Example demonstrating collecting a list of points into a mapnik.Box2d and then slightly expanding it

mapnik-bbox-expansion.py

import mapnik

points = [[-122,48],[-120,45],[-90,43]]

bbox = None

for idx, point in enumerate(points):
  if idx == 0:
      bbox = mapnik.Box2d(point[0],point[1],point[0],point[1])
  else:
      bbox.expand_to_include(mapnik.Coord(point[0],point[1]))

print 'bbox inclusive of all points'
print bbox

bbox *= 1.1
print 'bbox inflated slightly, by 1.1 times'
print bbox