Demonstration of the tiling mechanism in Google maps

Click here to show and hide a GPolyLine drawn from 30°N 120°W to 40°N 100°W. By zooming in, you should see that the line is clipped linearly (e.g. passes through 35°N 100°W), not according to the mercator projection (which would have it pass through 35.1534°N 100°W). More detail at the technical faq.