Velocity vectors on maps

Velocity vectors on maps

Post by Kenneth P. Bowm » Thu, 07 Oct 1999 04:00:00



Can anyone give me pointers to IDL procedures to making correct velocity
vector plots on maps, notably azimuthal polar projections?

This is one of those annoying inadequacies in IDL (see earlier discussion
on mathematical routines) that include niggling mapping and contouring
problems.  (NCAR graphics did vector and streamline plots well years ago
-- if you could stand to use NCAR graphics.)

Thanks, Ken Bowman

--
Dr. Kenneth P. Bowman, Professor                409-862-4060
Department of Meteorology                       409-862-4466 fax
Texas A&M University                            bowmanATcsrp.tamu.edu

 
 
 

Velocity vectors on maps

Post by w.. » Fri, 08 Oct 1999 04:00:00



Quote:>Can anyone give me pointers to IDL procedures to making correct velocity
>vector plots on maps, notably azimuthal polar projections?

This is a code fragment:

  fx1=fx*cosd(lo)+fy*sind(lo)
  fy1=-fx*sind(lo)+fy*cosd(lo)

which works OK for polar stereo... [fx,fy] are the original arrow sizes,
lo the longitudes at the arrow positions, and [fx1,fy1] the rotated arrows.

-W.

--

Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself

 
 
 

Velocity vectors on maps

Post by Martin.Schu.. » Sat, 09 Oct 1999 04:00:00





>>Can anyone give me pointers to IDL procedures to making correct velocity
>>vector plots on maps, notably azimuthal polar projections?

You may want to take a look at my improved VELOVECT routine. It will *not*
plot vectors in the correct length probably, but at least it works with
any map projection and with irregularily gridded data, so it could be a
place to start.

Please find msvelovect.pro attached.

--
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[
[[     Martin Schultz   Max-Planck-Institut fuer Meteorologie    [[
[[                      Bundesstr. 55, 20146 Hamburg             [[
[[                      phone: +49 40 41173-308                  [[
[[                      fax:   +49 40 441787                     [[

[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[

  msvelovect.pro
8K Download
 
 
 

1. Velocity vectors on map

Hi folks,

Does anyone have a code to plot wind vectors correctly on a map
(azimuthal polar projection)?  
The vector length should not plotted with respect to a cell (In the
procedure "VELOVECT", the vector length is with respect to a cell) ..
If you have any idea about this, please reply for me.
Thanks,

Kyong Seo
---------------------------------------------------------        
Texas A&M University         Office:(409) 845-0189      

2. XSLT - XPATH - Expression

3. Plotting Velocity Vectors - More Help

4. COMM problem??????

5. Plotting Velocity Vectors- Help Required

6. Copy of Outgoing Messages

7. Need a vector map for a CD 4029

8. Problems using project central on the web

9. Boomkark Automatically - Vector Map File

10. Vector maps set to output res of 300

11. Vector mapping in IDL

12. IDL to Java Mapping for Java Vectors a User Defined Classes

13. wind vectors & map