       HELP with ListPlotVectorField[]

• To: mathgroup at smc.vnet.net
• Subject: [mg4869] HELP with ListPlotVectorField[]
• From: dave at siqin.feinberg.nwu.edu
• Date: Thu, 26 Sep 1996 22:42:23 -0400
• Organization: Northwestern University, Evanston, IL, US
• Sender: owner-wri-mathgroup at wolfram.com

```About a week or two ago I posted a similar problem, so please read through or ignore upon your interest!

I need help with ListPlotVectorField[] or recreating a variation of it.

What I would ideally like is to have options to ListPlotVectorField[] that are a list that can vary the radius of a circle drawn around the head of each vector arrow head.   Also I'd like an option that would be a list that could vary the grayscale or color of each vector.

What I'm doing is summing many vector fields and I would like the radius of the circles to represent the standard deviation of that particular vectors elements.

something like (please forgive the ASCII graphics)

(  ^ )
/           ------
/         (      ^       )
/                    \
/                        \
/                            \

What I've tried is something like this:
vectorMatrix = {};
Do[
g = {
Arrow[{x,y}, {x2,y2}],
Line[{{x,y}, {x2, y2}}],
GrayLevel[sd[[x]][[j]] ],
Circle[{x2,y2}, sd[[x]][[y]] ]
};
vectorMatrix = Append[vectorMatrix, g];
,{x, 1, noColumns}, {y, 1, noRows}]
Show[Graphics[vectorMatrix]]

Unfortunately the visual look is not correct and that's where I'd like some help.  {x2,y2} are a value that represents a vector (x,y) whose origin is at (0,0).

I have a web page set up with the actual Mma code at http://siqin.feinberg.nwu.edu/Served/tmp/myVectorPlot.html
I know my code is terrible so please resist the temptation to slam me.  I am not very familiar with Mma programming particularly with its graphics primitives so please HELP!!!!!