vecplot

(./FEM/vecplot.m)

Function Synopsis

retval=vecplot(varargin)

Help text

VECPLOT routine to plot vectors.  
 VECPLOT draws vectors on the current figure, at (x,y)
 locations determined in one of two ways.  If the first
 argument to VECPLOT is a fem_grid_struct, then VECPLOT
 extracts the FEM domain coordinates as the vector origins.
 Otherwise, the user supplies the (x,y) coordinates
 explicitly.  This flexibility exists because vector
 plotting does not require any knowledge of nodal 
 connectivity, and perhaps the (u,v) data are not
 from a FEM model output.

 VECPLOT scales the magnitude of 
 (u,v) by the magnitude of max(abs(u,v)) and then 
 forces a vector of magnitude sc to be 10% of the x data
 range.  By default, sc = 1., so that a 1 m/s vector will
 be scaled to 10% of the x data range.  If sc=.5, then
 a vector magnitude of 50 cm/s  will be scaled to 10% of the 
 x data range.  Decreasing sc serves to make the vectors
 appear larger.  VECPLOT then prompts the user to place
 the vector scale on the figure, unless scale_xor,scale_yor
 is specified (see below).
      
   INPUT:   fem_grid_struct  (from LOADGRID, see FEM_GRID_STRUCT)
            OR
            x,y    - vector origins
            u,v    - vector amplitudes
            These inputs are optional, but if one is needed, all
            preceeding it wil be required.
            sc     - vector scaler; (optional; default = 1.)
            sclab  - label for vector scale; (optional; default = 'cm/s')
            scale_xor,scale_yor  -  location to place vector scale

  OUTPUT:   h - vector of handles to the vector lines drawn, the 
                scale vector, and the scale vector text.

   NOTES:   VECPLOT requires atleast 2 coordinates and vectors.

    CALL:   hv=vecplot(x,y,u,v,sc,sclab)
     or
            hv=vecplot(fem_grid_struct,u,v,sc,sclab)

 Written by : Brian O. Blanton

Cross-Reference Information

is_valid_struct./FEM/is_valid_struct.m