Michael Bauer wrote: > I'd like to make pcolor images using non-'cyl' projections, but I want > the pcolor pixels to be trapezoidal rather than rectangular. Is this > possible? > > Mike > > Example script" > > # example data > lonin = numpy.arange(0.,360.,2.5) > latin = numpy.arange(-90.,92.5,2.5) > field = numpy.ones([len(latin),len(lonin)]) + > 10.0*numpy.random.random([len(latin),len(lonin)]) > > # adapt for plot > #field,lons = addcyclic(field,lonin) > #field,lons = shiftgrid(180.,field,lons,start=False) > # offset for pcolor > field = 0.5*(field[:-1,:-1]+field[1:,1:]) > > fig = figure() > canvas = FigureCanvas(fig) > the_map = Basemap(resolution='c',projection='lcc',llcrnrlon=-75., > llcrnrlat=15.,urcrnrlon=40.,urcrnrlat=60.,lat_1=50., > lon_0=-45.) > > # convert to projected coordinates > dx = 2.*pi*the_map.rmajor/len(lons) > nx = int((the_map.xmax-the_map.xmin)/dx)+1 > ny = int((the_map.ymax-the_map.ymin)/dx)+1 > z,x,y = > the_map.transform_scalar(field,lons,lats,nx,ny,returnxy=True,order=0) > > # creates seemingly correct image in term of grid placement, but with > rectangular pixels > the_image = the_map.pcolor(x,y,z,shading='flat') > > Mike: There's no need to do the interpolation to map projection coordinates. Just pass pcolor the vertices of the lat/lon grid in map projection coordinates, i.e.
x,y = the_map(lons, lats) the_image = the_map.pcolor(x,y,field) The resulting pixels will not be square, but will have the shape of lat/lon boxes in projected coordinates. -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449 325 Broadway Boulder, CO, USA 80305-3328 ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
