NAME
pscontour - Contour xyz-data by direct triangulation
SYNOPSIS
pscontour xyzfile -Ccptfile -Jparameters -Rwest/east/south/north[r] [
-A[ffont_size][aangle][/r/g/b][o]] ] [ -Btickinfo ] [ -D[dumpfile] ] [
-Eview_az/view_el ] [ -Ggap ] [ -H[nrec] ] [ -I ] [ -K ] [ -Lpen ] [
-M[flag] ] [ -N ] [ -O ] [ -P ] [ -Tindexfile ] [ -U[/dx/dy/][label] ]
[ -V ] [ -W[+]pen ] [ -Xx-shift ] [ -Yy-shift ] [ -ccopies ] [ -: ] [
-bi[s][n] ] [ -bo[s] ]
DESCRIPTION
pscontour reads an ASCII [or binary] xyz-file and produces a raw
contour plot by triangulation. By default, the optimal Delaunay
triangulation is performed (using either Shewhuck's [1996] or Watson's
[1982] method as selected during GMT installation), but the user may
optionally provide a second file with network information, such as a
triangular mesh used for finite element modeling. In addition to
contours, the area between contours may be painted according to the
color palette file.
xyzfile
Raw ASCII (or binary, see -b) xyz data to be contoured.
-C name of the color palette file. Must have discrete colors if you
want to paint the surface (-I). Only contours that have
anotation flags set will be anotated.
-J Selects the map projection. Scale is inch/degree, 1:xxxxx, or
width in inch (upper case modifier).
CYLINDRICAL PROJECTIONS:
-Jclon0/lat0/scale (Cassini)
-Jjlon0/scale (Miller)
-Jmscale (Mercator - Greenwich and Equator as origin)
-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/scale (TM - Transverse Mercator)
-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/scale (General Stereographic)
CONIC PROJECTIONS:
-Jblon0/lat0/lat1/lat2/scale (Albers)
-Jllon0/lat0/lat1/lat2/scale (Lambert)
MISCELLANEOUS PROJECTIONS:
-Jhlon0/scale (Hammer)
-Jilon0/scale (Sinusoidal)
-Jklon0/scale (Eckert VI)
-Jnlon0/scale (Robinson)
-Jrlon0/scale (Winkel Tripel)
-Jwlon0/scale (Mollweide)
NON-GEOGRAPHICAL PROJECTIONS:
-Jpscale (Linear projection for polar (theta,r) coordinates)
-Jxx-scale[l|ppow][/y-scale[l|ppow]] (Linear, log, and power
scaling)
More details can be found in the psbasemap manpages.
-R west, east, south, and north specify the Region of interest. To
specify boundaries in degrees and minutes [and seconds], use the
dd:mm[:ss] format. Append r if lower left and upper right map
coordinates are given instead of wesn.
OPTIONS
No space between the option flag and the associated arguments.
-A Several anotation formatting options can be set to modify the
form of the annotation. Append ffont_size to change font size
[9], append /r/g/b to change color of text fill box [PAGE_COLOR],
append aangle to fix annotation angle [Default follows contour],
and append o to draw the outline of the surrounding text box
[Default is no outline].
-B Sets map boundary tickmark intervals. See psbasemap for details.
-D Dump the (x,y,z) coordinates of each contour to separate files,
one for each contour segment. The files will be named
dumpfile_cont_segment[_i].xyz, where cont is the contour value
and segment is a running segment number for each contour interval
(for closed contours we append _i.) However, when -M is used in
conjunction with -D a single multisegment file is created
instead.
-E Sets the view point by specifying azimuth and elevation in
degrees. [Default is 180/90]
-G gap is distance in inch between each annotation along the same
contour [Default is 4i].
-H Input file(s) has Header record(s). Number of header records can
be changed by editing your .gmtdefaults file. If used, GMT
default is 1 header record.
-I Color the triangles using the color palette table.
-K More PostScript code will be appended later [Default terminates
the plot system].
-L Draw the underlying triangular mesh using the specified pen
attributes [Default is no mesh].
-M When used in conjunction with -D a single multisegment file is
created, and each contour section is preceeded by a header record
whose first column is flag followed by the contour level.
-N Do NOT clip contours or image at the boundaries [Defaults will
clip to fit inside region -R).
-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].
-T Give name of file with network information. Each record must
contain triplets of node numbers for a triangle [Default computes
these using Delaunay triangulation (see triangulate)].
-U Draw Unix System time stamp on plot. User may specify where the
lower left corner of the stamp should fall on the page relative
to lower left corner of plot in inch [Default is (-0.75i/-
0.75i)]. Optionally, append a label, or c (which will plot the
command string.)
-V Selects verbose mode, which will send progress reports to stderr
[Default runs "silently"].
-W Select contouring and set contour pen attributes. If the + flag
is set then the contour lines are colored according to the cpt
file (see -C).
-X -Y
Shift origin of plot by (x-shift,y-shift) inch [Default is
(a1i,a1i) for new plots, (0,0) for overlays]. Prepend a for
absolute coordinates; the default (r) will reset plot origin.
-c Specifies the number of plot copies. [Default is 1]
-: Toggles between (longitude,latitude) and (latitude,longitude)
input/output. [Default is (longitude,latitude)].
-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 3 input columns]. Use 4-byte integer
triplets for node ids (-T).
-bo Selects binary output. Append s for single precision [Default is
double].
EXAMPLES
To make a raw contour plot from the file topo.xyz and drawing the
contours (pen = 2) given in the color palette file topo.cpt on a
Lambert map at 0.5 inch/degree along the standard parallels 18 and 24,
try
pscontour topo.xyz -R320/330/20/30 -Jl18/24/0.5i -Ctopo.cpt -W0.5p >
topo.ps
To create a color PostScript plot of the numerical temperature
solution obtained on a triangular mesh whose node coordinates and
temperatures are stored in temp.xyz and mesh arrangement is given by
the file mesh.ijk, using the colors in temp.cpt, try
pscontour temp.xyz -R0/150/0/100 -Jx0.1 -Ctemp.cpt -G -W0.25p >
temp.ps
BUGS
Sometimes there will appear to be thin lines of the wrong color in the
image. This is a round-off problem which may be remedied by using a
higher value of DOTS_PR_INCH in the .gmtdefaults file.
SEE ALSO
gmt, grdcontour, grdimage, nearneighbor, psbasemap, psscale, surface,
triangulate
REFERENCES
Watson, D. F., 1982, Acord: Automatic contouring of raw data, Comp. &
Geosci., 8, 97-101.
Shewchuck, J. R., 1996, Triangle: Engineering a 2D Quality Mesh
Generator and Delaunay Triangulator, First Workshop on Applied
Computational Geometry (Philadelphia, PA), 124-133, ACM, May 1996.
www.cs.cmu.edu/~quake/triangle.html
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