https://github.com/kevinmichaelchen/api-geo-h3

ꙮ gRPC API over H3 (hexagonal hierarchical geospatial indexing system)
https://github.com/kevinmichaelchen/api-geo-h3

Last synced: about 2 months ago
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ꙮ gRPC API over H3 (hexagonal hierarchical geospatial indexing system)

• Host: GitHub
• URL: https://github.com/kevinmichaelchen/api-geo-h3
• Owner: kevinmichaelchen
• Created: 2022-04-30T01:13:34.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2022-04-30T03:28:30.000Z (over 2 years ago)
• Last Synced: 2024-06-20T19:35:12.772Z (7 months ago)
• Language: Go
• Homepage:
• Size: 501 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# api-geo-h3

This is a proof-of-concept component that wraps [H3](https://h3geo.org/),

a hexagonal hierarchical geospatial indexing system.



For dispatch, our geospatial needs can be satisfied in the simplest way by

asking: given a trip pickup location, which (drivers') coordinates are the

closest.

This can be done with [`GeoToH3`](https://h3geo.org/docs/api/indexing/#geotoh3)

(for converting geographic coordinates to a hex cell index) and with

[`H3Distance`](https://h3geo.org/docs/api/traversal#h3distance) (which returns

the distance in grid cells between two indexes).

### What resolution do we use?

Brooklyn is 250 sq km (one cell at Resolution 5)...

Williamsburg is 5 sq km (one cell at Resolution 7)...

Each finer-resolution cell is 7 times smaller than its coarser parent.

H3 supports [multiple resolutions](https://h3geo.org/docs/core-library/restable):

| H3 Resolution | Average Hexagon Area (km 2) | Average Hexagon Edge Length (km) | Number of unique indexes |

|---------------|-----------------------------|----------------------------------|--------------------------|

| 0 | 4,250,546.8477000 | 1,107.712591000 | 122 |

| 1 | 607,220.9782429 | 418.676005500 | 842 |

| 2 | 86,745.8540347 | 158.244655800 | 5,882 |

| 3 | 12,392.2648621 | 59.810857940 | 41,162 |

| 4 | 1,770.3235517 | 22.606379400 | 288,122 |

| 5 | 252.9033645 | 8.544408276 | 2,016,842 |

| 6 | 36.1290521 |3.229482772 | 14,117,882 |

| 7 | 5.1612932 | 1.220629759 | 98,825,162 |

| 8 | 0.7373276 | 0.461354684 | 691,776,122 |

| 9 | 0.1053325 | 0.174375668 | 4,842,432,842 |

| 10 | 0.0150475 | 0.065907807 | 33,897,029,882 |

| 11 | 0.0021496 | 0.024910561 | 237,279,209,162 |

| 12 | 0.0003071 | 0.009415526 | 1,660,954,464,122 |

| 13 | 0.0000439 | 0.003559893 | 11,626,681,248,842 |

| 14 | 0.0000063 | 0.001348575 | 81,386,768,741,882 |

| 15 | 0.0000009 | 0.000509713 | 569,707,381,193,162 |