Re: [Matplotlib-users] 2D Radial Plots
It sounds to me that you want to have a contour plot which takes as input
the r,theta, and T. I would suggest just
On 6/26/07, Lorenzo Isella [EMAIL PROTECTED] wrote:
Hello,
Thanks for your suggestion, but I still have a problem.
Maybe I did not make myself clear (or most likely I have a problem
about how to implement your suggestion): actually I have T=T(r,theta)
and I would like to make a 2D plot using colors such that one can see
that the domain where I am plotting is actually a circle.
The example I mentioned is not exactly what I need since there one can
find how to plot in polar coordinates a function of r alone.
Furthermore, I do not have necessarily an equally spaced grid.
For instance, let me consider the case of 5 theta's and 7 radial
position and consequentely 35 values of T:
theta R
T
0.00e+00 0.00e+00 5.459815003314423620e+01
0.00e+00 1.666574e-01 4.853828855239110851e+01
0.00e+00 3.333148e-01 4.315101251901344881e+01
0.00e+00 5.00e-01 3.836167151642037965e+01
0.00e+00 6.666297e-01 3.410390059527122020e+01
0.00e+00 8.332593e-01 3.031870066752165016e+01
0.00e+00 1.00e+00 2.695362096775039973e+01
1.570796326794896558e+00 0.00e+00 2.396203225329512776e+01
1.570796326794896558e+00 1.666574e-01 2.130248067207563523e+01
1.570796326794896558e+00 3.333148e-01 1.893811334477913277e+01
1.570796326794896558e+00 5.00e-01 1.683616770181326316e+01
1.570796326794896558e+00 6.666297e-01 1.496751749887080329e+01
1.570796326794896558e+00 8.332593e-01 1.330626922033307302e+01
1.570796326794896558e+00 1.00e+00 1.182940327795447999e+01
3.141592653589793116e+00 0.00e+00 1.051645503298913731e+01
3.141592653589793116e+00 1.666574e-01 9.349231221746512333e+00
3.141592653589793116e+00 3.333148e-01 8.311557855141172624e+00
3.141592653589793116e+00 5.00e-01 7.389056098930650407e+00
3.141592653589793116e+00 6.666297e-01 6.568943029058285532e+00
3.141592653589793116e+00 8.332593e-01 5.839854501207304871e+00
3.141592653589793116e+00 1.00e+00 5.191687680104649871e+00
4.712388980384689674e+00 0.00e+00 4.615461046534314882e+00
4.712388980384689674e+00 1.666574e-01 4.103189942205120566e+00
4.712388980384689674e+00 3.333148e-01 3.647775927922803252e+00
4.712388980384689674e+00 5.00e-01 3.242908421924544982e+00
4.712388980384689674e+00 6.666297e-01 2.882977255397825012e+00
4.712388980384689674e+00 8.332593e-01 2.562994933482758420e+00
4.712388980384689674e+00 1.00e+00 2.278527524544009530e+00
6.283185307179586232e+00 0.00e+00 2.025633220058637107e+00
6.283185307179586232e+00 1.666574e-01 1.800807713756398032e+00
6.283185307179586232e+00 3.333148e-01 1.600935643142084031e+00
6.283185307179586232e+00 5.00e-01 1.423247420534685892e+00
6.283185307179586232e+00 6.666297e-01 1.265280855439646635e+00
6.283185307179586232e+00 8.332593e-01 1.124847036463023642e+00
6.283185307179586232e+00 1.00e+00 1.00e+00
How would you plot them in order to have a 2D-color plot where one can
understand we are working on a circle (well, maybe it will look like
something different since I have only a few grid points, but the aim
is clear, I hope)?
Kind Regards
Lorenzo
On 26/06/07, Benoit Donnet [EMAIL PROTECTED] wrote:
Hey,
That's quite simple. Assume your file containing the data is name
Data.dat and is in the same directory than your python script.
from pylab import *
from numpy import *
tab = load('Data.dat') #load the file
r = tab[:,0] #get the r coordinates
theta = tab[:,1] #get the theta coordinates
T = tab[:,2] #get the temperature
# now, you can process/plot your data
Hope this help.
Best regards.
Benoit
Le 25-juin-07 à 19:03, Lorenzo Isella a écrit :
Dear All,
I am quite a newbie about Python and Pylab, but I am starting to like
the ease you can develop with using these tools.
I am interested in 2D radial plots (think for instance about the plot
of the temperature along the cross-section of a pipe).
I had a look at the tutorial online, in particular to the case
described in:
http://matplotlib.sourceforge.net/screenshots/polar_demo.py
but there is something which is not 100% clear to me.
What if, instead of having an analytical expression for the quantity I
want to plot I have to read it (together with the r and theta
coordinates) from a file, e.g.:
r theta T
where the columns r and theta contain the list
Re: [Matplotlib-users] 2D Radial Plots
Hello, Sorry for this tread getting quite long, but I am not getting there yet. Online I found examples like: #! /usr/bin/env python from pylab import * x=arange(-2,2,0.1) y=arange(-2,2,0.05) X,Y=meshgrid(x,y) z=exp(-(X*X + Y*Y)) + 0.6*exp(-((X+1.8)**2 + Y**2)) #contour(x,y,z,arange(0,1,0.1)) imshow(z,interpolation='nearest') show() and both the imshow() and contour() commands do nicely their job, but the scalar z is defined on a trivial rectangular domain and represented as a 2D array. In my problem I have: 1) a set of couples (theta,r) specifying a list of positions on a tube cross-section. 2) for each (theta,r) couple, I have a single value of T (which is thus a long 1D array). In general, (theta,r) may be two coordinates given on a non-trivial domain and I have a scalar specified for each couple I thus form. Both contour and imshow complain because they expect a 2D array. I am sorry if I am struggling over some triviality, but I am not making much progress by myself. Many thanks Lorenzo On 26/06/07, Brian [EMAIL PROTECTED] wrote: It sounds to me that you want to have a contour plot which takes as input the r,theta, and T. I would suggest just On 6/26/07, Lorenzo Isella [EMAIL PROTECTED] wrote: Hello, Thanks for your suggestion, but I still have a problem. Maybe I did not make myself clear (or most likely I have a problem about how to implement your suggestion): actually I have T=T(r,theta) and I would like to make a 2D plot using colors such that one can see that the domain where I am plotting is actually a circle. The example I mentioned is not exactly what I need since there one can find how to plot in polar coordinates a function of r alone. Furthermore, I do not have necessarily an equally spaced grid. For instance, let me consider the case of 5 theta's and 7 radial position and consequentely 35 values of T: theta R T 0.00e+00 0.00e+00 5.459815003314423620e+01 0.00e+00 1.666574e-01 4.853828855239110851e+01 0.00e+00 3.333148e-01 4.315101251901344881e+01 0.00e+00 5.00e-01 3.836167151642037965e+01 0.00e+00 6.666297e-01 3.410390059527122020e+01 0.00e+00 8.332593e-01 3.031870066752165016e+01 0.00e+00 1.00e+00 2.695362096775039973e+01 1.570796326794896558e+00 0.00e+00 2.396203225329512776e+01 1.570796326794896558e+00 1.666574e-01 2.130248067207563523e+01 1.570796326794896558e+00 3.333148e-01 1.893811334477913277e+01 1.570796326794896558e+00 5.00e-01 1.683616770181326316e+01 1.570796326794896558e+00 6.666297e-01 1.496751749887080329e+01 1.570796326794896558e+00 8.332593e-01 1.330626922033307302e+01 1.570796326794896558e+00 1.00e+00 1.182940327795447999e+01 3.141592653589793116e+00 0.00e+00 1.051645503298913731e+01 3.141592653589793116e+00 1.666574e-01 9.349231221746512333e+00 3.141592653589793116e+00 3.333148e-01 8.311557855141172624e+00 3.141592653589793116e+00 5.00e-01 7.389056098930650407e+00 3.141592653589793116e+00 6.666297e-01 6.568943029058285532e+00 3.141592653589793116e+00 8.332593e-01 5.839854501207304871e+00 3.141592653589793116e+00 1.00e+00 5.191687680104649871e+00 4.712388980384689674e+00 0.00e+00 4.615461046534314882e+00 4.712388980384689674e+00 1.666574e-01 4.103189942205120566e+00 4.712388980384689674e+00 3.333148e-01 3.647775927922803252e+00 4.712388980384689674e+00 5.00e-01 3.242908421924544982e+00 4.712388980384689674e+00 6.666297e-01 2.882977255397825012e+00 4.712388980384689674e+00 8.332593e-01 2.562994933482758420e+00 4.712388980384689674e+00 1.00e+00 2.278527524544009530e+00 6.283185307179586232e+00 0.00e+00 2.025633220058637107e+00 6.283185307179586232e+00 1.666574e-01 1.800807713756398032e+00 6.283185307179586232e+00 3.333148e-01 1.600935643142084031e+00 6.283185307179586232e+00 5.00e-01 1.423247420534685892e+00 6.283185307179586232e+00 6.666297e-01 1.265280855439646635e+00 6.283185307179586232e+00 8.332593e-01 1.124847036463023642e+00 6.283185307179586232e+00 1.00e+00 1.00e+00 How would you plot them in order to have a 2D-color plot where one can understand we are working on a circle (well, maybe it will look like something different since I have only a few grid points, but the aim is clear, I hope)? Kind Regards Lorenzo
Re: [Matplotlib-users] 2D Radial Plots
Can you convert your radial coordinates to Cartesian coordinates and use approach #2 here: http://scipy.org/Cookbook/Matplotlib/Gridding_irregularly_spaced_data Lorenzo Isella wrote: Hello, Sorry for this tread getting quite long, but I am not getting there yet. Online I found examples like: - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
[Matplotlib-users] 2D Radial Plots
Dear All, I am quite a newbie about Python and Pylab, but I am starting to like the ease you can develop with using these tools. I am interested in 2D radial plots (think for instance about the plot of the temperature along the cross-section of a pipe). I had a look at the tutorial online, in particular to the case described in: http://matplotlib.sourceforge.net/screenshots/polar_demo.py but there is something which is not 100% clear to me. What if, instead of having an analytical expression for the quantity I want to plot I have to read it (together with the r and theta coordinates) from a file, e.g.: r theta T where the columns r and theta contain the list of (r,theta) coordinates (the grid I am using along the cross section) and T the temperature evaluated at that grid point? If necessary, I can post an example file (but at the moment I am working with fairly big files and I think I conveyed an idea of what I am after). Many thanks Lorenzo - This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
