On Fri, Apr 2, 2010 at 1:23 AM, Eric Firing <efir...@hawaii.edu> wrote: >> On Fri, Mar 26, 2010 at 12:13 PM, Ryan May <rma...@gmail.com> wrote: >>> I just hit a problem with using quiver with Basemap when when >>> angles='xy'. Because Basemap's x,y units are in meters, you end up >>> with angles that are quantized due to floating point truncation >>> (30000. + 0.001*u = 30000.). Changing to angles='uv' fixes the >>> problem, but it probably should be automatically scaled, as noted in >>> the comments: >>> >>> elif self.angles == 'xy' or self.scale_units == 'xy': >>> # We could refine this by calculating eps based on >>> # the magnitude of U, V relative to that of X, Y, >>> # to ensure we are always making small shifts in X, Y. >>> >>> I managed to fix the problem locally by setting: >>> >>> angles, lengths = self._angles_lengths(U, V, eps=0.0001 * >>> self.XY.max()) >>> > > I don't think this will work in all cases. For example, there could be a > single arrow at (0,0).
Good point. > Instead of self.XY.max(), how about abs(self.ax.dataLim.width)? Wouldn't this have problems if we zoom in sufficiently that the width is much less than magnitude of the values? Not exactly sure what data set would sensibly yield this, so I'm not sure if we should worry about it. If we do care, we could just put a minimum bound on eps: eps=max(1e-8, 0.0001 * self.XY.max()) Ryan -- Ryan May Graduate Research Assistant School of Meteorology University of Oklahoma ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
