.TH PSMASK l DATE
.SH NAME
psmask \- To clip or mask areas of no data on a map
.SH SYNOPSIS
\fBpsmask\fP [\fIxyzfile\fP] \fB\-I\fP\fIdx\fP[m|c][\fI/dy\fP[m|c]] \fB\-J\fP\fIparameters\fP 
\fB\-R\fP\fIwest/east/south/north\fP[\fIr\fP] [ \fB\-B\fP\fItickinfo\fP ] [ \fB\-C\fP\fIradius\fP[m|c] ] 
[ \fB\-D\fP\fIdumpfile\fP ] [ \fB\-E\fP\fIazimuth/elevation\fP ] [ \fB\-F\fP\fIred/green/blue\fP ] [ \fB\-G\fP\fIr/g/b\fP ] 
[ \fB\-H\fP ] [ \fB\-K\fP ] [ \fB\-N\fP ] [ \fB\-O\fP ] [ \fB\-P\fP ] [ \fB\-S\fP ] [ \fB\-T\fP ] 
[ \fB\-U\fP[\fI/dx/dy/\fP][\fIlabel\fP] ] [ \fB\-V\fP ] [ \fB\-X\fP\fIx-shift\fP ] [ \fB\-Y\fP\fIy-shift\fP ] 
[ \fB\-c\fP\fIcopies\fP ]  [ \fB\-:\fP ] [ \fB\-b\fP[\fBd\fP] ]
.SH DESCRIPTION
\fBpsmask\fP reads a (x,y,z) file [or standard input] and uses this information to find out
which grid cells are reliable.  Only gridcells which have one or more data points are considered
reliable.  As an option, you may specify a radius of influence. Then, all gridcells that are
within \fIradius\fP of a data point are considered reliable.  Furthermore, an option is provided to
reverse the sense of the test.  Having found the reliable/not reliable points, \fBpsmask\fP will
either paint tiles to mask these nodes (with the \fB\-T\fP) switch, or use contouring to create
polygons that will clip out regions of no interest.
.TP
\fIxyzfile\fP
File with (x,y,z) values (e.g., that was used to run \fBsurface\fP).  If no file
is given, standard input is read.  For binary files, see \fB\-b\fP.
.TP
.B \-I
\fIdx\fP [and optionally \fIdy\fP] are the size of the gridblocks. Append m to indicate minutes, or c to indicate seconds.
#include "explain_-j.txt"
#include "explain_-R.txt"
.SH OPTIONS
No space between the option flag and the associated arguments
.sp
#include "explain_-b.txt"
.TP
.B \-C
Sets radius of influence. Grid nodes within \fIradius\fP of a data point are considered reliable. [Default is 0, which
means that only grid cells with data in them are reliable].  Append m to indicate minutes, or c to indicate seconds.
.TP
.B \-D
Dumps out the resulting clipping polygons to disk.  Ignored if \fB\-T\fP is set.
.TP
.B \-E
Sets the viewpoint's azimuth and elevation for perspective plots [180/90]
.TP
.B \-F
Sets the color used for Frame and annotation. [Default is black]
.TP
.B \-G
Paint the clip polygons [or tiles] with the gray-shade (0-255) or color (r/g/b, each 0-255) [Default is no fill]
#include "explain_-H.txt"
Not used with binary data.
#include "explain_-K.txt"
.TP
.B \-N
Invert the sense of the test, i.e. clip regions where there is data coverage.
#include "explain_-O.txt"
#include "explain_-P.txt"
.TP
.B \-S
Mark end of existing clip path.  No input file is needed.  Implicitly sets \fB\-O\fP.
.TP
.B \-T
Plot tiles instead of clip polygons (Only works with \fB\-Jx\fP, \fB\-Jm\fP, \fB\-Jq\fP, and \fB\-Jy\fP).
#include "explain_-U.txt"
#include "explain_-V.txt"
#include "explain_-XY.txt"
#include "explain_-t.txt"
#include "explain_-c.txt"
.SH EXAMPLES
To make an overlay \fIPostScript\fP file that will mask out the regions of a contour map
where there is no control data using clip polygons, try:
.br
.sp
psmask africa_grav.xyg \fB\-R\fP20/40/20/40 \fB\-I\fP5m \fB\-J\fPM10 \fB\-O \-K\fP > mask.ps
.br
.sp
The same example but this time we use tiling:
.br
.sp
psmask africa_grav.xyg \fB\-R\fP20/40/20/40 \fB\-I\fP5m \fB\-J\fPM10 \fB\-T \-O \-K\fP > mask.ps
.SH SEE ALSO
gmt, surface, psbasemap, psclip
#include "refs.i"
