def zoom_map(self, buffer=0.2,
lonmin=None, lonmax=None, latmin=None, latmax=None):
self.logger.info('Zooming basemap to (%s to %s E), (%s to %s N)' %
(lonmin, lonmax, latmin, latmax) )
map = Basemap(lonmin, latmin, lonmax, latmax,
resolution=None, projection='merc')
# Find Basemap offset between new and old maps
xo, yo = map(lonmin, latmin, inverse=False)
xoo, yoo = self.map(lonmin, latmin, inverse=False)
xoff = xoo-xo
yoff = yoo-yo
# Copy polygons and adjust for offsets
map.coastpolygons = [
(tuple(np.subtract(pol[0], xoff)),
tuple(np.subtract(pol[1], yoff))) for pol in
self.map.coastpolygons]
coastsegs_new = []
for c in self.map.coastsegs:
xc, yc = list(zip(*c))
newxc = tuple(xce - xoff for xce in xc)
newyc = tuple(yce - yoff for yce in yc)
coastsegs_new.append(list(zip(newxc, newyc)))
map.coastsegs = coastsegs_new
map.coastpolygontypes = map_orig.coastpolygontypes
map.resolution = map_orig.resolution
self.map = map
