[manual] suggested addition to pcolor description

[Ben Abbott]

On Sep 20, 2008, at 12:07 PM, Francesco Potorti` wrote:

> More generally speaking, none of the issues that I mentioned above are
> addressed by this change.

opps ... you are correct. I can do a better job.

I believe I've incorporated your points (except for #3, as it is  
backend specific). I've also made a change to the doc strings in  
imagesc.

 > help pcolor
  -- Function File:  pcolor (X, Y, C)
  -- Function File:  pcolor (C)
      Density plot for given matrices X, and Y from `meshgrid' and  a
      matrix C corresponding to the X and Y coordinates of  the mesh's
      vertices. If X and Y are vectors, then a typical vertex  is (X(j),
      Y(i), C(i,j)).  Thus, columns of C  correspond to different X
      values and rows of C correspond  to different Y values.

      The `colormap' is scaled to the extents of C.   Limits may be
      placed on the color axis by the  command `caxis', or by setting
      the `clim' property of the  parent axis.

      The face color of each cell of the mesh is determined by
      interpolating  the values of C for the cell's vertices. `imagesc'
      may be used  to set the face color of the cells explicitly.

      `shading' modifies an attribute determining the manner by which  
the
      face color of each cell is interpolated from the values of C,  and
      the visibility of the cells' edges. By default the attribute is
      "flat", which renders a single color for each cell's face with the
      edge  visible.

      H is the handle to the surface object.

      See also: caxis, contour, meshgrid, meshsc, shading.