psvelo - Plot velocity vectors, crosses, and wedges on maps
psvelo [ table ] -Jparameters -Rregion [ -Aparameters ] [ -B[p|s]parameters ] [ -Fcolor ] [ -Ecolor ] [ -Gcolor ] [ -K ] [ -L ] [ -N ] [ -O ] [ -P ] [ -Ssymbol/scale/conf/font_size ] [ [ -U[just/dx/dy/][c|label] ] [ -V[level] ] [ -Wpen ] [ -Xx_offset ] [ -Yy_offset ] [ -ccopies ] [ -di<nodata> ] [ -h<headers> ] [ -i<flags> ] [ -:[i|o] ]
Note: No space is allowed between the option flag and the associated arguments.
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 It has been replaced by psvelo and psmeca.
-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, 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, 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, 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, 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, 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.
-X[a|c|f|r][x-shift[u]]
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. Below, left and right refers to the side of the vector line when viewed from the start point to the end point of the segment:
+aangle sets the angle of the vector head apex [30].
+b places a vector head at the beginning of the vector path [none]. Optionally, append t for a terminal line, c for a circle, or a for arrow [Default]. Further append l|r to only draw the left or right side of this head [both sides].
+e places a vector head at the end of the vector path [none]. Optionally, append t for a terminal line, c for a circle, or a for arrow [Default]. Further append l|r to only draw the left or right side of this head [both sides].
+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 of specified heads [both sides].
+m places a vector head at the mid-point the vector path [none]. Append f or r for forward or reverse direction of the vector [forward]. Optionally, append t for a terminal line, c for a circle, or a for arrow head [Default]. Further append l|r to only draw the left or right side of this head [both sides]. Cannot be combined with +b or +e.
+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 data instead represent the start and stop opening angles of the arc segment relative to the given point.
+r draws half-arrows, using only the right side of specified heads [both sides].
t[b|e]trim will shift the beginning or end point (or both) along the vector segment by the given trim; append suitable unit. If the modifiers b|e are not used then trim may be two values separated by a slash, which is used to specify different trims for the two ends. Positive trims will shorted the vector while negative trims will lengthen it [no trim].
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.
Finally, Cartesian vectors may take these modifiers:
+zscale[unit] expects input dx,dy vector components and uses the scale to convert to polar coordinates with length in given unit.
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
Bomford, G., Geodesy, 4th ed., Oxford University Press, 1980.
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