Module morton 

The fixed lookup grid.

Longitude and latitude are each mapped onto 16 bits and interleaved into a 32-bit Z-order key, so that a quadtree cell at any depth is one contiguous range of keys and a lookup is a single indexed query.

Every operation here has an exact counterpart in the Python builder (tools/regiondb-build/src/regiondb_build/morton.py). Both are written as the same two floating-point operations rather than in whichever idiom each language finds natural, because a position that lands in different cells on different platforms would be a lookup that disagrees with itself.

Enums

MortonError

A coordinate that cannot be placed on the grid.

Constants

GRID

Cells per axis at maximum depth.

MAX_DEPTH

Depth of the grid: 16 bits per axis, so cells are roughly 600 m by 300 m at the equator.

Functions

cell_xy

Grid coordinates of the cell containing a position.

check_latitude

Validate latitude, which is clamped into the grid rather than wrapped.

interleave

Interleave two 16-bit values, x into the even bits.

key

The maximum-depth Morton key for a position.

normalize_longitude

Wrap longitude into [-180, 180).