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 ins-
     tallation), 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  ano-
          tated.

     -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  MEASURE_UNIT  set-
          ting 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 origin)
          -Jmlon0/lat0/scale (Mercator - Give meridian and  stan-
          dard 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  ori-
          gin)
          -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[/origin] (polar (theta,r) coordinates, option-
          ally offset theta [0])
          -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  argu-
     ments.

     -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 out-
          line].

     -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 between each annotation along the  same
          contour [Default is 10c (or 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 tri-
          angle [Default computes these using Delaunay triangula-
          tion (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.
          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).   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  draw-
     ing  the  contours (pen = 2) given in the color palette file
     topo.cpt on a Lambert map at 0.5 inch/degree along the stan-
     dard 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  tempera-
     ture solution obtained on a triangular mesh whose node coor-
     dinates 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(l),   grdcontour(l),    grdimage(l),    nearneighbor(l),
     psbasemap(l), psscale(l), surface(l), triangulate(l)


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