Re: How to do polar plots with logarithmic axis in radial coordinate?

• Subject: Re: How to do polar plots with logarithmic axis in radial coordinate?
• From: Charlie Zender <zender(at)uci.edu>
• Date: Tue, 06 Feb 2001 18:11:07 -0800
• Newsgroups: comp.lang.idl-pvwave
• Organization: University of California at Irvine
• References: <3A802C71.1070002@uci.edu> <on7l33fpp7.fsf@cow.physics.wisc.edu>
• User-Agent: Mozilla/5.0 (X11; U; Linux 2.2.16-22 i686; en-US; m18) Gecko/20001205
• Xref: news.doit.wisc.edu comp.lang.idl-pvwave:23408

```Craig Markwardt wrote:

> Could you simply take the ALOG10() logarithm of the data before
> plotting it?  Easier to re-label the axis than re-invent the world...
>

This would cause the radial coordinate to be negative-valued which
would have unpleasant results. It's possible someone could get
this method to work but I tried without success.

> Good luck,
> Craig
>
>
> Charlie Zender <zender@uci.edu> writes:
>
>
>> Hi,
>>
>> I am wondering if anyone has tried to plot higly peaked polar
>> coordinate data. I am referring to data that are a function of
>> angle (-pi to pi) where the data are very sharply peaked in
>> some direction, so much so that the radial coordinate must
>> be logarithmic in order to display the data. The so-called
>> scattering phase function of small particles is the exact
>> application where I have run into this problem. Using /polar
>> on a regular call to plot, as recommended by the user's guide
>> and by Fanning's hints page, only seems to work well when the
>> x-axis is not set to be logarithmic. Very weird things begin
>> to happen when setting the xlog=1 or ylog=1 keywords when /polar
>> is set.
>>
>> The data span five decades from 1.0e-5 to 1.0.
>> If anyone can tell me how to make this look in polar coordinates
>> I'd be very grateful. Ideally the solution will a polar coordinate
>> plot where the radial coordinate is logarithmic, and thus has
>> a "hole" around the origin (so the minimum plotted coordinate could
>> be, e.g., 10^-6). But I'm open to anything that looks good.
>>
>> Thanks,
>> Charlie
>> --
>> Charlie Zender zender@uci.edu (949) 824-2987/FAX-3256, Department of
>> Earth System Science, University of California, Irvine CA 92697-3100
>>

--
Charlie Zender zender@uci.edu (949) 824-2987/FAX-3256, Department of
Earth System Science, University of California, Irvine CA 92697-3100

```