# PSVELO

NAME
SYNOPSIS
DESCRIPTION
ARGUMENTS
OPTIONS
EXAMPLES
SEE ALSO
REFERENCES
AUTHORS

## NAME

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

## SYNOPSIS

psvelo files −J parameters −R west/east/south/north[r] [ −A Arrow_width/Head_length/Head_width ] [ −B[p|s]parameters ] [ −D sigma_scale ] [ −F color ] [ −E color ] [ −G fill ] [ −H[i][nrec] ] [ −K ] [ −L ] [ −N ] [ −O ] [ −P ] [ −S symbol/scale/conf/font_size ] [ −U[just/dx/dy/][c|label] ] [ −V ] [ −W pen ] [ −X[a|c|r][x-shift[u]] ] [ −Y[a|c|r][y-shift[u]] ] [ −:[i|o] ] [ −c copies ]

## 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 It has been replaced by psvelo and psmeca.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). UNIT is cm, inch, or m, depending on the MEASURE_UNIT setting in .gmtdefaults4, but this can be overridden on the command line by appending c, i, or m to the scale/width value. When central meridian is optional, default is center of longitude range on −R option. Default standard parallel is the equator. For map height, max dimension, or min dimension, append h, +, or - to the width, respectively.

More details can be found in the psbasemap man pages.

CYLINDRICAL PROJECTIONS:

−Jc lon0/lat0/scale (Cassini)
−Jcyl_stere/[lon0/[lat0/]]scale (Cylindrical Stereographic)
−Jj[lon0/]scale (Miller)
−Jm[lon0/[lat0/]]scale (Mercator)
−Jm lon0/lat0/scale (Mercator - Give meridian and standard parallel)
−Jo[a]lon0/lat0/azimuth/scale (Oblique Mercator - point and azimuth)
−Jo[b]lon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
−Joc lon0/lat0/lonp/latp/scale (Oblique Mercator - point and pole)
−Jq[lon0/[lat0/]]scale (Cylindrical Equidistant)
−Jt lon0/[lat0/]scale (TM - Transverse Mercator)
−Ju zone/scale (UTM - Universal Transverse Mercator)
−Jy[lon0/[lat0/]]scale (Cylindrical Equal-Area)

CONIC PROJECTIONS:

−Jb lon0/lat0/lat1/lat2/scale (Albers)
−Jd lon0/lat0/lat1/lat2/scale (Conic Equidistant)
−Jl lon0/lat0/lat1/lat2/scale (Lambert Conic Conformal)
−Jpoly/[lon0/[lat0/]]scale ((American) Polyconic)

AZIMUTHAL PROJECTIONS:

−Ja lon0/lat0[/horizon]/scale (Lambert Azimuthal Equal-Area)
−Je lon0/lat0[/horizon]/scale (Azimuthal Equidistant)
−Jf lon0/lat0[/horizon]/scale (Gnomonic)
−Jg lon0/lat0[/horizon]/scale (Orthographic)
−Jg lon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale (General Perspective).
−Js lon0/lat0[/horizon]/scale (General Stereographic)

MISCELLANEOUS PROJECTIONS:

−Jh[lon0/]scale (Hammer)
−Ji[lon0/]scale (Sinusoidal)
−Jkf[lon0/]scale (Eckert IV)
−Jk[s][lon0/]scale (Eckert VI)
−Jn[lon0/]scale (Robinson)
−Jr[lon0/]scale (Winkel Tripel)
−Jv[lon0/]scale (Van der Grinten)
−Jw[lon0/]scale (Mollweide)

NON-GEOGRAPHICAL PROJECTIONS:

−Jp[a]scale[/origin][r|z] (Polar coordinates (theta,r))
−Jx x-scale[d|l|p pow|t|T][/y-scale[d|l|p pow|t|T]] (Linear, log, and power scaling)

| −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.

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

−Se velscale/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).

−Sn barscale.

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)

−Sr velscale/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)

−Sw wedge_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

−Sx cross_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.

## 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 annotation and tickmark intervals; see the psbasemap man page for all the details.
| −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.
| −F fill |  | Sets the color or shade used for frame and annotation. [Default is 0/0/0 (black)]
| −E fill |  | 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.]
| −G fill |  | Specify color (for symbols/polygons) or pattern (for polygons). Set the shade (0−255) or color (r/g/b) [Default is 0/0/0]. Optionally, specify −Gp icon_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.
| −H |  | Input file(s) has header record(s). If used, the default number of header records is N_HEADER_RECS. Use −Hi if only input data should have header records [Default will write out header records if the input data have them]. Blank lines and lines starting with # are always skipped.
| −K |  | 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 boundary 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, see gmtdefaults to change this].
| −U |  | Draw Unix System time stamp on plot. By adding just/dx/dy/, the user may specify the justification of the stamp and where the stamp should fall on the page relative to lower left corner of the plot. For example, BL/0/0 will align the lower left corner of the time stamp with the lower left corner of the plot. Optionally, append a label, or c (which will plot the command string.). The GMT parameters UNIX_TIME, UNIX_TIME_POS, and UNIX_TIME_FORMAT can affect the appearance; see the gmtdefaults man page for details. The time string will be in the locale set by the environment variable TZ (generally local time).
| −V |  | Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
| −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 plot origin relative to the current origin by (x-shift,y-shift) and optionally append the length unit (c, i, m, p). You can prepend a to shift the origin back to the original position after plotting, or prepend r [Default] to reset the current origin to the new location. If −O is used then the default (x-shift,y-shift) is (0,0), otherwise it is (r1i, r1i) or (r2.5c, r2.5c). Alternatively, give c to align the center coordinate (x or y) of the plot with the center of the page based on current page size.
| −: |  | Toggles between (longitude,latitude) and (latitude,longitude) input and/or output. [Default is (longitude,latitude)]. Append i to select input only or o to select output only. [Default affects both].
| −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 −W0.25p,red −Ggreen −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
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.

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(1), psbasemap(1), psxy(1)

## 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)