Re: Plotting a 3D Array In IDL

[Paul van Delst <paul.vandelst(at)noaa.gov>]

eddie haskell wrote:
> 
> > Say I have a 3D array whose elements are only 1 or 0. I'd like to plot
> > this array, say a white dot for the 1's and a red dot for the 0's. Is there
> > a way I can do this in IDL?
> 
> Below is a program fragment that does what I think you want done.  There might
> be a slick one line way of doing it or maybe something visually stunning using
> object graphics but nothing currently leaps to mind.
> 
> Cheers,
> eddie
> 
> ;--------------------------
> n = 4
> a = randomu(seed,n,n,n) gt 0.5
> surface, dist(n), /nodata, zr=[0,n-1], /save
> tvlct,[0,255],[255,0],[0,0],1
> 
> for j = 0,1 do begin
>   wh = where(a eq j)
>   x = wh mod n
>   y = wh / n mod n
>   z = wh / n^2
>   for i = 0, n_elements(wh)-1 do $
>     plots,x[i],y[i],z[i],/t3d,psym=2,color=j+1
> endfor
> ;-----------------------

Cool - I couldn't figure out how to do it. I modified the above a little to use plot3d 

n = 4
a = randomu(seed,n,n,n) gt 0.5
tvlct,[0,255],[255,0],[0,0],1

for j = 0,1 do begin
  wh = where(a eq j)
  x = wh mod n
  y = wh / n mod n
  z = wh / n^2
  plot3d, x,y,z,psym=2,color=j+1,oplot=j
endfor

but I find the resultant plot hard to interpret. I think this is a case where object
graphics is required to give some depth to the plot by varying the size of the plotting
symbols with perceived depth... or something like that.

paulv

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