Re: [Matplotlib-users] plotting an array of enumerated values
By the way, I had some success with this, but my approach is really
inefficient. Perhaps someone could suggest how I can improve the following:
import matplotlib.numerix as nx
from numarray import ma
def enumimage(A,colors):
Create an image from a matrix of enumerated values
A is a matrix
colors is a dictionary mapping enumerated values to (r,g,b,a) tuples
If a value in A is masked, the resulting image will be transparent
If a value in A is not present in the color map, it will plot black.
B = nx.zeros((nx.size(A,0),nx.size(A,1),4))
mask = A.mask()
for r in range(nx.size(A,0)):
for c in range(nx.size(A,1)):
v = A[r,c]
if mask[r,c]:
B[r,c,:]=[1,1,1,0]
else:
try:
B[r,c,:]=colors[v]
except KeyError,e:
B[r,c,:]=[0,0,0,1]
return B
if __name__=='__main__':
import pylab
A = nx.array([[1,2,7],[1,2,2],[1,1,9]])
print A =,A
A1 = ma.array(A,mask=ma.where(A==1,1,0))
print A1 =,A1
colors={
2:(1,0,0,1)
,7:(0,1,0,1)
}
B = enumimage(A1,colors)
print B =,B
pylab.figure()
pylab.hold()
pylab.imshow(B,interpolation='nearest',extent=0.5+nx.array([0,nx.size(A,0),nx.size(A,1),0]))
pylab.axes
pylab.show()
John Pye wrote:
Hi all
I have some data with enumerated values in an array. Values are like
1,2,7,9 spread around in the array. I want to plot those values so that
I can see the 'regions' in my data, then I want to overlay this with
some contour lines drawn from other data.
I want to be able to specify the colors for each of the enumerated
values, as they need to be consistent throughout my work. My array of
enumerated values is *masked* so that there are areas where I don't want
to show anything (this would plot as transparent pixels).
Has anyone got suggestions on the best way of doing this? It seems that
the technique in
http://www.scipy.org/Cookbook/Matplotlib/Plotting_Images_with_Special_Values
might be overkill, right? It also seemed that it had some problems with
masked arrays.
Cheers
JP
--
John Pye
School of Mechanical and Manufacturing Engineering
The University of New South Wales
Sydney NSW 2052 Australia
t +61 2 9385 5127
f +61 2 9663 1222
mailto:john.pye_AT_student_DOT_unsw.edu.au
http://pye.dyndns.org/
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Re: [Matplotlib-users] latex labels on plots
Hi,
frac works for me:
yaxislabel=r'\sffamily water content $\left(
\frac{\textsf{kg}}{\textsf{m}^{\textsf{\small 2}}}\right) $'
ylabel(yaxislabel)
And you can also set
rc('text', usetex=False)
in your file to enable or disable tex
in my case I did the following:
tex_out=True # False
if tex_out:
xaxislabel=r'time ($\sqrt{\textsf{s}}$)'
yaxislabel=r'\sffamily water content $\left(
\frac{\textsf{kg}}{\textsf{m}^{\textsf{\small 2}}}\right) $'
rc('text', usetex=True)
else:
xaxislabel='time (s**0.5)'
yaxislabel='water content (kg/m2)'
rc('text', usetex=False)
It's perhaps not the mose elegant way to do, but I'm quite new to
python/pylab/matplotlib
Wolfgang
John Pye schrieb:
Hi all
I came across this page: http://www.scipy.org/Cookbook/Matplotlib/UsingTex
which mentions using LaTeX to generate labels on plots in Matplotlib.
What I only discovered recently is that you don't need this 'usetext=1'
thing in order to create captions on plots that include subscripts, etc.
According to section 2.6.4 of the user's guide, you can just surround
your text with $...$ to have it formatted as if it were latex. This is
especially important if you're exporting SVG graphics (eg if you want to
add more captioning/labelling using inkscape): the 'usetex' approach
fails in that case.
I wonder if someone with write access to the scipy wiki could maybe
update the above page with some comments about the 'mathtext' support in
Matplotlib? It might also be worth noting that the mathtext
functionality doesn't support the \frac operator.
Cheers
JP
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Re: [Matplotlib-users] exponent fonts with usetex
It seems like no one has any comments on our plans concerning the
exponent fonts. Can you outline for me what it would take to fix
this? If it is fairly simple I may take a crack at it.
Ryan
On 6/14/06, Darren Dale [EMAIL PROTECTED] wrote:
I agree that this little experiment of trying to work around latex's
limitations has been too much trouble. I suggest we go back to the old
behavior, and anyone who wants sans-serif fonts in their exponents can use
regular mathtext. I'm hopeful that Edin can make some strides with mpl's
mathtext support, and in the meantime, people should get decent results if
they set ps.useafm : True in their rc settings.
Comments?
On Wednesday 14 June 2006 19:53, Ryan Krauss wrote:
(Sorry, I submitted this email with a real figure instead of a toy
example and the file size was too big and it awaits moderator
approval).
I am afraid I asked you to open a can of worms and now I don't know
what we should do. With my font size settings, \small looks to small
for the exponents. I tried \normalsize and actually got decent
results with \large (replacing all occurances of \small in your
ticker.py). See that attached file. But if \small looked good with
your settings, I am afraid things are now dependent on the font
settings in the rc file as far as what should go in the latex command
for the exponents.
I remember that this problem came up because I complained about serif
fonts in my exponents and we were having a hard time making tex use
sans serif math fonts.
Maybe the best solution is for me to go back in time and retract that
complaint.
I don't know. Sorry about the mess this had made. I have plots I am
fairly happy with (I will poke around in my rc file and see if I can
find out why my x and y axis fonts look different).
Ryan
On 6/14/06, Ryan Krauss [EMAIL PROTECTED] wrote:
I am afraid I asked you to open a can of worms and now I don't know
what we should do. With my font size settings, \small looks to small
for the exponents. I tried \normalsize and actually got decent
results with \large (replacing all occurances of \small in your
ticker.py). See that attached file. But if \small looked good with
your settings, I am afraid things are now dependent on the font
settings in the rc file as far as what should go in the latex command
for the exponents.
I remember that this problem came up because I complained about serif
fonts in my exponents and we were having a hard time making tex use
sans serif math fonts.
Maybe the best solution is for me to go back in time and retract that
complaint.
I don't know. Sorry about the mess this had made. I have plots I am
fairly happy with (I will poke around in my rc file and see if I can
find out why my x and y axis fonts look different).
Ryan
On 6/14/06, Ryan Krauss [EMAIL PROTECTED] wrote:
I feel bad that I caused this problem and am now asking you to fix it.
Ryan
On 6/14/06, Darren Dale [EMAIL PROTECTED] wrote:
This is an artifact that was introduced when I tried to give you
support for sans-serif fonts in the exponent. Try the attached
ticker.py, it wraps the exponent in {\small}. Let me know if this is
acceptable, and I'll commit it.
On Wednesday 14 June 2006 19:14, Ryan Krauss wrote:
I still have the problem with large exponents with your
matplotlibrc file (but the y-axis plots are no longer different).
Any thoughts on what I should try next?
Ryan
On 6/14/06, Darren Dale [EMAIL PROTECTED] wrote:
On Wednesday 14 June 2006 18:51, you wrote:
There was a lot of stuff in my tex.cache, but deleting didn't
solve my problem.
I may have some strange choices for my fonts and font sizes.
Can you send me a copy of your matplotlibrc file.
Ryan
On 6/14/06, Darren Dale [EMAIL PROTECTED] wrote:
Hi Ryan,
I'm using the latest svn as well (2479), and I cant reproduce
your problem. Try deleting your tex.cache.
Darren
On Wednesday 14 June 2006 18:14, Ryan Krauss wrote:
I am having a problem with the fonts for exponents on
semilog plots with usetex.
The attached figure can be generated on my machine with
figure(1)
t=arange(0,10,0.01)
y=sin(2*pi*t)
semilogx(t,y)
I just upgraded to the latest svn and now the y-axis plots
look different from the x-axis.
matplotlib.__version__
Out[6]: '0.87.3'
Ryan
--
Darren S. Dale, Ph.D.
Cornell High Energy Synchrotron Source
Cornell University
200L Wilson Lab
Rt. 366 Pine Tree Road
Ithaca, NY 14853
