How can I divide the globe in to small grids such that it allows me to assign each lat/long location to a grid? [closed]

Question

In order to calculate the nearest locations that are represented by latitude/longitude, I was considering dividing the map into small grids, approximately 100x100 meter grids. Essentially each point would be assigned to a grid.

I understand that I could instead also use spatial indexes with MySQL etc, but am planning to use a non-relational database like Cassandra where it would be difficult to do indexing on spatial objects, and so some kind of grid approximation technique could be neat.

What would be the best way of creating such a grid system and mapping the 2-D spatial locations to it?

Edit1: It might be alright if the grids are not perfectly uniform, more so around the poles.

Answer 1

Mapping from the two-dimensional spatial coordinates to your spatial index / geohash is an interesting problem. You might look at this article on quadtrees, geohashes and Hilbert curves. The Hilbert curve is a space-filling curve that provides locality; for your purposes, that means that nearby items in the one-dimensional spatial index will be nearby in two-dimensional space.

The goal (as described by other responders) is to minimize the number of queries necessary to cover the space in question without requesting tons of unnecessary data from the server. How you do the mapping from 2-d space to a 1-d index will affect that goal.