Apparatus and method for forming a grid-based geospatial primary index and secondary index

1. A method implemented by a computer with a processor and a memory storing instructions executed by the processor, comprising:

mapping a geographic input region to a set of blocks;

for each block in the set of blocks:

transforming ellipsoidal geographic coordinates of the geographic input region to flat coordinates,

storing the block in a primary index when the block does not contain a boundary of the geographic input region to form a non-boundary entry,

storing the block in a secondary index when the block does contain a boundary of the geographic input region to form a boundary entry;

after mapping the geographic input region to the set of blocks, resolving a geospatial query including a query geohash utilizing the primary index and the secondary index to identify stored non-boundary entries and stored boundary entries that correspond to the query geohash; and

returning to a user the stored non-boundary entries and stored boundary entries that correspond to the query geohash.

2. The method of claim 1 further comprising storing for each block in the set of blocks a prefix string.

3. The method of claim 2 wherein the prefix string is a geohash.

4. The method of claim 2 further comprising storing for each block in the set of blocks prefix sub-strings derived from the prefix string.

5. The method of claim 4 wherein the prefix sub-strings are geohash substrings derived from a geohash prefix string.