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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