Re: [Matplotlib-users] Plot vs Line Collections

[Andrea G. <and...@gm...>]

Hi John,

On 5/31/07, John Hunter wrote:
> On 5/31/07, Andrea Gavana <and...@gm...> wrote:
> > Hi All,
> >
> >     I am writing an application (wxPython based) which embeds a big
> > matplotlib figure as a main panel. Basically, this app shows oil well
> > producers and gas injectors on a 2D map as dots (every dot represents
> > its surface location), and a bunch of "streamlines" (i.e., straight
> > lines or simple curves) which connect injectors and producers.
> > As the numerical simulation continues, more and more streamlines are
> > added to the plot (because of new wells or because interference
> > between wells), and actually I end up having 200 dots plus 800-1200
> > lines. As the simulation progresses, the plots become slower and
> > slower...
> > As the lines are usually 2-points straight lines, I was thinking about
> > using Line Collections; however, every matplotlib line has a linewidth
> > value that is dependent on the calculated "interference" effect
> > between wells, which means I have to build a matplotlib line for every
> > line connecting an injector with a producer. Moreover, every injector
> > well has its own colour for the streamlines (there are 33 injector
> > wells).
> > Will Line Collections save some time in this case? If not, does anyone
> > have a suggestion on how I could try to speed-up the plotting? I am
> > not really familiar with some obscure line/axes properties, so I may
> > have overlooked something.
>
> Yes, a line collection will save you a lot of time with upwards of
> 1000 line segments.  This is the use case they were designed to solve:
> a bunch of segments of differing widths and colors.  One could
> optimize it for the special case of simple line segments, ie [(x1,y1),
> (x2, y2)] in which case we could use numpy arrays, but currently we
> have only the general case of a collection of arbitrary length
> segments, and since they are not necessarily the same length, we use a
> sequence of segments rather than an array, and this is slower than it
> could be.

Thank you for your answer. I am going to try to build these line
collections and see what I can get. I never used them before so it's
like I will get something not very well performing at first...

Thank you for your answer, I am going to look at some examples...

Andrea.

"Imagination Is The Only Weapon In The War Against Reality."
http://xoomer.virgilio.it/infinity77/