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Re: Number of points within a rectangular region [message #36838]

Sat, 01 November 2003 11:13

Paul Sorenson
Messages: 48
Registered: May 2002

Member

Have you taken a look at IDLanROI::ContainsPoints() ? That routine might be
useful for you even if you are not doing object graphics. It can tell you
if a point is exterior to a region, interior to a region, on edge or on
vertex.

-Paul Sorenson

"Isa Usman" <eepisu@bath.ac.uk> wrote in message
news:bnu9ng$10h6@newton.cc.rl.ac.uk...
> Hello,
>
> I'm trying to get the indices to the points that fall within a rectangular
> region. I'm aware of David Fanning's INSIDE routine that does this but
> because I have got 100,000 points its going to involve a lot of looping.
So
> I decided to use the HIST_ND with reverse indices but its not giving me
the
> right results. What am I missing?
>
> Thanks in advance.
>
> Isa
>
> IDL> x = [0.5,-0.5,-0.5,0.5]
>
> IDL> y = [0.5,0.5,-0.5,-0.5]
>
> IDL> z = transpose([[x],[y]])
>
> IDL> result = hist_nd(z,min = [0,0], max = [1,1], nbins = 1,
reverse_indices
> = ri)
>
> print, ri[ri[0]:ri[1]-1]
>
> 0 1 2 3
>
>

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[Message index]

		Re: Number of points within a rectangular region By: Paul Sorenson on Sat, 01 November 2003 11:13
		Re: Number of points within a rectangular region By: wmconnolley on Sat, 01 November 2003 06:58
		Re: Number of points within a rectangular region By: btt on Fri, 31 October 2003 10:50

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