Timeline for How to get all the sub-rectangles (subgeohashes) of a given geohash
Current License: CC BY-SA 4.0
4 events
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| Jul 21, 2019 at 13:07 | comment | added | John Powell | Yes, because one letter of a base32 encoding is 5 bits. From the wikipedia article, the first "letter" of the base32 alphabet is 0, which corresponds to 00000 and the last letter is z, which corresponds to 11111, ie, 31. So, one level down in the quad tree, will add 10 bits, 5 for each direction. | |
| Jul 21, 2019 at 13:00 | comment | added | tinlyx | I am uncertain because going down one level of a quad-tree should add two-bits, but adding one letter in geohash seems to add 5-bit to it. Again, this is because I don't know much about geohash, and whether its hierarchical approximated code systems maps to quad-trees. | |
| Jul 21, 2019 at 12:57 | comment | added | tinlyx |
Thanks for the detailed answer. What I was looking for is a way to enumerate e.g. 4-letter geohash codes that "bleong to" the 3-letter code geographically. In your example, sp3 has sp3e obviously. But what are the others? Is it sp3[0-9,a-z]? Then, similarly what are the 5-letter codes.
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| Jul 21, 2019 at 12:46 | history | answered | John Powell | CC BY-SA 4.0 |