Draggable Tissot Indicatrix


Slow afternoon = time to play with Google Maps API. Lots of people bash Google and other slippy maps for using web mercator. Yes, it is distorted, but aren’t they all? Personally, I don’t have a serious problem with the distortion – I know it’s there. The “danger,” if there is one, is that some people don’t know mercator is distorted and go about their day thinking Greenland is the same size as South America (the horror). So, to help remind us all that mercator distorts area, here is a Google Maps API-based Tissot Indicatrix showing what happens to a 500km circle placed anywhere on the map (they are all 500km radius). And I do mean anywhere – you can drag the circles. Watch them change size, and get all funky at the poles.

UPDATE: this post has been featured in Google Maps Mania!


One thought on “Draggable Tissot Indicatrix

  1. Felipe G. Nievinski

    Very nice! Could you draw a cross at the center of each circle? Then we could visualize torsion too! Thanks.


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