Thread: [Matplotlib-users] Annotation Finder Functor.

Hi,

I recently made an entry at the matplotlib cookbook wiki:

http://www.scipy.org/wikis/topical_software/InteractivePlotting

"""
I find it often quite useful to be able to identify points within a
plot simply by clicking. This recipe provides a fairly simple  functor
 that can be connected to any plot. I've used it with both scatter and
standard plots.
"""

I thought I'd post a note here soliciting for comments and suggestions
on how I might do this better and faster.  Specifically when the
number of points grows to tens of thousands things begin to crawl.  I
was wondering how I can refresh only the text markers rather than the
whole plot?  Also, is there a better way to identify the point closet
to where a user clicked?  axis.pick doesn't quite do the right thing
because it returns whole collections - right?

Thanks,   Chris

I would like to create an animation that shows the path of a vehicle  
moving
along a trajectory. The vehicle could be represented by a small  
circle with and arrow
pointing along the vehicle's current heading. It would be nice to  
leave a bread crumb trail
of the vehicles path as a line.

I found documentation on making animations and movies but plotting a  
sequence of plots.
But I am not sure how I create or plot the circle plus arrow and then  
move it for the next plot.
(unless I just replot the whole plot everyframe) The Animation  
cookbook apparently provides
some hints but I am a little lost as to where to begin.

Do I need to create an artist? or a cursor?
I am using WxAgg on Mac Os X 10.4.4 although I could use another OS X  
supported backend if
it would be easier than WXAgg.

Any hints or a get started example

Sam

On 06 Feb, 2006, at 12:34, Christopher Barker wrote:

> Samuel M. Smith wrote:
>> I would like to create an animation that shows the path of a  
>> vehicle moving
>> along a trajectory. The vehicle could be represented by a small  
>> circle with and arrow
>> pointing along the vehicle's current heading. It would be nice to  
>> leave a bread crumb trail
>> of the vehicles path as a line.
>
> Sam,
>
> This isn't a MPL solution, but as I notice you're using wxAgg, I  
> thought you might be interested in a wxPython solution. It would be  
> very easy to do this with wx.lib.floatcanvas. There is a demo for  
> it in the wxPython demo, and, if you want, I can send you the  
> latest version with a few more demos of it's capabilities.

Thanks for the suggestion. I haven't really used WxPython so there is  
a little bit of a learning curve and I was trying to get something
to work I had a presentation and not a lot of time.
I have installed the wxpython 2.6.2.1 demo distribution. Do you have  
more demos than what is in the distribution. If so I would appreciate  
getting them
as I would like to explore using wx python

I figured out a way to do it in Matplotlib. What I did is just draw  
lines and then use the line.set_data() method to update the position  
for each frame
My code is a little ugly and not the most speed efficient but I was  
able to generate the frames for movies. I used the "export slideshow  
to movie" command in GraphicConverter to convert the frames to a  
quicktime movie.
I couldn't really grok how transforms work so I couldn't move patches  
around.
The biggest problem is keeping the axis scaled which I never solved.  
I would have to play with the figure size.

I couldn't get real time animation to work, the screen never updates,  
but I could make movies.
Have you ever done an animation in WXAgg? When I run the example code  
from the cookbook, the screen doesn't update.
I think its broken on OS X.



Here is my code