## NAME

          psvelo - Plot velocity vectors, crosses, and wedges on maps

## SYNOPSIS

          psvelo files -Jparameters -Rwest/east/south/north [ -Btickinfo ] [
          -Dsigma_scale ] [ -Fred/green/blue ] [ -Ered/green/blue ] [ -Gfill ] [
          -H ] [ -K ] [ -L ] [ -N ] [ -O ] [ -P ] [ -Ssymbol/scale/conf/font_size
          ] [ -U[/dx/dy/][label] ] [ -V ] [ -Wpen ] [ -Xx-shift ] [ -Yy-shift ] [
          -: ] [ -ccopies ]

## DESCRIPTION

          psvelo reads data values from files [or standard input] and generates
          PostScript code that will plot velocity arrows on a map.  Most options
          are the same as for psxy, except -S The PostScript code is written to
          standard output. The previous version (psvelomeca) is now obsolete. It
          has been replaced by psvelo and psmeca.

## ARGUMENTS

          files List one or more file-names. If no files are given, psvelo will
          read standard input.

          -J   Selects the map projection. Scale is UNIT/degree, 1:xxxxx. or
               width in UNIT (upper case modifier).

               See psbasemap man pages for details.

               -R west, east, south, and north specify the Region of interest.
               To specify your boundaries in degrees and minutes [and seconds],
               use the dd:mm[:ss] format.

               -SSelects the meaning of the columns in the data file and the
               figure to be plotted.

               -Sevelscale/confidence/fontsize.  Velocity ellipses in (N,E)
               convention.  Vscale sets the scaling of the velocity arrows.
               This scaling gives inches (unless c, i, m, or p is appended).
                 Confidence sets the 2-dimensional confidence limit for the
               ellipse, e.g., 0.95 for 95% confidence ellipse.  Fontsize sets
               the size of the text in points.  The ellipse will be filled with
               the color or shade specified by the -G option [default
               transparent].  The arrow and the circumference of the ellipse
               will be drawn with the pen attributes specified by the -W option.
               Parameters are expected to be in the following columns:

          1,2  longitude, latitude of station (-: option interchanges order)

          3,4  eastward, northward velocity (-: option interchanges order)

          5,6  uncertainty of eastward, northward velocities (1-sigma) (-:
               option interchanges order)

          7    correlation between eastward and northward components

          8    name of station (optional). The bug which previously wrote a
               garbage string if this argument was omitted has been fixed.

               -Snbarscale.  Anisotropy bars.  Barscale sets the scaling of the
               bars This scaling gives inches (unless c, i, m, or p is
               appended).  Parameters are expected to be in the following
               columns:

          1,2  longitude, latitude of station (-: option interchanges order)

          3,4  eastward, northward components of anisotropy vector (-: option
               interchanges order)

               -Srvelscale/confidence/fontsize.  Velocity ellipses in rotated
               convention.  Vscale sets the scaling of the velocity arrows. This
               scaling gives inches (unless c, i, m, or p is appended).
                Confidence sets the 2-dimensional confidence limit for the
               ellipse, e.g., 0.95 for 95% confidence ellipse.  Fontsize sets
               the size of the text in points.  The ellipse will be filled with
               the color or shade specified by the -G option [default
               transparent].  The arrow and the circumference of the ellipse
               will be drawn with the pen attributes specified by the -W option.
               Parameters are expected to be in the following columns:

          1,2  longitude, latitude, of station (-: option interchanges order)

          3,4  eastward, northward velocity (-: option interchanges order)

          5,6  semi-major, semi-minor axes

          7    counter-clockwise angle, in degrees, from horizontal axis to
               major axis of ellipse.

          8    name of station (optional)

               -Swwedge_scale/wedge_mag. Rotational wedges.  Wedge_scale sets
               the size of the wedges in inches (unless c, i, m, or p is
               appended).  Values are multiplied by Wedge_mag before plotting.
               For example, setting Wedge_mag to 1.e7 works well for rotations
               of the order of 100 nanoradians/yr.  Use -G to set the fill color
               or shade for the wedge, and -E to set the color or shade for the
               uncertainty.  Parameters are expected to be in the following
               columns:

          1,2  longitude, latitude, of station (-: option interchanges order)

          3    rotation in radians

          4    rotation uncertainty in radians

               -Sxcross_scale  Strain crosses.  Cross_scale sets the size of the
               cross in inches (unless c, i, m, or p is appended).  Parameters
               are expected to be in the following columns:

          1,2  longitude, latitude, of station (-: option interchanges order)

          3    eps1, the most extensional eigenvalue of strain tensor, with
               extension taken positive.

          4    eps2, the most compressional eigenvalue of strain tensor, with
               extension taken positive.

          5    azimuth of eps2 in degrees CW from North.

               -R west, east, south, and north specify the region of interest.
                 To specify your boundaries in degrees and minutes, use the
               dd:mm format by appending 'm'.

## OPTIONS

          No space between the option flag and the associated arguments.

          -A Arrow_width/Head_length/Head_width Size of arrow in inches.
          [Default is 0.03/0.12/0.09].

          -B Sets map boundary tickmark intervals. See psbasemap for details.

          -C Offset focal mechanisms to the latitude and longitude specified in
          the last two columns of the input file.

          -D Sigma_scale can be used to rescale the uncertainties of velocities
          (-Se and -Sr) and rotations (-Sw).  Can be combined with the
          confidence  variable.

          -Ffill Sets the color or shade used for frame and annotation. [Default
          is 0/0/0 (black)]

          -Efill Sets the color or shade used for filling uncertainty wedges (-
          Sw) or velocity error ellipses (-Se or -Sr).  [If -E is not specified,
          the uncertainty regions will be transparent.]

          -Gfill Select filling of ellipses, wedges, and focal mechanisms.  By
          convention, the compressional quadrants of the focal mechanism beach
          balls are shaded.  Set the shade (0-255) or color (r/g/b) [Default is
          0/0/0].  Optionally, specify -Gpicon_size/pattern, where pattern gives
          the number of the image pattern (1-32) OR the name of a icon-format
          file.  icon_size sets the unit size in inches.  To invert black and
          white pixels, use -GP instead of -Gp.  See pspatterns for information
          on individual patterns.

          -H Input file(s) has Header record(s).

          -K Means more PostScript code will be appended later. [Default
          terminates the plot system]

          -L Draw lines.  Ellipses and fault planes will have their outlines
          drawn using current pen (see -W).

          -N Do NOT skip symbols that fall outside the frame boudary specified
          by -R.
           [Default plots symbols inside frame only].

          -O Selects Overlay plot mode. [Default initializes a new plot system]

          -P Selects Portrait plotting mode. [Default is Landscape]

          -U Draw Unix System time stamp on plot.  Append c to plot the command
          line or a text string of your choice.

          -V Verbose.  Reports the name of the current file being plotted, as
          well as number of records, and any scaling information.

          -W Set pen attributes for velocity arrows, ellipse circumference and
          fault plane edges.
           [Defaults: width = 1, color = 0/0/0, texture = solid].

          -X -Y Shift origin of plot by (x-shift,y-shift) inches  [Default is
          (1,1) for new plots, (0,0) for overlays].

          -: Toggles between (longitude,latitude) and (latitude,longitude)
          input/output.  [Default is (longitude,latitude)]

          -c Specifies the number of plot copies. [Default is 1]

## EXAMPLES

          The following should make big red arrows with green ellipses, outlined
          in red.  Note that the 39% confidence scaling will give an ellipse
          which fits inside a rectangle of dimension Esig by Nsig.

          psvelo << END -H2 -R-10/10/-10/10 -W1/255/0/0 \
          -G0/255/0 -L -Se0.2/0.39/18 -B1g1 -Jx0.4/0.4 \
          -A0.1/0.3/0.3 -P -V  >! test.ps
            Long.   Lat.   Evel   Nvel   Esig   Nsig  CorEN SITE
            (deg)  (deg)    (mm/yr)        (mm/yr)
             0.    -8.     0.0    0.0     4.0    6.0  0.500  4x6
            -8.     5.     3.0    3.0     0.0    0.0  0.500  3x3
             0.     0.     4.0    6.0     4.0    6.0  0.500
            -5.    -5.     6.0    4.0     6.0    4.0  0.500  6x4
             5.     0.    -6.0    4.0     6.0    4.0 -0.500  -6x4
             0.    -5.     6.0   -4.0     6.0    4.0 -0.500  6x-4
          END
          The example should plot some residual rates of rotation in the Western
          Transverse Ranges, California.  The wedges will be dark gray, with
          light gray wedges to represent the 2-sigma uncertainties.

          psvelo <<END -Sw0.4/1.e7 -W3 -G60 -E210 -H1 -D2 -Jm2.2 \
          -R240./243./32.5/34.75 -Bf10ma60m/WeSn -P >! test.ps
           lon     lat    spin(rad/yr) spin_sigma (rad/yr)
          241.4806 34.2073  5.65E-08 1.17E-08
          241.6024 34.4468 -4.85E-08 1.85E-08
          241.0952 34.4079  4.46E-09 3.07E-08
          241.2542 34.2581  1.28E-07 1.59E-08
          242.0593 34.0773 -6.62E-08 1.74E-08
          241.0553 34.5369 -2.38E-07 4.27E-08
          241.1993 33.1894 -2.99E-10 7.64E-09
          241.1084 34.2565  2.17E-08 3.53E-08
          END

## SEE ALSO

          gmtsystem, psbasemap, psxy.

## REFERENCES

          Bomford, G., Geodesy, 4th ed., Oxford University Press, 1980.

## AUTHORS

          Kurt Feigl
          CNRS UMR 5562
          Toulouse, France
          (Kurt.Feigl@.cnes.fr)
          Genevieve Patau
          CNRS UMR 7580
          Seismology Dept.
          Institut de Physique du Globe de Paris
          (patau@ipgp.jussieu.fr)