## 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 cm/degree, 1:xxxxx, or width
               in cm (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, with Equator as y = 0)
               -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/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:

               -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.  Give - to disable all anotations.
               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 cm between each annotation along the same
               contour [Default is 10c].

          -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 cm [Default is (-2c/-2c)].
               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) cm  [Default is
               (a2.5c,a2.5c) 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 1.3 cm/degree along the standard parallels 18 and 24,
          try

          pscontour topo.xyz -R320/330/20/30 -Jl18/24/1.3c -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