| Re: surface plotting [message #37630] |
Wed, 14 January 2004 09:21 |
Norbert Hahn
Messages: 46
Registered: May 2003
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Member |
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Muks Raju <mpraju@harvest.eecs.umich.edu> wrote:
> Hello
> Yes you are right. I would like to picture the sphere as the earth
> and then project the colors which rep the diff densities on that earth. I
> guess I understand the concept but my data is in such a wierd form.
> I have a vector X = [X1,X2,X3.....X4880] and Y = [y1,y2,..y4880] and
> Z=[Z1,z2..z4880] and data=[d1,d2...d4880].. with the data in this format
> how do i do the said transformation? Any help would be much appreciated.
The transformation requires more than one step. CV_COORD will convert your
coordinates contained in x,y,z to longitude, latitude (and radius).
sph_coord = CV_COORD ( FROM_RECT=[x,y,z], /TO_SPHERE )
The longitude is contained in sph_coord (0,*), the latitude is in
sph_coord(1,*). The radius will not be used for map projections.
Ideally sph_coord(2,*) should contain the same values.
Next use MAP_SET to establish the map projection you want to use. Calling
MAP_SET without any parameters will establish a default projection. After
that IDL assumes all coordinates following are longitude, latitude and data.
CONTOUR will plot your data. The keyword IRREGULAR should be set. You may
need to read the online help for each routine you call.
Norbert
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| Re: surface plotting [message #37644 is a reply to message #37630] |
Tue, 13 January 2004 12:41  |
Muks Raju
Messages: 6
Registered: April 2002
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Junior Member |
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Hello
Yes you are right. I would like to picture the sphere as the earth
and then project the colors which rep the diff densities on that earth. I
guess I understand the concept but my data is in such a wierd form.
I have a vector X = [X1,X2,X3.....X4880] and Y = [y1,y2,..y4880] and
Z=[Z1,z2..z4880] and data=[d1,d2...d4880].. with the data in this format
how do i do the said transformation? Any help would be much appreciated.
Muks
On
Tue, 13 Jan 2004, Norbert Hahn wrote:
> "Muks Raju" <muks@ieee.org> wrote:
>
>> Hello
>> Im stuck with a problem.. i have 3 vectors containing 5000 values
>> of X,Y and Z coordinates of points on a sphere.
>
> What kind of projection do you think of? You may select one of the
> map projections or picture the sphere as a ball using a light source.
>
>> Now I also have data which
>> signifies the density at each of those points. How do i plot this data on
>> a sphere with different colors for diff densities and interpolate the
>> values to get a smooth color distribution.
>
> You may think of your sphere as of the earth without continents and
> oceans and project the colors that represent the diff densities on
> that "earth". Is that a way you may want to go?
>
> Map projections are standard transformations in IDL, so nothing to
> worry about.
>
> Norbert
>
>
--
Que Sera! Sera!..What will be, will be!
------------------------------------------------------------ ----------------
#### #### Mukunda P Raju
#### #### Graduate Student,
######### Systems Engineering, EECS
### # ### University of Michigan, Ann Arbor
#### #### United States of America
------------------------------------------------------------ ----------------
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| Re: surface plotting [message #37649 is a reply to message #37644] |
Tue, 13 January 2004 07:47 |
Norbert Hahn
Messages: 46
Registered: May 2003
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Member |
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"Muks Raju" <muks@ieee.org> wrote:
> Hello
> Im stuck with a problem.. i have 3 vectors containing 5000 values
> of X,Y and Z coordinates of points on a sphere.
What kind of projection do you think of? You may select one of the
map projections or picture the sphere as a ball using a light source.
> Now I also have data which
> signifies the density at each of those points. How do i plot this data on
> a sphere with different colors for diff densities and interpolate the
> values to get a smooth color distribution.
You may think of your sphere as of the earth without continents and
oceans and project the colors that represent the diff densities on
that "earth". Is that a way you may want to go?
Map projections are standard transformations in IDL, so nothing to
worry about.
Norbert
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