SF.net SVN: matplotlib: [4964] trunk/toolkits/basemap/examples/warpimage.py

[<js...@us...>]

Revision: 4964
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=4964&view=rev
Author:   jswhit
Date:     2008-02-14 14:07:41 -0800 (Thu, 14 Feb 2008)

Log Message:
-----------
subclass Basemap, make a 'bluemarble' method.

Modified Paths:
--------------
    trunk/toolkits/basemap/examples/warpimage.py

Modified: trunk/toolkits/basemap/examples/warpimage.py
===================================================================
--- trunk/toolkits/basemap/examples/warpimage.py	2008-02-14 21:51:58 UTC (rev 4963)
+++ trunk/toolkits/basemap/examples/warpimage.py	2008-02-14 22:07:41 UTC (rev 4964)
@@ -1,30 +1,50 @@
 import pylab as P
 import numpy
-from mpl_toolkits.basemap import Basemap
+from mpl_toolkits.basemap import Basemap as Basemap1 
 from numpy import ma
 from matplotlib.image import pil_to_array
 from PIL import Image
 
-# shows how to warp an image from one map projection to another.
-# 'blue marble next generation' image from http://visibleearth.nasa.gov/
+class Basemap(Basemap1):
+    # subclass Basemap and add bluemarble method.
+    def bluemarble(self,masked=False):
+        """display 'blue marble next generation' image from http://visibleearth.nasa.gov/"""
+        
+        # read in jpeg image to rgba array of normalized floats.
+        pilImage = Image.open('bmng.jpg')
+        rgba = pil_to_array(pilImage)
+        rgba = rgba.astype(numpy.float32)/255. # convert to normalized floats.
+        
+        # define lat/lon grid that image spans (projection='cyl').
+        nlons = rgba.shape[1]; nlats = rgba.shape[0]
+        delta = 360./float(nlons)
+        lons = numpy.arange(-180.+0.5*delta,180.,delta)
+        lats = numpy.arange(-90.+0.5*delta,90.,delta)
 
-# read in jpeg image to rgba array of normalized floats.
-pilImage = Image.open('bmng.jpg')
-rgba = pil_to_array(pilImage)
-rgba = rgba.astype(numpy.float32)/255. # convert to normalized floats.
+        if self.projection != 'cyl':
+            # transform to nx x ny regularly spaced native projection grid
+            # nx and ny chosen to have roughly the same horizontal res as original image.
+            dx = 2.*numpy.pi*m.rmajor/float(nlons)
+            nx = int((self.xmax-self.xmin)/dx)+1; ny = int((self.ymax-self.ymin)/dx)+1
+            rgba_warped = ma.zeros((ny,nx,4),numpy.float64)
+            # interpolate rgba values from proj='cyl' (geographic coords) to 'lcc'
+            # if masked=True, values outside of projection limb will be masked.
+            for k in range(4):
+                rgba_warped[:,:,k] = self.transform_scalar(rgba[:,:,k],lons,lats,nx,ny,masked=masked)
+            # make points outside projection limb transparent.
+            rgba_warped = rgba_warped.filled(0.)
+            # plot warped rgba image.
+            im = self.imshow(rgba_warped)
+        else:
+            im = self.imshow(rgba)
+        return im
 
-# define lat/lon grid that image spans (projection='cyl').
-nlons = rgba.shape[1]; nlats = rgba.shape[0]
-delta = 360./float(nlons)
-lons = numpy.arange(-180.+0.5*delta,180.,delta)
-lats = numpy.arange(-90.+0.5*delta,90.,delta)
-
 # create new figure
 fig=P.figure()
 # define cylindrical equidistant projection.
 m = Basemap(projection='cyl',llcrnrlon=-180,llcrnrlat=-90,urcrnrlon=180,urcrnrlat=90,resolution='l')
 # plot (unwarped) rgba image.
-im = m.imshow(rgba)
+im = m.bluemarble()
 # draw coastlines.
 m.drawcoastlines(linewidth=0.5,color='0.5')
 # draw lat/lon grid lines.
@@ -37,19 +57,8 @@
 fig=P.figure()
 # define orthographic projection centered on North America.
 m = Basemap(projection='ortho',lat_0=40,lon_0=40,resolution='l')
-# transform to nx x ny regularly spaced native projection grid
-# nx and ny chosen to have roughly the same horizontal res as original image.
-dx = 2.*numpy.pi*m.rmajor/float(nlons)
-nx = int((m.xmax-m.xmin)/dx)+1; ny = int((m.ymax-m.ymin)/dx)+1
-rgba_warped = ma.zeros((ny,nx,4),numpy.float64)
-# interpolate rgba values from proj='cyl' (geographic coords) to 'lcc'
-# values outside of projection limb will be masked.
-for k in range(4):
-    rgba_warped[:,:,k] = m.transform_scalar(rgba[:,:,k],lons,lats,nx,ny,masked=True)
-# make points outside projection limb transparent.
-rgba_warped = rgba_warped.filled(0.)
 # plot warped rgba image.
-im = m.imshow(rgba_warped)
+im = m.bluemarble(masked=True)
 # draw coastlines.
 m.drawcoastlines(linewidth=0.5,color='0.5')
 # draw lat/lon grid lines every 30 degrees.
@@ -64,16 +73,7 @@
 m = Basemap(llcrnrlon=-145.5,llcrnrlat=1.,urcrnrlon=-2.566,urcrnrlat=46.352,\
             rsphere=(6378137.00,6356752.3142),lat_1=50.,lon_0=-107.,\
             resolution='i',area_thresh=1000.,projection='lcc')
-# transform to nx x ny regularly spaced native projection grid
-# nx and ny chosen to have roughly the same horizontal res as original image.
-dx = 2.*P.pi*m.rmajor/float(nlons)
-nx = int((m.xmax-m.xmin)/dx)+1; ny = int((m.ymax-m.ymin)/dx)+1
-rgba_warped = numpy.zeros((ny,nx,4),numpy.float64)
-# interpolate rgba values from proj='cyl' (geographic coords) to 'lcc'
-for k in range(4):
-    rgba_warped[:,:,k] = m.transform_scalar(rgba[:,:,k],lons,lats,nx,ny)
-# plot warped rgba image.
-im = m.imshow(rgba_warped)
+im = m.bluemarble()
 # draw coastlines.
 m.drawcoastlines(linewidth=0.5,color='0.5')
 # draw parallels and meridians.
@@ -91,19 +91,8 @@
 m = Basemap(height=24000000,width=12000000,
             resolution=None,projection='omerc',\
             lon_0=-100,lat_0=15,lon_2=-120,lat_2=65,lon_1=-50,lat_1=-55)
-# transform to nx x ny regularly spaced native projection grid
-# nx and ny chosen to have roughly the same horizontal res as original image.
-dx = 2.*numpy.pi*m.rmajor/float(nlons)
-nx = int((m.xmax-m.xmin)/dx)+1; ny = int((m.ymax-m.ymin)/dx)+1
-rgba_warped = ma.zeros((ny,nx,4),numpy.float64)
-# interpolate rgba values from proj='cyl' (geographic coords) to 'lcc'
-# values outside of projection limb will be masked.
-for k in range(4):
-    rgba_warped[:,:,k] = m.transform_scalar(rgba[:,:,k],lons,lats,nx,ny,masked=False)
-# make points outside projection limb transparent.
-rgba_warped = rgba_warped.filled(0.)
 # plot warped rgba image.
-im = m.imshow(rgba_warped)
+im = m.bluemarble()
 # draw lat/lon grid lines every 20 degrees.
 m.drawmeridians(numpy.arange(0,360,20),color='0.5')
 m.drawparallels(numpy.arange(-80,81,20),color='0.5')


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