Jeff, Nevermind... I figured out the problem... It appears that the grads mpl interface (pygrads) wasn't creating an appropriate mask for the data. All of the '-9.99e+8' values that correspond to 'undefined' points weren't being masked out, and were thus causing quiver to freak out & try to draw some extreme vector arrows...
I fixed the mask, and it works fine now... Sorry for the bother, but thanks anyway for the help... Regards, P.R. -----Original Message----- From: Jeff Whitaker [mailto:jsw...@fastmail.fm] Sent: 2009-08-11 11:05 PM To: P.R. Cc: matplotlib-users@lists.sourceforge.net Subject: Re: [Matplotlib-users] problem with basemap/quiver with latest versions of basemap&mpl P.R. wrote: > Ok, I upgraded to numpy 1.30 and the problem still showed up... > Im still getting those strange diagonal line defects. > (looks as if some of the edge arrow polygons are being clipped/drawn/closed > improperly & thus 'dragged' across the plot area???) > > I attached my x,y,u,v arrays... > P.R. The file appears to be corrupted: In [4]: from numpy import load In [5]: load('xy_uv.npz').files Out[5]: ['y', 'x', 'u', 'v'] In [6]: load('xy_uv.npz')['u'] --------------------------------------------------------------------------- BadZipfile Traceback (most recent call last) /Users/jsw/python/basemap/<ipython console> in <module>() /opt/local/lib/python2.5/site-packages/numpy/lib/io.pyc in __getitem__(self, key) 110 key += '.npy' 111 if member: --> 112 bytes = self.zip.read(key) 113 if bytes.startswith(format.MAGIC_PREFIX): 114 value = cStringIO.StringIO(bytes) /opt/local/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/zi pfile.pyc in read(self, name) 477 fheader = self.fp.read(30) 478 if fheader[0:4] != stringFileHeader: --> 479 raise BadZipfile, "Bad magic number for file header" 480 481 fheader = struct.unpack(structFileHeader, fheader) BadZipfile: Bad magic number for file header -Jeff > Here's my basemap setup... > m=bm(projection='cyl',llcrnrlat=20,urcrnrlat=30,llcrnrlon=-100,urcrnrlon=-80 > ,resolution='h') > > though it might not help much, here's the exact export from pygrads > (ga.expr() exports from grads into a customized masked array in python) > 'dirpw' is the grads variable being imported into mpl. > > U = ga.expr('(-1*sin(dirpw*3.1414/180))') > V = ga.expr('(-1*cos(dirpw*3.1414/180))') > X,Y=m(*np.meshgrid(U.grid.lon,U.grid.lat)) > > I then was also doing this to convert to simple ndarrays > (a while back, I was recommended this method to solve a problem I was having > with quiver performing really slowly when using those grads masked arrays as > input) > > x,y,u,v = delete_masked_points(X.ravel(), Y.ravel(), U.ravel(), V.ravel()) > > Let me know if you need anything else... > > Thanks, > P.R. > > > -----Original Message----- > From: Jeff Whitaker [mailto:jsw...@fastmail.fm] > Sent: 2009-08-11 9:26 PM > To: P.R. > Cc: matplotlib-users@lists.sourceforge.net > Subject: Re: [Matplotlib-users] problem with basemap/quiver with latest > versions of basemap&mpl > > P.R. wrote: > >> Hi, >> I just updated to the latest versions of mpl & basemap. >> Im getting strange output when using the quiver function from basemap (see >> attached image). >> >> I ran the quiver_demo scripts for both basemap & also mpl, and the output >> looked normal. >> >> Im using pygrads, a python interface to GrADS, in order to generate my >> X,Y,U,V input arrays for quiver. >> I can provide these arrays if needed... >> >> The data imported using pygrads previously worked fine (prior to updating >> > to > >> the new versions). >> >> Before I start diving into the pygrads code in order to troubleshoot, I >> wanted to first check to see if this issue is a possible quiver bug in the >> new version(s)... >> >> Or, were there any significant changes to the mpl/basemap code with >> > respect > >> to how quiver works??? >> >> Here's the basic method Im using... >> U = <my_pygrads_imported_U> >> V = <my_pygrads_imported_V> >> X,Y=m(*np.meshgrid(U.grid.lon,U.grid.lat)) >> #x,y,u,v = delete_masked_points(X.ravel(), Y.ravel(), U.ravel(), >> > V.ravel()) > >> cs2 = m.quiver(X,Y,U,V,*kwargs) >> >> again, this *used* to work fine, prior to the updates... >> >> Please help, >> Thanks, >> P.Romero >> >> > > P.R.: I can't see anything wrong - you'd better post your data so we > can try it. You might also try to upgrade to numpy 1.3.0, if you > haven't already, I know there were some masked array changes between > 1.2.1 and 1.3. > > -Jeff ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
