matplotlib-users Mailing List for matplotlib

Hi Jae-Joon,
Your simpler suggestion of drawing the fig twice is just fine for my 
needs. Thank you.
JL> The exact location of the legend is known at drawing time. Thus, the
JL> location of the text needs to be calculated at the drawing. I may
JL> help you with this but it is quite tricky and you need some
JL> knowledge on internals of the mpl.
JL>
JL> Or, you may simply draw the figure twice (with same renderer), where
JL> the first one is just to calculate the location of the text.
JL> Here is an example.
JL>
JL> ------------------
JL> import matplotlib.pyplot as plt
JL> plt.plot([1, 3, 2], label="test2")
JL> l = plt.legend()
JL> plt.draw() # the location of the legend is now known
JL>
JL> ax = gca()
JL> bbox = l.legendPatch.get_bbox().inverse_transformed(ax.transAxes) #
JL> bbox in axes coordinate.
JL> x = bbox.x0+bbox.width/2. # center
JL>
JL> ax.text(x, 0, "test", va="bottom", ha="center",
JL> transform=ax.transAxes) plt.draw()
JL> ---------------------
JL>
JL> Note that if you want save the figure, you need to save it with a
JL> same dpi, or save the figure twice as above.
JL>
JL> -JJ
-- 
Christopher Brown, Ph.D.
Department of Speech and Hearing Science
Arizona State University

James Boyle wrote:
> As far as I can tell, you cannot specify the color that contourf uses 
> for masked values.
> The examples enclosed with matplotlib ( 0.98.3) specifically comment 
> that this is the case.
> It appears that contourf just does not plot anything where the masked 
> values occur and the background ( usually white ) is what is seen.
> This is very useful but ....
> 
> I would like to have a bit more choice in how the areas of masked 
> data are represented.
> I came up with the following hack which seems to work, but being far 
> from expert I wanted to know if anyone wished to help or give advice.
> Is this reasonable or what ?
Jim,
It strikes me as the right way to do what you want; it is not a kludge 
or a hack at all. Contourf generates patches for unmasked regions, not 
for the masked region, so it is indeed up to you to set the background 
as you have done.
I see that there is also an Axes.set_axis_bgcolor method, which I would 
expect to be preferred; but it is strangely named. Should it not be 
just Axes.set_bg or Axes.set_bgcolor? It corresponds to the axisbg 
kwarg in the Axes initializer, perhaps another unfortunate choice of 
names.
(Contourf has a longstanding bug in handling internal masked regions; I 
hope you don't run into it. Both Mike D and I have tried to figure out 
how to fix that bug, but so far without success.)
> 
> In the code below data is a masked array with some areas masked.
> The result is that the missing areas are now black rather than white 
> ( the default background, I guess)
> 
> fig = pylab.figure()
> ax = fig.add_subplot(111)
> ax.axesPatch.set_facecolor('k')
> cs = ax.contourf(data)
> pylab.savefig('example')
> 
> I am aware that pcolor , pcolormesh and using cm.set_bad will work 
> but I also wanted the option for contourf - it produces nice looking 
> plots.
I have not checked just now, but as I recall, pcolor acts like contourf 
with respect to masked regions--it plots nothing there, leaving the 
background showing through.
Eric

As far as I can tell, you cannot specify the color that contourf uses 
for masked values.
The examples enclosed with matplotlib ( 0.98.3) specifically comment 
that this is the case.
It appears that contourf just does not plot anything where the masked 
values occur and the background ( usually white ) is what is seen.
This is very useful but ....
I would like to have a bit more choice in how the areas of masked 
data are represented.
I came up with the following hack which seems to work, but being far 
from expert I wanted to know if anyone wished to help or give advice.
Is this reasonable or what ?
In the code below data is a masked array with some areas masked.
The result is that the missing areas are now black rather than white 
( the default background, I guess)
fig = pylab.figure()
ax = fig.add_subplot(111)
ax.axesPatch.set_facecolor('k')
cs = ax.contourf(data)
pylab.savefig('example')
I am aware that pcolor , pcolormesh and using cm.set_bad will work 
but I also wanted the option for contourf - it produces nice looking 
plots.
Thanks for any help.
--Jim

Thanks Jeff! That is just wonderful! No need for a non-spherical earth
model for me.
Again, thanks!
Rob
Jeff Whitaker wrote:
> 
> Rob Frohne wrote:
>> Hi Jeff,
>>
>> I am an amateur radio operator, and I am writing a little application to
>> display where the major lobe of my antenna is pointing. I can control
>> the
>> direction of my antenna with the computer, and it would be nice to have a
>> display of the whole world, as well as circles representing how far the
>> station I am talking to is, and radial lines showing the bearings. I'd
>> like
>> to show the bearings along the edge of the map. For this type of map, a
>> circle is a much better boundary than a square, but if it has to be a
>> square, we should be able to make it a square bounding the circle, not
>> the
>> other way around. I think I can even plot the station's location given
>> data
>> I get from the Internet using this software. I am just learning Python,
>> but
>> it appears to be ideal for what I'm doing. 
>>
>> Right now I'm trying to figure out how to get the Eclipse IDE I am trying
>> out to show me the source code for Basemap. :-)
>>
>> Thanks for the expert help!
>>
>> Rob
>> 
> 
> Rob: I've updated basemap in SVN so that if neither a width/height or 
> corner lat/lons are provided, the whole world is plotted in a circle 
> with projection='aeqd'. If you can access SVN please try it out and let 
> me know how it works for you. If not, I can provide you with a tarball.
> 
> The full-disk aeqd will not work right now with ellipsoids, only for 
> perfect spheres. Is that a problem for you?
> 
> -Jeff
>> Jeff Whitaker wrote:
>> 
>>> Rob Frohne wrote:
>>> 
>>>> Hi,
>>>>
>>>> I think I am running into the same thing John is here. When you want
>>>> to
>>>> display the whole earth in 'aeqd' mode, the projection needs to be onto
>>>> a
>>>> circle. As it is, what is plotted is a square that just fits inside
>>>> the
>>>> circle I want. Here is a link to a photo of the kind of projection I
>>>> want.
>>>>
>>>> http://www.wm7d.net/az_proj/images/lon_anim_shaded.gif
>>>>
>>>> Is there a way to get the whole earth plotted with 'aeqd'?
>>>> 
>>>> 
>>> Rob: No, you can't get the whole earth - the most you can get is the 
>>> cube that fits within it. I can look into adding that functionality for 
>>> the aeqd projection if there's a real use case. Note that there are 
>>> other whole-earth projections available (mollweide, vandergrinten, 
>>> robinson, sinuisoidal etc). These projections have much less distortion 
>>> far away from the center of the map than the azimuthal equidistant 
>>> does. Why do you want to use aeqd to plot the whole globe?
>>>
>>> -Jeff
>>> 
>>>> Thanks,
>>>>
>>>> Rob
>>>> 
>>>> 
>>> 
>>>> John [H2O] wrote:
>>>> 
>>>> 
>>>>> Hello, 
>>>>>
>>>>> I'm creating a web application that will take user input from a
>>>>> javascript
>>>>> map to give me bounding coordinates (i.e. urcrnrlat, urcrnrlon,
>>>>> llcrnrlat,
>>>>> llcrnrlon) and possibly a switch for polar projection. Other than that
>>>>> I
>>>>> have no further information. Which projection is the most suitable to
>>>>> handle anything from a 'global' plot to a zoom say over a state? I
>>>>> don't
>>>>> see the zoom being too tight, but global projections are likely. I
>>>>> personally prefer Equal Area, hence right now I'm working with 'aeqd',
>>>>> but
>>>>> I seem to have problems if the plot is global with that projection.
>>>>>
>>>>> Just looking for advice, opinions, and ideally examples if anyone has
>>>>> created a similar function / module to use in a web environment.
>>>>>
>>>>> Thanks!
>>>>> -john
>>>>>
>>>>> 
>>>>> 
>>>> 
>>>> 
>>> -- 
>>> Jeffrey S. Whitaker Phone : (303)497-6313
>>> Meteorologist FAX : (303)497-6449
>>> NOAA/OAR/PSD R/PSD1 Email : Jef...@no...
>>> 325 Broadway Office : Skaggs Research Cntr 1D-113
>>> Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> _______________________________________________
>>> Matplotlib-users mailing list
>>> Mat...@li...
>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>>
>>>
>>> 
>>
>> 
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
> 
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Michael Droettboom <md...@st...>
writes:
> Passing solid_joinstyle='bevel' does resolve the problem on both 0.91.x 
> and 0.98.x. Additionally, path simplification (which is a new feature 
> on 0.98.x) also resolves this problem (set rcParam path.simplify to True).
It seems that agg and pdf have different ways to render small angles
when the join style is 'miter'. Pdf has a limit (settable in the pdf
file) beyond which it reverts to bevel-style angles, agg seems to always
do the miter join but cuts it off at some distance.
Here's a test script, and screenshots of (a part of) the agg and pdf
outputs when the join style is 'miter'.
-- 
Jouni K. Seppänen
http://www.iki.fi/jks

Rob Frohne wrote:
> Hi Jeff,
>
> I am an amateur radio operator, and I am writing a little application to
> display where the major lobe of my antenna is pointing. I can control the
> direction of my antenna with the computer, and it would be nice to have a
> display of the whole world, as well as circles representing how far the
> station I am talking to is, and radial lines showing the bearings. I'd like
> to show the bearings along the edge of the map. For this type of map, a
> circle is a much better boundary than a square, but if it has to be a
> square, we should be able to make it a square bounding the circle, not the
> other way around. I think I can even plot the station's location given data
> I get from the Internet using this software. I am just learning Python, but
> it appears to be ideal for what I'm doing. 
>
> Right now I'm trying to figure out how to get the Eclipse IDE I am trying
> out to show me the source code for Basemap. :-)
>
> Thanks for the expert help!
>
> Rob
> 
Rob: I've updated basemap in SVN so that if neither a width/height or 
corner lat/lons are provided, the whole world is plotted in a circle 
with projection='aeqd'. If you can access SVN please try it out and let 
me know how it works for you. If not, I can provide you with a tarball.
The full-disk aeqd will not work right now with ellipsoids, only for 
perfect spheres. Is that a problem for you?
-Jeff
> Jeff Whitaker wrote:
> 
>> Rob Frohne wrote:
>> 
>>> Hi,
>>>
>>> I think I am running into the same thing John is here. When you want to
>>> display the whole earth in 'aeqd' mode, the projection needs to be onto a
>>> circle. As it is, what is plotted is a square that just fits inside the
>>> circle I want. Here is a link to a photo of the kind of projection I
>>> want.
>>>
>>> http://www.wm7d.net/az_proj/images/lon_anim_shaded.gif
>>>
>>> Is there a way to get the whole earth plotted with 'aeqd'?
>>> 
>>> 
>> Rob: No, you can't get the whole earth - the most you can get is the 
>> cube that fits within it. I can look into adding that functionality for 
>> the aeqd projection if there's a real use case. Note that there are 
>> other whole-earth projections available (mollweide, vandergrinten, 
>> robinson, sinuisoidal etc). These projections have much less distortion 
>> far away from the center of the map than the azimuthal equidistant 
>> does. Why do you want to use aeqd to plot the whole globe?
>>
>> -Jeff
>> 
>>> Thanks,
>>>
>>> Rob
>>> 
>>> 
>> 
>>> John [H2O] wrote:
>>> 
>>> 
>>>> Hello, 
>>>>
>>>> I'm creating a web application that will take user input from a
>>>> javascript
>>>> map to give me bounding coordinates (i.e. urcrnrlat, urcrnrlon,
>>>> llcrnrlat,
>>>> llcrnrlon) and possibly a switch for polar projection. Other than that I
>>>> have no further information. Which projection is the most suitable to
>>>> handle anything from a 'global' plot to a zoom say over a state? I don't
>>>> see the zoom being too tight, but global projections are likely. I
>>>> personally prefer Equal Area, hence right now I'm working with 'aeqd',
>>>> but
>>>> I seem to have problems if the plot is global with that projection.
>>>>
>>>> Just looking for advice, opinions, and ideally examples if anyone has
>>>> created a similar function / module to use in a web environment.
>>>>
>>>> Thanks!
>>>> -john
>>>>
>>>> 
>>>> 
>>> 
>>> 
>> -- 
>> Jeffrey S. Whitaker Phone : (303)497-6313
>> Meteorologist FAX : (303)497-6449
>> NOAA/OAR/PSD R/PSD1 Email : Jef...@no...
>> 325 Broadway Office : Skaggs Research Cntr 1D-113
>> Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
>>
>>
>> ------------------------------------------------------------------------------
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>>
>> 
>
> 

Dear ALL,
Could you please someone test the attached Python code (of my map
displaying test program written with MPL/Basemap/wxPython) under
MS-Windows and send me a screenshot? I have received reports saying
that the map does not fill the entire figure under MS-Windows;
however, under Ubuntu Linux it appears correctly. I have included a
conditional test before creating the figure when running under
MS-Windows to create a figure twice the size of that created under
Linux.
Thanks in advance!
With warmest regards, and Happy New Year!
-- 
Dr. Mauro J. Cavalcanti
Ecoinformatics Studio
P.O. Box 46521, CEP 20551-970
Rio de Janeiro, RJ, BRASIL
E-mail: mau...@gm...
Web: http://studio.infobio.net
Linux Registered User #473524 * Ubuntu User #22717
"Life is complex. It consists of real and imaginary parts."

The exact location of the legend is known at drawing time. Thus, the
location of the text needs to be calculated at the drawing. I may help
you with this but it is quite tricky and you need some knowledge on
internals of the mpl.
Or, you may simply draw the figure twice (with same renderer), where
the first one is just to calculate the location of the text.
Here is an example.
------------------
import matplotlib.pyplot as plt
plt.plot([1, 3, 2], label="test2")
l = plt.legend()
plt.draw() # the location of the legend is now known
ax = gca()
bbox = l.legendPatch.get_bbox().inverse_transformed(ax.transAxes) #
bbox in axes coordinate.
x = bbox.x0+bbox.width/2. # center
ax.text(x, 0, "test", va="bottom", ha="center", transform=ax.transAxes)
plt.draw()
---------------------
Note that if you want save the figure, you need to save it with a same
dpi, or save the figure twice as above.
-JJ
On Tue, Dec 30, 2008 at 5:16 PM, Christopher Brown <c-...@as...> wrote:
> Hi,
>
> How can I get the position, in x coordinates/units, of the legend?
> Specifically, I'd like to get the center of the legend box, because I
> want to add some text that is centered-aligned with the legend. Thanks.
>
> --
> Christopher Brown, Ph.D.
> Department of Speech and Hearing Science
> Arizona State University
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Please feel free to do so. If you need anything from me, I will be glad to
provide it.
dave
John Hunter-4 wrote:
> 
> On Tue, Dec 30, 2008 at 1:31 PM, davev <dv...@li...> wrote:
>>
>> Thank you John, that made the difference. I had read that you needed to
>> call
>> the draw function for the canvas first but it wasn't clear from the
>> examples. Now that you have given me the correct place to make the call,
>> things are working as expected.
>>
>> If we wanted to, this small project could easily be turned into an
>> additional example for the animation example code so that others could
>> potentially benefit from it as well. If you think that is a good idea,
>> let
>> me know and I'll look at making it happen. At the very least, the final
>> version of the files could be posted so that others could easily
>> view/download the files as example code. I would include the wxGlade file
>> so
>> that there would also be an example of that available as well.
> 
> Sure, that sounds great. I think the example with the start and stop
> buttons would be nice, as would the wxglade part. I can add them to
> the animations examples dir.
> 
> JDH
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
> 
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Hi Jeff,
I am an amateur radio operator, and I am writing a little application to
display where the major lobe of my antenna is pointing. I can control the
direction of my antenna with the computer, and it would be nice to have a
display of the whole world, as well as circles representing how far the
station I am talking to is, and radial lines showing the bearings. I'd like
to show the bearings along the edge of the map. For this type of map, a
circle is a much better boundary than a square, but if it has to be a
square, we should be able to make it a square bounding the circle, not the
other way around. I think I can even plot the station's location given data
I get from the Internet using this software. I am just learning Python, but
it appears to be ideal for what I'm doing. 
Right now I'm trying to figure out how to get the Eclipse IDE I am trying
out to show me the source code for Basemap. :-)
Thanks for the expert help!
Rob
Jeff Whitaker wrote:
> 
> Rob Frohne wrote:
>> Hi,
>>
>> I think I am running into the same thing John is here. When you want to
>> display the whole earth in 'aeqd' mode, the projection needs to be onto a
>> circle. As it is, what is plotted is a square that just fits inside the
>> circle I want. Here is a link to a photo of the kind of projection I
>> want.
>>
>> http://www.wm7d.net/az_proj/images/lon_anim_shaded.gif
>>
>> Is there a way to get the whole earth plotted with 'aeqd'?
>> 
> 
> Rob: No, you can't get the whole earth - the most you can get is the 
> cube that fits within it. I can look into adding that functionality for 
> the aeqd projection if there's a real use case. Note that there are 
> other whole-earth projections available (mollweide, vandergrinten, 
> robinson, sinuisoidal etc). These projections have much less distortion 
> far away from the center of the map than the azimuthal equidistant 
> does. Why do you want to use aeqd to plot the whole globe?
> 
> -Jeff
>> Thanks,
>>
>> Rob
>> 
> 
> 
>>
>> John [H2O] wrote:
>> 
>>> Hello, 
>>>
>>> I'm creating a web application that will take user input from a
>>> javascript
>>> map to give me bounding coordinates (i.e. urcrnrlat, urcrnrlon,
>>> llcrnrlat,
>>> llcrnrlon) and possibly a switch for polar projection. Other than that I
>>> have no further information. Which projection is the most suitable to
>>> handle anything from a 'global' plot to a zoom say over a state? I don't
>>> see the zoom being too tight, but global projections are likely. I
>>> personally prefer Equal Area, hence right now I'm working with 'aeqd',
>>> but
>>> I seem to have problems if the plot is global with that projection.
>>>
>>> Just looking for advice, opinions, and ideally examples if anyone has
>>> created a similar function / module to use in a web environment.
>>>
>>> Thanks!
>>> -john
>>>
>>> 
>>
>> 
> 
> 
> -- 
> Jeffrey S. Whitaker Phone : (303)497-6313
> Meteorologist FAX : (303)497-6449
> NOAA/OAR/PSD R/PSD1 Email : Jef...@no...
> 325 Broadway Office : Skaggs Research Cntr 1D-113
> Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
> 
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