shape encoding

[kevinkreiser]

(2016-04-04T19:17:33Z) @kevinkreiser : originally created valhalla/midgard#80

polyline encoding is great because its pretty standard across the mapping world. its nice because it results in chars in the visible ascii range. but strictly speaking we dont care about viewing it when we use it to store shape in routing tiles. can we make use of even the invisible ascii range to save even more space (by having more precision per byte), indeed can we use another offset encoding scheme to do it faster or with less storage. do some research to test this...

(2016-05-16T14:07:32Z) @kevinkreiser : this has been done as of a few weeks ago