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Re: extract circle from data with idl [message #94781 is a reply to message #94780]

Wed, 11 October 2017 05:41

Markus Schmassmann
Messages: 129
Registered: April 2016

Senior Member

On 10/11/2017 02:23 PM, termybel@gmail.com wrote:
> How can extract an circle or an ellipse from my data with IDL?
> With a contour plot my data form a circle, I need to know the center
> of this circle. From the geometry I know that if I know 3 points I
> can extract a circle, are there routine or function something else in
> IDL that using, reading my data, can give me the center?

;; without using the properties of the circle or ellipse:

; DATA being the data to be contoured
data=2-(([-1:1:.1]^2)#replicate(1.,21))-(replicate(1.,21)#([ -1:1:.1]^2))
; LEVEL the appropriate level to contour
level=1.
contour, data, path_info=li, path_xy=lines, /path_data_coord, $
levels=[level], /path_double
if n_elements(li) ne 1 then message, 'not exactly 1 contour'

cont_obj =obj_new('IDLanROI',lines)
void= cont_obj.ComputeGeometry(centroid=center)

print, center[0:1]

;; otherwise use math to calculate the center

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[Message index]

		extract circle from data with idl By: termybel on Wed, 11 October 2017 05:23
		Re: extract circle from data with idl By: Markus Schmassmann on Wed, 11 October 2017 05:41
		Re: extract circle from data with idl By: termybel on Thu, 12 October 2017 05:10
		Re: extract circle from data with idl By: Markus Schmassmann on Thu, 12 October 2017 07:27
		Re: extract circle from data with idl By: termybel on Sun, 15 October 2017 08:43
		Re: extract circle from data with idl By: termybel on Sun, 15 October 2017 09:08
		Re: extract circle from data with idl By: Markus Schmassmann on Mon, 16 October 2017 02:20
		Re: extract circle from data with idl By: termybel on Mon, 16 October 2017 03:23
		Re: extract circle from data with idl By: Helder on Wed, 11 October 2017 05:47

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