Vector Field Plots

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Thu, 10/16/2008 - 02:24 pm

Is there any good built-in way to do a vector field plot in Igor?
It really depends on the dimensionality in question. In IP6 there is a demo experiment for a 3D vector field. Go to File Menu->Example Experiments->Visualization->Advanced->Scatter Arrows. A 2D example is in File Menu->Example Experiments->Graphing Techniques->Arrow Plot.

HTH,

A.G.
WaveMetrics, Inc.

October 17, 2008 at 09:39 am - Permalink

Let me add my support to the (implicit) request here. I have looked at the "Arrow Plot" demo, and it is far too complicated to be useful in practice. What is needed is a plot type analogous to "Contour Plot"s, which would just need a matrix and then be able to make a quick plot, with a dialog to adjust appearance.

John Bechhoefer

February 4, 2009 at 01:53 pm - Permalink

bech wrote:
Let me add my support to the (implicit) request here. I have looked at the "Arrow Plot" demo, and it is far too complicated to be useful in practice. What is needed is a plot type analogous to "Contour Plot"s, which would just need a matrix and then be able to make a quick plot, with a dialog to adjust appearance.

John Bechhoefer


What's the usual data format for the 2D vector plot?

A 2D complex matrix?

For "adjust appearance" is there much beyond a scale factor for the vector lengths?

February 9, 2009 at 08:11 pm - Permalink

JimProuty wrote:
bech wrote:
Let me add my support to the (implicit) request here. I have looked at the "Arrow Plot" demo, and it is far too complicated to be useful in practice. What is needed is a plot type analogous to "Contour Plot"s, which would just need a matrix and then be able to make a quick plot, with a dialog to adjust appearance.

John Bechhoefer


What's the usual data format for the 2D vector plot?

In the Igor context, it would either be a function, a REAL matrix, or possibly a set of XY pairs. Igor would then have to do some work to numerically estimate the local gradient and then come up with the arrow. This would be a task analogous to the work required to figure out contours in a contour plot. (Indeed, the arrows are, of course, just locally perpendicular to contours, so the same routines might be used in both.) On the same topic, a streamline option would also be useful. (This is a plot of lines that are generated by "connecting the arrows all together to form a curve" and are, again, perpendicular to contour plots. They correspond to integrating the 2d-ODE associated with the vector field.)

A 2D complex matrix?
Not usually, but perhaps an option.

For "adjust appearance" is there much beyond a scale factor for the vector lengths?


Well, there would be color and other graphics parameters (thickness, arrow-head shape, etc.) for the arrows themselves (+ option to have either just lines (no arrow heads) or "nails" (flat heads) are also useful. For streamlines, all the options in contour plots would be useful.

John Bechhoefer

February 13, 2009 at 05:45 pm - Permalink

We finally had a need to do a vector-field plot. The built-in option that now exists is great! (Confession -- at first, it didn't work; then I actually read the help file carefully and realized that the length units are points, not the graph xy units, and also that 2d wave format is r-theta and not xy. After that, it was smooth sailing.)

Belated thanks to the Igor folks for adding this!

February 17, 2012 at 12:15 pm - Permalink

I think the built-in option was "Wind Barbs":

DisplayHelpTopic "Wind Barb Plots"

 

January 14, 2024 at 07:05 pm - Permalink