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Re: Number of points inside a contour curve [message #52031 is a reply to message #51944]

Thu, 21 December 2006 07:38

burkina
Messages: 32
Registered: February 2005

Member

On Dec 20, 3:58 pm, David Fanning <n...@dfanning.com> wrote:
> I note that HISTOGRAM_2D uses embedded FOR loops and that HIST_2D
> is written by JD Smith. That's enough for me. :-)

Ok, I'm using hist_2d. The results are similar, I was wrong...

> If you did a HISTOGRAM on the result of HIST_2D, then I should
> think you could find the level where a cumulative total of
> the HISTOGRAM result was 90% of the total (VALUE_LOCATE
> might be handy here). I'm mostly thinking out loud. There
> seem to be a few details missing here....But I think this
> might be a promising direction. :-)

Indeed, your suggestion to use histogram was good. However, I don't
need VALUE_LOCATE. This is how I solved the problem:

;density is the result from HIST_2D

maxvalue=max(density,maxpoint)
maxcoord=ARRAY_INDICES(density,maxpoint)
max_x=xmin+maxcoord[0]*xbinsize+xbinsize/2
max_y=ymin+maxcoord[1]*ybinsize+ybinsize/2
print, 'The maximum density is: ', maxvalue
print, 'It occurs at coordinates:'
print, max_x, max_y

tot_histo=total(density)
histoden=histogram(density)
n_histo=n_elements(histoden)
sum=0
k=0

while sum lt 0.9*tot_histo do begin

sum = sum + histoden[n_histo-1-k] * (maxvalue-k)
k = k+1

endwhile

maxlevel=histoden[n_histo-1-k] * (maxvalue-k)

contour, density, xabscissa,yabscissa,c_colors=fsc_color('red'),
levels=maxlevel, /overplot
xyouts, max_x, max_y, '+', /data, color=fsc_color('red')

Stefano

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[Message index]

		Re: Number of points inside a contour curve By: David Fanning on Wed, 20 December 2006 06:58
		Re: Number of points inside a contour curve By: burkina on Thu, 21 December 2006 07:38
		Re: Number of points inside a contour curve By: JD Smith on Fri, 29 December 2006 14:20

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