale (Oblique Mercator -
point and azimuth)
-Joblon0/lat0/lon1/lat1/scale (Oblique Mercator -
two points)
-Joclon0/lat0/lonp/latp/scale (Oblique Mercator -
point and pole)
-Jqlon0/scale (Equidistant Cylindrical Projection
(Plate Carree))
-Jtlon0/lat0/scale (TM - Transverse Mercator, set
origin)
-Juzone/scale (UTM - Universal Transverse Mercator)
-Jylon0/lats/scale (Basic Cylindrical Projection)
AZIMUTHAL PROJECTIONS:
-Jalon0/lat0/scale (Lambert).
-Jelon0/lat0/scale (Equidistant).
-Jflon0/lat0/horizon/scale (Gnomonic).
-Jglon0/lat0/scale (Orthographic).
-Jslon0/lat0/[slat/]scale (General Stereographic)
CONIC PROJECTIONS:
-Jblon0/lat0/lat1/lat2/scale (Albers)
-Jdlon0/lat0/lat1/lat2/scale (Equidistant)
-Jllon0/lat0/lat1/lat2/scale (Lambert)
MISCELLANEOUS PROJECTIONS:
-Jhlon0/scale (Hammer)
-Jilon0/scale (Sinusoidal)
-Jk[f|s]lon0/scale (Eckert IV (f) and VI (s))
-Jnlon0/scale (Robinson)
-Jrlon0/scale (Winkel Tripel)
-Jvlon0/scale (Van der Grinten)
-Jwlon0/scale (Mollweide)
NON-GEOGRAPHICAL PROJECTIONS:
-Jp[a]scale[/origin] (polar (theta,r) coordinates,
optional a for azimuths and offset theta [0])
-Jxx-scale[l|ppow][/y-scale[l|ppow]] (Linear, log,
and power scaling)
More details can be found in the psbasemap man
pages.
-R west, east, south, and north specify the Region of
interest. To specify boundaries in degrees and min
utes [and seconds], use the dd:mm[:ss] format.
Append r if lower left and upper right map coordi
nates are given instead of wesn.
OPTIONS
No space between the option flag and the associated argu
ments
-B Sets map boundary tickmark intervals. See psbasemap
for details.
-H Input file(s) has Header record(s). Number of
header records can be changed by editing your .gmt
defaults file. If used, GMT default is 1 header
record.
-K More PostScript code will be appended later
[Default terminates the plot system].
-M Multiple segment file. Segments are separated by a
record whose first character is <flag>. [Default
is '>'].
-N Invert the sense of what is inside and outside,
i.e., use the outside of the polygons for clipping.
-O Selects Overlay plot mode [Default initializes a
new plot system].
-P Selects Portrait plotting mode [GMT Default is
Landscape, see gmtdefaults to change this].
-U Draw Unix System time stamp on plot. User may spec
ify where the lower left corner of the stamp should
fall on the page relative to lower left corner of
plot. Optionally, append a label, or c (which will
plot the command string.). The GMT parameters
UNIX_TIME and UNIX_TIME_POS can affect the appear
ance; see the gmtdefaults man page for details.
-V Selects verbose mode, which will send progress
reports to stderr [Default runs "silently"].
-X -Y Shift origin of plot by (x-shift,y-shift). Prepend
a for absolute coordinates; the default (r) will
reset plot origin.
-Z For 3-D projections: Sets the z-level of the poly
gons [0].
-: Toggles between (longitude,latitude) and (lati
tude,longitude) input/output. [Default is (longi
tude,latitude)]. Applies to geographic coordinates
only.
-c Specifies the number of plot copies. [Default is 1]
-bi Selects binary input. Append s for single precision
[Default is double]. Append n for the number of
columns in the binary file(s). [Default is 2 input
columns].
To make an overlay PostScript file that will set up a com
plex clip area to which subsequent plotting will be con
fined to, try:
psclip my_region.xy -R0/40/0/40 -Jm0.3i -O -K >
clip_mask_on.ps
To deactivate the clipping in an existing plotfile, run:
psclip -C -O >> complex_plot.ps
BUGS
psclip cannot handle polygons that contain the south or
north pole. For such polygons, you should split them into
two and make each explicitly contain the polar point. The
two clip polygons will combine to give the desired effect.
SEE ALSO
gmt(l), grdmask(l), psbasemap(l), psmask(l)
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