matplotlib-users Mailing List for matplotlib

On 2/26/12 6:42 AM, David Craig wrote:
> Hi, I recently installed basemap and python imaging library on my 
> laptop. I have an i686 machine with fedora 16 on it. I just tried some 
> test plots and basemap seems to work fine but according to the 
> documentation to use the bluemarble(), etopo(), shadedrelief() and 
> warpimage() instance methods I need PIL. SO I installed it via yum,
>
> $ sudo yum install python-imaging.i686
>
> however only the bluemarble method works. If I try any of the others I 
> get the following error.
>
> AttributeError                            Traceback (most recent call 
> last)
> /usr/lib/python2.7/site-packages/IPython/utils/py3compat.pyc in 
> execfile(fname, *where)
>     173             else:
>     174                 filename = fname
> --> 175             __builtin__.execfile(filename, *where)
>
> /home/davcra/Desktop/python_scripts/blue_marble.py in <module>()
>      10
>      11
> ---> 12 m.shadedrelief()
>      13 plt.show()
>
> AttributeError: 'Basemap' object has no attribute 'shadedrelief'
>
> Anyone know what I did wrong????
> Thanks
> David
>
David:  You must not have the latest version of Basemap installed, the 
shadedrelief method was added in 1.0.2.

-Jeff

Hi, I recently installed basemap and python imaging library on my laptop. I
have an i686 machine with fedora 16 on it. I just tried some test plots and
basemap seems to work fine but according to the documentation to use the
bluemarble(), etopo(), shadedrelief() and warpimage() instance methods I
need PIL. SO I installed it via yum,

$ sudo yum install python-imaging.i686

however only the bluemarble method works. If I try any of the others I get
the following error.

AttributeError                            Traceback (most recent call last)
/usr/lib/python2.7/site-packages/IPython/utils/py3compat.pyc in
execfile(fname, *where)
    173             else:
    174                 filename = fname
--> 175             __builtin__.execfile(filename, *where)

/home/davcra/Desktop/python_scripts/blue_marble.py in <module>()
     10
     11
---> 12 m.shadedrelief()
     13 plt.show()

AttributeError: 'Basemap' object has no attribute 'shadedrelief'

Anyone know what I did wrong????
Thanks
David

On 02/26/12 06:25, Eric Firing wrote:
> On 02/25/2012 03:54 AM, Alejandro Dubrovsky wrote:
>> Hi,
>>
>> I've run into something that I expect to be ground well covered but I
>> can't find anything relevant on google.
>>
>> I'm on linux. When using the GtkAgg backend on matplotlib 1.1.0 (or git
>> head for that matter), with interactive mode on, one call to draw() only
>> gives me a blank window, while a second draw() immediately afterwards
>> will draw the requested graph. On IRC, askewchan told me it only one
>> draw is required under MacOSX, and it also works fine with just one draw
>> call if I switch to the TkAgg backend.
> 
> This does not have a simple answer.  The basic problem is a collision 
> between event-driven programming (the gui toolkit) and nice, simple 
> sequential programming such as in your script.  The plotting commands 
> essentially register requests with the gui toolkit, and the toolkit 
> executes them when it gets around to it.  It won't do it during a 
> time.sleep().  Typically, it has to be waiting for input, because that 
> is when the mainloop is checking to see if there is anything that needs 
> to be done.
> 
Ah, good explanation.

>>
>> The following short script should demonstrate the issue (note: this is
>> only a problem when run as a script. It works fine on ipython, or
>> standard python prompt):
>>
> 
> Try removing *all* your "draw" commands, and replace the calls to 
> time.sleep(2) with plt.pause(2).  That works for me on gtkagg, qt4agg, 
> wxagg, and tkagg. plt.pause() calls the event loop while waiting, 
> instead of just freezing everything like sleep() does.
> 
Yes, that works here too. It works even in non-interactive mode. Thank you.

I tried replacing all the draws in my program with plt.pause(0.01), and
it worked fine on GtkAgg, but when I tried it in QtAgg, it went to blank
screen mode. But upping it to 0.05 worked on both. So I went trawling
through code.

pause, through some intermediaries, seems to call flush_events, which
does the interfacing to the corresponding toolkit telling it to process
events, and then calls time.sleep for 0.01 seconds.  It does this until
the total slept time matches or exceeds what you specify.  And it seems
that Qt needs two separate rounds to get everything done. So a call like
plt.pause(0.015) works well

The time.sleep calls from pause seem unnecessary for the people like me
that just want to use pause as a get events processed signals.  It would
be good if flush_events had a direct interface.

(writing this so that maybe it gets picked up by a search engine)

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