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Re: 3D Scatter plot [message #13935 is a reply to message #642]

Wed, 23 December 1998 00:00

David Borland
Messages: 6
Registered: December 1998

Junior Member

Hellu,
An easy way of doing this is to include the psym keyword in the plot_3dbox
call. If you include this command with a positive integer between 1and 7 you
will get just the points drawn, if you use a negative integer between -1 and
-7, you will get the points and the lines drawn.
One way of getting a surface plot from x,y,z coordinates is to call
triangulate, which will give you daleany triangles for the object, and then
send that output to trigrid, which does something else to the data, and then
take that output and do a surface plot to it.

Ie. triangulate,image_x,image_y,angles
griddata=trigrid(image_x,image_y,image_z,angles)
surface,griddata

angles is where triangulate stores it's results.

If you want to see what triangulate has done, try this set of commands and it
will draw out the triangles for you.
triangulate,image_x,image_y,angles
for j=0,n_elements(angles[0,*])-1 do begin
t = [angles[*,j],angles[0,j]]
plots,image_x[t],image_y[t],image_z[t],/t3d,color='ff0000'x

A problem with this method is that if you are trying this on a 3D shape, you
will get lines that cross through the shape and make the surface plot look
wrong. I have not figured out how to fix this with built in IDl routines, so
I'm trying to write my own. If anyone knows a better way of doing this part,
I'd love to hear it.

--
David Borland
Electrical Geodesics Inc.
davidbor@cyber-dyne.com

"Patrick V. Ford" wrote:

> I want a 3D display of a set of data point that I have imported from a
> SYLK file. I have extracted from the SYLK structure the X, Y and Z
> coordinates, where each is an array of 117 float. I get close to what I
> want with a plot-3dbox function, but because of the way it is formatted it
> looks like a series of switch-back paths. What I would really like is a
> surface plot, but I failed at my attempt to use these functions. It is
> also obvious that I don't have a clue on how to set the exponential
> parameter in KRIG2D. I know there must be some trivial method to do this
> in IDL.
>
> Thanks in advance.
>
> Patrick Ford, MD
> Baylor College of Medicine
> pford@bcm.tmc.edu

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[Message index]

		3d scatter plot By: li on Wed, 16 December 1992 17:17
		Re: 3D scatter plot By: landers on Tue, 25 May 1993 06:07
		Re: 3D scatter plot By: Bruce E Thomason on Thu, 13 June 1996 00:00
		Re: 3D scatter plot By: peter on Thu, 13 June 1996 00:00
		Re: 3D Scatter plot By: David Borland on Wed, 23 December 1998 00:00
		Re: 3D Scatter Plot By: David Fanning on Thu, 06 April 2006 13:27
		Re: 3D Scatter Plot By: aecorner on Thu, 06 April 2006 13:09
		Re: 3D Scatter Plot By: ChiChiRuiz@gmail.com on Thu, 06 April 2006 09:41
		Re: 3D Scatter Plot By: ChiChiRuiz@gmail.com on Thu, 06 April 2006 09:39
		Re: 3D Scatter Plot By: David Fanning on Thu, 06 April 2006 08:59
		Re: 3D Scatter Plot By: David Fanning on Thu, 06 April 2006 07:12

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