Resolution Table

IGEO7 has 21 resolution levels (0–20). At every refinement level, the grid contains exactly 12 pentagons (at icosahedron vertices) and all remaining cells are hexagons. Level 0 is only the 12 base pentagons.

CLS (Characteristic Length Scale) is the diameter of a circle with the same area as a cell — the most intuitive way to relate IGEO7 resolutions to traditional raster pixel sizes.

Full Table

Res	Total Cells	Hexagons	Pentagons	Area (km²)	Area (m²)	CLS (km)	CLS (m)
0	12	0	12	51,006,562.172	51,006,562,172,408.9	8,199.500	8,199,500.4
1	72	60	12	7,286,651.739	7,286,651,738,915.6	3,053.223	3,053,223.2
2	492	480	12	1,040,950.248	1,040,950,248,416.5	1,151.643	1,151,643.0
3	3,432	3,420	12	148,707.178	148,707,178,345.2	435.153	435,153.1
4	24,012	24,000	12	21,243.883	21,243,882,620.7	164.466	164,465.6
5	168,072	168,060	12	3,034.840	3,034,840,374.4	62.162	62,161.8
6	1,176,492	1,176,480	12	433.549	433,548,624.9	23.495	23,494.9
7	8,235,432	8,235,420	12	61.936	61,935,517.8	8.880	8,880.2
8	57,648,012	57,648,000	12	8.848	8,847,931.1	3.356	3,356.4
9	403,536,072	403,536,060	12	1.264	1,263,990.2	1.269	1,268.6
10	2,824,752,492	2,824,752,480	12	0.181	180,570.0	0.479	479.5
11	19,773,267,432	19,773,267,420	12	0.026	25,795.7	0.181	181.2
12	138,412,872,012	138,412,872,000	12	0.004	3,685.1	0.068	68.5
13	968,890,104,072	968,890,104,060	12	~0	526.4	~0.026	25.9
14	6,782,230,728,492	6,782,230,728,480	12	~0	75.2	~0.010	9.8
15	47,475,615,099,432	47,475,615,099,420	12	~0	10.7	~0.004	3.7
16	332,329,305,696,012	332,329,305,696,000	12	~0	1.5	~0.001	1.4
17	2,326,305,139,872,072	2,326,305,139,872,060	12	~0	0.2	~0	0.528
18	16,284,135,979,104,492	—	12	~0	~0.032	~0	0.200
19	113,988,951,853,731,432	—	12	~0	~0.005	~0	0.076
20	797,922,662,976,120,012	—	12	~0	~0.001	~0	0.029

Area values for resolutions 18–20

Cell areas at resolutions 18–20 are below IEEE 754 double precision representation in km². The m² values shown are approximations. CLS values from the authoritative IGEO7.jl implementation.

Landmark Resolutions

These resolutions are particularly useful reference points:

Resolution	CLS	Comparable to
5	~62 km	Country-level analysis, climate zones
7	~8.9 km	Urban areas, municipalities
8	~3.4 km	Neighbourhoods, large parks
9	~1.3 km	"Kilometre grid" — comparable to 1 km raster
10	~480 m	Streets, large buildings
11	~181 m	Individual fields, city blocks
12	~68 m	Parcels, small fields
14	~9.8 m	Comparable to 10 m Sentinel-2 resolution
15	~3.7 m	High-resolution aerial imagery
17	~53 cm	Sub-metre precision
18	~20 cm	Centimetre-scale (LiDAR point clouds)
20	~2.9 cm	Engineering precision

Cell Count Formula

The total number of cells at resolution $r$ is:

$$c(r) = 2 + \frac{(7^{r+1} - 7) \times 10}{7}$$

Equivalently: start with 12 cells at resolution 0. At each subsequent resolution, every hexagon subdivides into 7 children. Pentagons also subdivide but only into 6 actual new children (they share one child with neighbours).

At every resolution:

• 12 pentagons (centred on the 12 icosahedron vertices)
• All other cells are hexagons

Comparison with H3

Property	IGEO7	H3
Resolution levels	21 (0–20)	16 (0–15)
Finest resolution CLS	~2.9 cm (res 20)	~0.9 m² area (res 15)
Coarsest resolution cells	12 (res 0)	122 (res 0)
Cell area variation	0% (equal area)	±50%

IGEO7 has 5 more resolution levels than H3 because it starts from a pure icosahedral base (12 pentagonal base cells) rather than H3's mixed aperture 4→3 pre-subdivision (122 base cells).

Generate the stats with dggrid4py

from dggrid4py import DGGRIDv7
import os

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

# yes, ISEA7H, IGEO7 is not recognized as a grid for resolutions in itself :-)
df = dggrid.grid_stats_table("ISEA7H", 20)
print(df.to_string())