NAME

       pscontour - Contour xyz-data by direct triangulation


SYNOPSIS

       pscontour       xyzfile       -Ccptfile       -Jparameters
       -Rwest/east/south/north[r]    [     -A[-][ffont_size][aan­
       gle][/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][n]
       ]


DESCRIPTION

       pscontour reads an ASCII [or binary] xyz-file and produces
       a raw contour plot by triangulation. By default, the opti­
       mal Delaunay triangulation is performed (using either She­
       whuck's [1996]' or Watson's [1982] method as selected dur­
       ing GMT installation), but the user' may  optionally  pro­
       vide  a  second  file  with network information, such as a
       triangular mesh used for finite element modeling. In addi­
       tion 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  con­
              toured.

       -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  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/scale (TM - Transverse Mercator, with Equa­
              tor 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/[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.

       -A     Several anotation formatting options can be set  to
              modify  the  form of the annotation. Give - to dis­
              able 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  multi­
              segment 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 .gmt­
              defaults  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 spec­
              ified pen attributes [Default is no mesh].

       -M     When used in conjunction with -D a single multiseg­
              ment 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 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"].

       -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  (lati­
              tude,longitude)  input/output.  [Default is (longi­
              tude,latitude)].  Applies to geographic coordinates
              only.

       -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 preci­
              sion [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 temper­
       ature  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(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



                            1 Mar 2002               PSCONTOUR(l)

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