| polar contour plots [message #26116] |
Fri, 03 August 2001 07:58  |
ahw199
Messages: 6
Registered: July 2001
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Junior Member |
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I am a relatively new user of IDL and I am trying to make a ploar
plot. I have written a programme which does exactly that but does not
give me the expected pattern. I only have data for every 10 degrees
around the circle, could this be my problem? i.e. do I need data for
every degree around the plot for the contours to be accurate?
thanks
Ann Webber
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| Re: polar contour plot [message #69352 is a reply to message #26116] |
Mon, 04 January 2010 09:49  |
Hassan
Messages: 48
Registered: October 2009
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Member |
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On Dec 30 2009, 2:12 pm, David Fanning <n...@dfanning.com> wrote:
> Hassan writes:
>> I have 3 arrays, a zenith angle array, a azimuth angle array and DN
>> values. each DN is related to specific zenith and azimuth. I need to
>> draw a contour of DNs on polar plot which is a circle as the distance
>> from the center of the circle is zenith and distance from North is
>> azimuth . I assume there should be a .pro file or sth that does this
>> work. I used polar_contour but I think I need to add other commands to
>> get the desired results.
>> any help would be appreciated.
>
> Your assumption that there should be a procedure for this
> is a good one, even if it turns out to be entirely wrong.
> I think thing this is one of those should-be-easy-turns-
> out-to-be-hard situations in IDL. (Normally, things are
> the other way around, thank goodness.)
>
> I would approach this problem by setting up a Lambert
> Equal-Area map projection and drawing my contour plot
> on that, after scaling my data to the appropriate
> lat/lon values. This will mean you will have to do
> your own plot annotation (with PLOTS and XYOUTS,
> typically), but I don't think this will be particularly
> difficult.
>
> 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 David for the help. i think i need to work out how i can scale
the zenith and azimuth angles based on lat/long.
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| Re: polar contour plot [message #69362 is a reply to message #26116] |
Wed, 30 December 2009 06:12 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Hassan writes:
> I have 3 arrays, a zenith angle array, a azimuth angle array and DN
> values. each DN is related to specific zenith and azimuth. I need to
> draw a contour of DNs on polar plot which is a circle as the distance
> from the center of the circle is zenith and distance from North is
> azimuth . I assume there should be a .pro file or sth that does this
> work. I used polar_contour but I think I need to add other commands to
> get the desired results.
> any help would be appreciated.
Your assumption that there should be a procedure for this
is a good one, even if it turns out to be entirely wrong.
I think thing this is one of those should-be-easy-turns-
out-to-be-hard situations in IDL. (Normally, things are
the other way around, thank goodness.)
I would approach this problem by setting up a Lambert
Equal-Area map projection and drawing my contour plot
on that, after scaling my data to the appropriate
lat/lon values. This will mean you will have to do
your own plot annotation (with PLOTS and XYOUTS,
typically), but I don't think this will be particularly
difficult.
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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