| Re: how to draw streamline [message #59290 is a reply to message #59208] |
Mon, 17 March 2008 14:52   |
mankoff
Messages: 131
Registered: March 2004
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Senior Member |
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On Mar 17, 10:27 am, "mgal...@gmail.com" <mgal...@gmail.com> wrote:
> On Mar 16, 11:22 pm, wfz...@bjmb.gov.cn wrote:
>
>
>
>> On 3月14日, 上午4时32分, Chris Torrence <gorth...@gmail.com> wrote:
>
>>> On Mar 7, 7:55 am, "Kenneth P. Bowman" <k-bow...@null.edu> wrote:
>
>>>> In article
>>>> < 92bef8cb-bd54-48b7-b54c-2ff9f4f75...@s8g2000prg.googlegroups .com >,
>
>>>> wenfang_z...@hotmail.com wrote:
>>>> > Hi,all
>>>> > I want to draw the wind streamline map,and I try many methods
>>>> > described in the forum, but some are wind vectors not the streamline,
>>>> > which is the serial contour line with arrow on the contour plot.
>
>>>> > some one ever mentioned that there was a script sample on the web site
>>>> >http://www.metvis.com.au/idl/
>>>> > but i can't get access to it.
>
>>>> > so if there anybody who can load that web site and give a copy of both
>>>> > the script and the streamline image for me?
>
>>>> > I will appreciate your help!
>
>>>> > wenfang
>
>>>> Here is a sample code to plot 2-D streamlines using VEL.
>
>>>> By default VEL chooses the initial points randomly, but the
>>>> source code is available if you want to change that.
>
>>>> Ken Bowman
>
>>>> PRO STREAMLINE_DEMO
>
>>>> n = 50
>>>> x = FINDGEN(n)/(n-1)
>>>> y = FINDGEN(n)/(n-1)
>
>>>> xx = REBIN(x, n, n)
>>>> yy = REBIN(REFORM(y, 1, n), n, n)
>
>>>> u = -SIN(!PI*xx)*COS(!PI*yy)
>>>> v = COS(!PI*xx)*SIN(!PI*yy)
>
>>>> VEL, u, v, NVECS = 100, NSTEPS = 100, length = 0.5
>
>>>> END
>
>>> Following on from Ken's example, you might also try,
>
>>> iVector, u, v, x, y, /STREAMLINES, STREAMLINE_NSTEPS=25
>
>>> -Chris
>>> ITTVIS- 隐藏被引用文字 -
>
>>> - 显示引用的文字 -
>
>> thanks for all response from you.
>> now I am a litttle comfused, what kind of line can be called as wind
>> streamline?
>> what I want is the consecutive line with arrow, something like the
>> contour plot line with arrow, not the small lines with arrow,I don't
>> know how to describe it more clear? I have a sample image of wind
>> streamline ,which is what I want, but how I can put it on the forum so
>> all of you can have a look and understand what I mean.
>
> I think you are talking about OSTR (image-guided streamlines) in this
> diagram:
>
> http://michaelgalloy.com/wp-content/uploads/2008/03/flow.png
>
> I have thought about making implementations of some of the
> visualizations in that diagram. I have a (very slow) implementation
> for LIC:
>
> http://michaelgalloy.com/2007/12/09/lic-flow-code.html
>
> Mike
> --www.michaelgalloy.com
> Tech-X Corporation
> Software Developer II
Are all 6 images the same data? It looks like it, but it really shows
some of the limitations of a simple vector field graphic... Wow.
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