tile_index = pd.read_csv('../tile_index.dat', names=['tile', 'x', 'y'], sep=' ')
geometry = [Point(r.x, r.y) for ix, r in tile_index.iterrows()]
tile_index = gp.GeoDataFrame(tile_index, geometry=geometry)
tile_index = tile_index[(tile_index.x.between(-10, 30)) & (tile_index.y.between(-10, 30))]
print tile_index.head()

tile      x       y                                        geometry
202   226 -9.226  -0.724  POINT (-9.226000000000001 -0.7240000000000001)
203   227 -9.226   9.276                POINT (-9.226000000000001 9.276)
204   228 -9.226  19.276               POINT (-9.226000000000001 19.276)
205   229 -9.226  29.276               POINT (-9.226000000000001 29.276)
219   243  0.774  -0.724               POINT (0.774 -0.7240000000000001)

poly = Polygon([(0, 0), (0, 20), (20, 20), (20, 0)])
P = gp.GeoDataFrame(data=[1, poly]).T
P.columns = ['ID', 'geometry']
print np.any(tile_index.within(P))

pt = Point(10.774, 9.276)
p = gp.GeoDataFrame([[1, pt]])
p.columns = ['ID', 'geometry']
print p.within(P)