Hi John On Fri, Oct 13, 2006 at 03:42:13PM +0100, John Travers wrote:
Attached is a very simple script (will make it a test later) which uses the test data from netlib->dierckx to check the use fo regrid and surfit. The plot attached shows the results. There could be an error in my dealing with meshgrid (I hate they way it swaps axes), but I think it is right. The surfit part issues a warning on interpolation. If you increase s to say 20 (0 is needed for interpolation) then the warning goes, but then you are smoothing (as can be seen from the corresponding output plot - which was down sampled for file size).
I think matplotlib may be throwing a spanner in the wheels here by using its own interpolation. If you use imshow(x,interpolation='nearest') you get a plot like http://mentat.za.net/results/interpolate.png (I changed to a more densely sampled grid). As for the meshgrid behaviour, take a look at numpy's mgrid, which doesn't do the argument swapping.
I'll make this into a test at some point and also improve the interp2d interface to be more flexible to input array layout - but this will have to be nest week due to time constraints (I need to work...)
I'm sorry, I still havn't had time to merge the patch -- will hopefully be able to do that over the weekend at least.
Hope this demonstrates my point (and that yopu don't find an obvious error in my code...)
Thanks for the demo! Pretty pictures always make for a convincing argument. Cheers Stéfan