Re: [Matplotlib-users] Scatter is slow to render many points

On Wed, Nov 19, 2008 at 8:56 AM, Gregory Desvignes
<Gre...@cn...> wrote:
>
> Hi all,
>
> I'm using matplotlib inside the backend_gtkagg with the scatter function
> to draw a simple graph with 20000 to 40000 points. The points may have
> only 2 differents sizes and 4 differents color depending on some criteria
> and should be 'clickable'.
>
> The problem is that the plot rendering is very slow when it deals with
> ~10000 points, especially if we compare it with the rendering of the plot
> function using simple points (as the "data_browser.py" example)
>
> Does anybody knows if there is a way to make things going a little
> bit faster?

"plot" with markers is *much* faster than scatter.  If you have only a
few different sizes and a few different colors, if you issue several
plot commands with one or more marker symbols

  plot(x1, y1, 'o', ms=10, color='red')
  plot(x2 y2, 's', ms=20, color='green')
  plot(x3, y3, '+', ms=8, color='blue')

It might be up to an order of magnitude faster.  And the individual
points will be selectable using the pick events, as described in

  http://matplotlib.sourceforge.net/users/event_handling.html

Hope this helps,
JDH