extensive scatter plot

[Johannes Korn]

Hi,

I would like to produce a scatter plot with roughly 200 mio points.
Because the points are so numerous I rather need a point density plot.

I use numpy. Right now I loop over the individual data points and make a
where query on a meshgrid.

ind = where((x_grid == x_points[i]) & (y_grid == y_points[i]) )
counter_grid[ind] += 1

This is really slow. I'm sure there's a better solution already out there.

Kind regards!