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interesting. does your book cover geohashing. I've been curious how points and polygons get converted to geohashes and how the search using these work. I curren
by cultofmetatron 4y ago
interesting. does your book cover geohashing. I've been curious how points and polygons get converted to geohashes and how the search using these work. I currently postgis as a black box but I haven't been able to find any books or articles that really explain in depth how they work.
- zlurker 4y agoThere's a great blog written by someone who wrote a very efficient geohashing algorithm in go/assembly that may help a little bit with understanding it. https://mmcloughlin.com/posts/geohash-assembly https://mmcloughlin.com/posts/geohash-assembly The simplified TLDR is: 1. Convert lat and long to something that's represented by bits. 2. Interleave these bits such that lat and long bits alternate in the sequence. 3. Optionally, but seems to be the standard, encode the bits into the custom base32 character set.
- cultofmetatron 4y agothanks for the link. I would pay good money for a book that explains in plain english and a few go/python examples how these are implemented and the theory behind them.
- yencabulator 4y agoS2 has a good amount of documentation about it. https://s2geometry.io/ https://s2geometry.io/ https://blog.christianperone.com/2015/08/googles-s2-geometry-on-the-sphere-cells-and-hilbert-curve/?a=2 https://blog.christianperone.com/2015/08/googles-s2-geometry...