plv: Plot a Vector Field

Calling Sequence

...

plv(vy, vx[, y, x][, ireg][, <keylist>])

7#7

Description

Plot a vector field (vx, vy) on the mesh (x, y). y, x, and ireg are as for plm. The vy and vx arrays must have the same shape as y and x. The y, x, and ireg arguments may all be omitted to default to the mesh set by the most recent plmesh call.

Keyword Arguments

The following keyword argument(s) apply only to this function.

scale = dt

The scale keyword is the conversion factor from the units of (vx, vy) to the units of (x, y) -- a time interval if (vx, vy) is a velocity and (x, y) is a position -- which determines the length of the vector ``darts'' plotted at the (x, y) points.

If omitted, scale is chosen so that the longest ray arrows have a length comparable to a ``typical'' zone size. You can use the scalem keyword in pledit to make adjustments to the scale factor computed by default.

hollow = 0/ 1 
aspect = <float value>

Set the appearance of the ``darts'' of a vector field plot. The default darts, hollow= 0, are filled; use hollow= 1 to get just the dart outlines. The default is aspect= 0.125; aspect is the ratio of the half-width to the length of the darts. Use the color keyword to control the color of the darts.

The following additional keyword arguments can be specified with this function. legend, hide, type, width, color, smooth, marks, marker, mspace, mphase, triangle, region

See ``Plot Function Keywords'' on page  for detailed descriptions of these keywords.

Example

This example applies to the same mesh that we have considered in the last three examples.

plv(x+. 5, y-. 5)

The plot appears on the next page.