z7py implements the Z7 indexing system for the IGEO7 / ISEA7H aperture-7 hexagonal discrete global grid, based on the Generalized Balanced Ternary (GBT) numeral system with the alternating CW/CCW rotation pattern.

Z7 indices are bit-packed into a single uint64 (4 bits base cell, 20 x 3 bits resolution digits), which makes neighbour traversal, parent/child navigation and monotonic range arithmetic pure integer operations. The hot paths are JIT-compiled with Numba.

The package is deliberately thin: it depends only on NumPy and Numba, and needs neither the DGGRID binary nor a geospatial stack, so it can be used inside Numba nopython kernels and on bare compute workers.