| Re: how to draw streamline [message #59276 is a reply to message #59208] |
Mon, 17 March 2008 23:56   |
wfzhao
Messages: 11
Registered: March 2008
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Junior Member |
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On 3月18日, 上午6时31分, "mgal...@gmail.com" <mgal...@gmail.com> wrote:
> On Mar 17, 3:52 pm, mankoff <mank...@gmail.com> wrote:
>
>
>
>
>
>> 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
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>>>> > > PRO STREAMLINE_DEMO
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>>>> > > 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)
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>>>> > > VEL, u, v, NVECS = 100, NSTEPS = 100, length = 0.5
>
>>>> > > END
>
>>>> > Following on from Ken's example, you might also try,
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>>>> > 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.
>
> Yes, all six images are from the same data. And yes, I think the
> standard grid of vectors is not very useful.
>
> Mike
> --www.michaelgalloy.com
> Tech-X Corporation
> Software Developer II- 隐藏被引用文字 -
>
> - 显示引用的文字 -
thanks for you response.
I think OSTR and GSTR are what I need.
and I download the source code from your web site named mg_lic.pro and
run in IDL, but it causes my cpu 100% and my computer crash down. so
may I use it correctly or I can adjust some parameter to decrease the
data?
for the first gird, I already do it successfully on the countour
plot, which means to overplot wind grid arrow on the contour plot map.
wenfang
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