Re: Index of a sector

[Med Bennett <mbennett(at)indra.com>]

How about this?

IDL> junk=dist(200)
IDL> w = where(junk le 50.)
IDL> w = w[where(w mod 200 le 100 and w/200 le 100)]
IDL> junk2 = bytarr(200,200)
IDL> junk2[w] = 1
IDL> bytscl,junk2

"Pavel A. Romashkin" wrote:

> Hi,
>
> I tried to solve this yesterday, but it gave me a headache. I tried
> again today, but the headache is back and I did not get any closer to
> the solution. It is very simple. Well after all, what can you ask from a
> Mac user.
>
> If you have a (square) 2D array, let's say, DIST(200, 200), how to
> obtain the index of points enclosed by a sector of a given radius, drawn
> from the corner of the array (point [0, 0])? Foe instance, radius 50?
> So, I will have
>
> 0,1,2,...50
> 101,102,...,149 (or so)
> 201,202,...
> ...
> 501,...?
>
> I thought to try to cut all corners and use IDLanROI, but for some
> reason, I think that JD or Craig have the answer ready. Besides, David
> tried anROI... how can I dream of succeeding where the Titan (read:
> Coyote) failed?
> Thanks,
> Pavel