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# psvelo

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

## Synopsis

psvelo [ table ] -Jparameters -R[unit]xmin/xmax/ymin/ymax[r] [ -Aparameters ] [ -B[p|s]parameters ] [ -Fcolor ] [ -Ecolor ] [ -Gfill ] [ -K ] [ -L ] [ -N ] [ -O ] [ -P ] [ -Ssymbol/scale/conf/font_size ] [ [ -U[just/dx/dy/][c|label] ] [ -V[level] ] [ -Wpen ] [ -X[a|c|f|r][x-shift[u]] ] [ -Y[a|c|f|r][y-shift[u]] ] [ -ccopies ] [ -h[i|o][n][+c][+d][+rremark][+rtitle] ] [ -icols[l][sscale][ooffset][,...] ] [ -:[i|o] ]

Note: No space is allowed between the option flag and the associated arguments.

## 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 It has been replaced by psvelo and psmeca.

## Required Arguments

table
  One or more ASCII (or binary, see -bi[ncols][type]) data table file(s) holding a number of data columns. If no tables are given then we read from standard input.

-Jparameters (more ...)
  Select map projection.

-Rwest/east/south/north[/zmin/zmax][r]
  west, east, south, and north specify the region of interest, and you may specify them in decimal degrees or in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left and upper right map coordinates are given instead of w/e/s/n. The two shorthands -Rg and -Rd stand for global domain (0/360 and -180/+180 in longitude respectively, with -90/+90 in latitude). Alternatively, specify the name of an existing grid file and the -R settings (and grid spacing, if applicable) are copied from the grid. Using -Runit expects projected (Cartesian) coordinates compatible with chosen -J and we inversely project to determine actual rectangular geographic region. For perspective view (-p), optionally append /zmin/zmax. In case of perspective view (-p), a z-range (zmin, zmax) can be appended to indicate the third dimension. This needs to be done only when using the -Jz option, not when using only the -p option. In the latter case a perspective view of the plane is plotted, with no third dimension.

-S

Selects 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).

-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

gives 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.

## Optional Arguments

-Aparameters
  Modify vector parameters. For vector heads, append vector head size [Default is 9p]. See VECTOR ATTRIBUTES for specifying additional attributes.

-B[p|s]parameters (more ...)
  Set map boundary intervals.
-DSigma_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 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
  Specify color (for symbols/polygons) or pattern (for polygons) [Default is black]. Optionally, specify -Gpicon_size/pattern, where pattern gives the number of the image pattern (1-90) 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.

-K (more ...)
  Do not finalize the PostScript plot.
-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 boundary specified by -R. [Default plots symbols inside frame only].

-O (more ...)
  Append to existing PostScript plot.

-P (more ...)
  Select “Portrait” plot orientation.

-U[just/dx/dy/][c|label] (more ...)
  Draw GMT time stamp logo on plot.

-V[level] (more ...)
  Select verbosity level [c].
-W
  Set pen attributes for velocity arrows, ellipse circumference and fault plane edges. [Defaults: width = default, color = black, style = solid].

-X[a|c|f|r][x-shift[u]]

-Y[a|c|f|r][y-shift[u]] (more ...)
  Shift plot origin.

-ccopies (more ...)
  Specify number of plot copies [Default is 1].

-h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
  Skip or produce header record(s).

-icols[l][sscale][ooffset][,...] (more ...)
  Select input columns.

-:[i|o] (more ...)
  Swap 1st and 2nd column on input and/or output.

-^
  Print a short message about the syntax of the command, then exits (NOTE: on Windows use just -).
+
  Print an extensive usage (help) message, including the explanation of any module-specific option (but not the GMT common options), then exits.
-?
  Print a complete usage (help) message, including the explanation of options, then exits.
--version
  Print GMT version and exit.
--show-datadir
  Print full path to GMT share directory and exit.

## Vector Attributes

Several modifiers may be appended to the vector-producing options to specify the placement of vector heads, their shapes, and the justification of the vector:

> +aangle sets the angle of the vector head apex [30].

> +b places a vector head at the beginning of the vector path [none].

> +e places a vector head at the end of the vector path [none].

> +g-|fill turns off vector head fill (if -) or sets the vector head fill [Default fill is used, which may be no fill].

> +l draws half-arrows, using only the left side [both].

> +nnorm scales down vector attributes (pen thickness, head size) with decreasing length, where vectors shorter than norm will have their attributes scaled by length/norm [arrow attributes remains invariant to length].

> +oplon/plat specifies the oblique pole for the great or small circles. Only needed for great circles if +q is given.

> +p[-][pen] sets the vector pen attributes. If pen has a leading - then the head outline is not drawn. [Default pen is used, and head outline is drawn]

> +q means the input angle, length is instead the start and stop opening angles of the arc segment relative to the point.

> +r draws half-arrows, using only the right side [both].

In addition, all but circular vectors may take these modifiers:

> +jjust determines how the input x,y point relates to the vector. Choose from beginning [default], end, or center.

> +s means the input angle, length is instead the x, y coordinates of the vector end point.

## 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.

>     gmt psvelo << END -h2 -R-10/10/-10/10 -W0.25p,red -Ggreen -L -Se0.2/0.39/18 \
>         -B1g1 -Jx0.4/0.4 -A0.3p -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

This 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.

>     gmt psvelo << END -Sw0.4/1.e7 -W0.75p -Gdarkgray -Elightgray -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

gmt, psbasemap, psxy

## References

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

## Authors

Kurt L. Feigl, Department of Geology and Geophysics at University of Wisconsin-Madison, Madison, Wisconsin, USA

Genevieve Patau, Laboratory of Seismogenesis, Institut de Physique du Globe de Paris, Departement de Sismologie, Paris, France

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