API Overview

The IGEO7 API is documented here in a language-agnostic style — function names and signatures describe the operation, then each section shows the Python (dggrid4py) binding.

Function Categories

Category	What it does	Page
Indexing	Convert coordinates ↔ cell IDs	Indexing
Inspection	Query properties of a cell ID	Inspection
Hierarchy	Parent, children, ancestors	Hierarchy
Traversal	Neighbours, grid disks	Traversal
Regions	Polygon ↔ cell ID sets	Regions
Miscellaneous	Resolution lookup, stats	Miscellaneous

Index Formats

All functions accept and return cell IDs in one of three interchangeable formats:

Format	Example	Notes
Z7 string	"0800433"	Human-readable; length = 2 + resolution
Z7 hex	"0042aad3ffffffff"	16 lowercase hex chars; matches H3 string length
Z7 integer	0x0042aad3ffffffff	Raw uint64; fastest for arithmetic

See Z7 String Format and Z7 Bit Layout for encoding details.

Python Binding: dggrid4py

The primary Python API is split across two modules:

from dggrid4py import DGGRIDv7   # grid generation and coordinate conversion
from dggrid4py import igeo7       # Z7 index arithmetic (no DGGRID process needed)

DGGRIDv7 calls the DGGRID binary for coordinate-intensive operations (point indexing, polygon filling, geometry generation). igeo7 is pure Python for index inspection and format conversion.

Initialising DGGRIDv7

import os
from dggrid4py import DGGRIDv7

dggrid = DGGRIDv7(
    executable=os.environ.get("DGGRID_PATH", "/usr/local/bin/dggrid"),
    working_dir="/tmp",
    capture_logs=False,
    silent=True,
)

Julia Binding: IGEO7.jl

IGEO7.jl implements the full Z7 index arithmetic natively in Julia, including neighbour traversal. It does not wrap DGGRID.

using IGEO7

idx = z7string_to_index("0800433")
res = get_resolution(idx)          # 5
parent = get_parent(idx)           # Z7IndexUInt64 at resolution 4

Address Type Reference

When calling dggrid4py functions, the input_address_type and output_address_type parameters accept:

Value	Format
"Z7_STRING"	Z7 string (e.g. "0800433")
"Z7"	Z7 hex string (e.g. "0042aad3ffffffff")
"SEQNUM"	DGGRID sequential number (internal)
"Q2DI"	Quad/diamond index (DGGRID internal)
"PROJTRI"	Projected triangle coordinates