wmsimage_grayscale.patch

--- __init__.py.old	2014-10-07 01:26:24.682034979 +0200
+++ __init__.py	2014-10-07 14:48:02.542868362 +0200
@@ -4272,7 +4272,7 @@
         return self.imshow(imread(urllib2.urlopen(basemap_url)),origin='upper')
 
     def wmsimage(self,server,\
-                 xpixels=400,ypixels=None,\
+                 xpixels=400,ypixels=None,togray=False,\
                  format='png',verbose=False,**kwargs):
         """
         Retrieve an image using from a WMS server using the
@@ -4357,8 +4357,21 @@
                          srs='EPSG:%s' % self.epsg, **kwargs)
         # return AxesImage instance.
         # this works for png and jpeg.
-        return self.imshow(imread(io.BytesIO(urllib2.urlopen(img.url).read()),
-                           format=format),origin='upper')
+        im = imread(io.BytesIO(urllib2.urlopen(img.url).read()),
+                    format=format)
+        if togray and im.shape[2] >= 3:
+            if togray is True:
+                togray = [0.3, 0.6, 0.1]
+            else:
+                assert len(togray) == 3, \
+                    '`togray` must be either False, True or [r, g, b].'
+            gray = (togray[0] * im[:,:,0] +
+                    togray[1] * im[:,:,1] +
+                    togray[2] * im[:,:,2])
+            im[:,:,0] = gray
+            im[:,:,1] = gray
+            im[:,:,2] = gray
+        return self.imshow(im,origin='upper')
         # this works for png, but not jpeg
         #return self.imshow(imread(urllib2.urlopen(img.url),format=format),origin='upper')