All, We try to generate contour polygons from an unstructured triangular grid stored in a netcdf file:
import netCDF4 import matplotlib.tri as tri # read data var = netCDF4.Dataset('filename.cdf').variables x = var['x'][:] y = var['y'][:] elems = var['element'][:,:]-1 data = var['attrname'][:] # create triangulation triang = tri.Triangulation(x, y, triangles=elems) # generate contour polygons levels = numpy.linspace(0, maxlevel, num=numlevels) contour = plt.tricontourf(triang, data, levels=levels) # extract geometries for coll in contour.collections: # handle all geometries for one level for p in coll.get_paths(): polys = p.to_polygons() ... At this point we assume, that polys[0] is a linear ring to be interpreted as a polygon exterior and polys[1:] are the corresponding interiors for polys[0]. Here are our questions: Is this assumption correct? Is there any detailed documentation describing the structure of the returned geometries? Are the linear rings supposed to be correctly oriented (area > 0 for exteriors and area < 0 for the interiors)? Thanks! Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu ------------------------------------------------------------------------------ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users