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