Re: [Plplot-devel] proposal for consideration: plcont_phase.c for contour plots of phase data

[David M. <da...@as...>]

Hi, Maurice and Alan,

On Apr 20, 2010, at 0:39 , Maurice LeBrun wrote:

> The general remapping of coordinates is a crucial part of it.

I think you are referring to the 0/2pi coordinate "seam" when  
transforming a rectilinear grid to a polar grid.  I think Ed (correct  
me if I'm wrong, Ed) is referring to a different problem of  
contouring the phase (i.e. angle or arg) of complex data values  
regardless of the grid type (i.e. rectilinear or polar).

One approach I've taken in the past when visualizing 2d complex data  
fields (and would like to add to plsurf3d et al) is to make a surface  
plot with z values based on the amplitudes and color values based on  
the phase.  Using the phase as the hue component of HSL (or HSV)  
makes for a nice colorization that handles phase wrapping  
intrinsically since the HSL "color wheel" wraps smoothly itself.   
Unfortunately, this "trick" doesn't help for contouring data.

Dave