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Re: Overlaying a contour on a small image [message #58979]

Fri, 29 February 2008 12:31

wlandsman
Messages: 743
Registered: June 2000

Senior Member

On Feb 29, 1:41 pm, David Fanning <n...@dfanning.com> wrote:
> Isn't this what you want:
>
> im = dist(9)
> thispostion = [0.1, 0.1, 0.9, 0.9]
> TVIMAGE, bytscl(im), POSITION=thisPosition, /KEEP_ASPECT_RATIO, $
> /NOINTERP, /ERASE
> contour,im, Position=thisPosition,/xsty,/ysty,/noerase,$
> scale_vector(findgen(9), 0, 9), scale_vector(findgen(9), 0, 9)
>

I don't think any type of scaling is going to work. (The above
example does not match the contour overlay with the single high
pixel.) The point is that there really is no contour information at
the half-pixel edges, since contours depend on the change between
pixels. (You can display an image of 1 pixel, but you can't contour
1 pixel.) The program sent by Paolo (thanks!) works by not
displaying the outer half pixel where there is no contour
information. I actually like this approach.

The ISOCONTOUR routine looks like it could be used to extrapolate
contours to the outer half pixel, perhaps in an easier way than the
PATH_XY keyword to CONTOUR.

Cheers, --Wayne

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[Message index]

		Re: Overlaying a contour on a small image By: wlandsman on Fri, 29 February 2008 12:31
		Re: Overlaying a contour on a small image By: pgrigis on Fri, 29 February 2008 11:15
		Re: Overlaying a contour on a small image By: David Fanning on Fri, 29 February 2008 11:06
		Re: Overlaying a contour on a small image By: David Fanning on Fri, 29 February 2008 10:41

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