4 ms·

Doing this saves you about two bits worth of information while usually greatly increasing complexity. To see why consider how geohashes work. As you add letter

Doing this saves you about two bits worth of information while usually greatly increasing complexity. To see why consider how geohashes work. As you add letters you telescope in to a more precise region. The land/water distinction is less information than even what is encoded by the very first character of your 9 or 10 character geohash.

logfromblammo 7y ago
If one could maintain an index of a single reference point for human settlements, as geodetic latitude and longitude, addresses could relatively reference from a specific center, and include relative waypoints. us;il;chi = {41.88206,-87.62781} The Chicago base reference point, positive x-axis points to 0 degrees N, positive y-axis points to 90 degrees east. us;il;chi;0,0 = Madison and State, street level us;il;chi;-278,+305 = 111 S. Michigan, street level. This is between the lions of the Art Institute. Horizontal offsets are in meters. us;il;chi;-278,+305>90:165 = east 165m into the museum, over the bridge, into Greek, Roman, and Byzantine art. us;il;chi;-278,+305>90:165>180:32,+1 = south 32m into the Modern American Art wing, up the stairs one level, in the top level of the 2-level sculpture court. Vertical offset is in building stories. us;il;chi;-278,+305>90:165>180:32,+1>270:13 = west 13m into gallery 262, home of Nighthawks. A geohash can tell you where Nighthawks is, in terms of a geodetic location to a certain precision, but it doesn't tell you that it's on the second floor of a building whose second floors don't all connect, or how to get there to see it. If doesn't matter how many extra characters of precision you add when the place you want to be is separated from the locations of the public access points. Addressing sometimes has to include routing information. Complexity is sometimes needed. The base reference point for Manhattan (us;ny;nyc) could have its reference grid rotated to 29 degrees NNE, but cities without a grid system needn't bother.

logfromblammo 7y ago

If one could maintain an index of a single reference point for human settlements, as geodetic latitude and longitude, addresses could relatively reference from a specific center, and include relative waypoints. us;il;chi = {41.88206,-87.62781} The Chicago base reference point, positive x-axis points to 0 degrees N, positive y-axis points to 90 degrees east. us;il;chi;0,0 = Madison and State, street level us;il;chi;-278,+305 = 111 S. Michigan, street level. This is between the lions of the Art Institute. Horizontal offsets are in meters. us;il;chi;-278,+305>90:165 = east 165m into the museum, over the bridge, into Greek, Roman, and Byzantine art. us;il;chi;-278,+305>90:165>180:32,+1 = south 32m into the Modern American Art wing, up the stairs one level, in the top level of the 2-level sculpture court. Vertical offset is in building stories. us;il;chi;-278,+305>90:165>180:32,+1>270:13 = west 13m into gallery 262, home of Nighthawks. A geohash can tell you where Nighthawks is, in terms of a geodetic location to a certain precision, but it doesn't tell you that it's on the second floor of a building whose second floors don't all connect, or how to get there to see it. If doesn't matter how many extra characters of precision you add when the place you want to be is separated from the locations of the public access points. Addressing sometimes has to include routing information. Complexity is sometimes needed. The base reference point for Manhattan (us;ny;nyc) could have its reference grid rotated to 29 degrees NNE, but cities without a grid system needn't bother.