| Re: Using contour procedure to extract specific regions [message #71937] |
Wed, 28 July 2010 09:21 |
S. Murray
Messages: 6
Registered: July 2010
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Junior Member |
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On Jul 28, 1:29 pm, David Fanning <n...@dfanning.com> wrote:
> S. Murray writes:
>> Then, I was reading this page:http://www.dfanning.com/map_tips/contoshape.html
>> , and from that gathered that my first 'step' should be:
>
>> contour, data,level=130,PATH_INFO=info, PATH_XY=xy, XSTYLE=1,
>> YSTYLE=1,/PATH_DATA_COORDS
>
>> But, after reading the 'contour.pro' explanation on the IDL webpage, I
>> still dont understand exactly what is contained within path_info etc
>> to know what to do next! How do I create image plots with these
>> outputs like the one on the webpage?
>
> I think I would take a different approach. Here are
> a couple of articles that describe how I handled
> a very similar problem in "blob analysis" and the
> programs I wrote to do the job:
>
> http://www.dfanning.com/ip_tips/boundary.html
> http://www.dfanning.com/ip_tips/blobanalysis.html
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
Thanks very much for that, a much more understandable method! Works
perfectly.
For future searchers, I created a mask and then ran 'blob_analyser' on
my image. Then just selected which 'blob' I wanted using 'GetStats'
and plotting the stats.perimeter_pts arrays using 'plots'.
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| Re: Using contour procedure to extract specific regions [message #71947 is a reply to message #71937] |
Wed, 28 July 2010 05:29  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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S. Murray writes:
> Then, I was reading this page: http://www.dfanning.com/map_tips/contoshape.html
> , and from that gathered that my first 'step' should be:
>
> contour, data,level=130,PATH_INFO=info, PATH_XY=xy, XSTYLE=1,
> YSTYLE=1,/PATH_DATA_COORDS
>
> But, after reading the 'contour.pro' explanation on the IDL webpage, I
> still dont understand exactly what is contained within path_info etc
> to know what to do next! How do I create image plots with these
> outputs like the one on the webpage?
I think I would take a different approach. Here are
a couple of articles that describe how I handled
a very similar problem in "blob analysis" and the
programs I wrote to do the job:
http://www.dfanning.com/ip_tips/boundary.html
http://www.dfanning.com/ip_tips/blobanalysis.html
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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| Re: Using contour procedure to extract specific regions [message #71951 is a reply to message #71947] |
Wed, 28 July 2010 04:52 |
S. Murray
Messages: 6
Registered: July 2010
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Junior Member |
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On Jul 28, 12:41 pm, "S. Murray" <murray_sop...@hotmail.com> wrote:
> I have a data array of an inclination angle, ranging from 0 to
> 180degrees, which when I plot an image of it shows about 3 specific
> regions that are greater than 130degrees. They basically look like
> 'blobs' on the image map. I need to specifically analyse one of the
> '130degree contour' blobs, not every single region picked out by
> simply contouring at level = 130. I will be analysing this specific
> location, taking averages, min, max, etc, in order to track it's
> changes over several different scans (I'm just looking at the first
> one for the moment). Also will need to plot images of it contoured on
> it's own on the map, rather than having everything else contoured as
> well. I am becoming very confused about how to go about it!
>
> First I thought I would try to look at it with all areas above
> 130degrees, and if that worked I could move onto more specific
> locations:
>
> thresh= data GE 130
> pmm,data*(thresh)
> 0.00000 174.172
>
> So, the result goes from 0 to 174, including the now '0' value area
> and that would be useless if I want to average the specific regions.
> So I abandoned this route.
>
Actaully, I just realised what I was doing wrong here (quite obvious
now I see). If I just 'pmm,data > 130' that'll show me the values. But
I am still unaware how to extract a region with the contouring
below...
> Then, I was reading this page:http://www.dfanning.com/map_tips/contoshape.html
> , and from that gathered that my first 'step' should be:
>
> contour, data,level=130,PATH_INFO=info, PATH_XY=xy, XSTYLE=1,
> YSTYLE=1,/PATH_DATA_COORDS
>
> But, after reading the 'contour.pro' explanation on the IDL webpage, I
> still dont understand exactly what is contained within path_info etc
> to know what to do next! How do I create image plots with these
> outputs like the one on the webpage?
>
> Basically, I need to figure out how do I use this information to
> 'segment' my data, and thus can plot a new image with just this region
> and also analyse it, but I'm stumped at this point and not sure which
> direction to take. What would be my next step in this process? Any
> help would be greatly appreciated, I've been staring at this for too
> long now!
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