1.12 H3 Indexing

Oracle Spatial provides support for hexagonal hierarchical spatial indexing (H3) in Oracle Database.

H3 is an open source indexing system developed by Uber that uses hexagons in a grid system to cover the earth’s surface. Data points are bucketed in hexagon cells, and attributes can be aggregated and summarized over these hexagons. For very large volumes of point data, H3 cells are very useful to visualize aggregated attribute data in thematic maps.

Oracle Spatial H3 support includes several functions in the database to generate H3 cells from point data. Additionally, functions are provided to directly generate vector tiles from the aggregated H3 data. These vector tiles can be shared with web clients to create map visualizations.

Hexagonal indexing is translating a point in geodetic (longitude, latitude) coordinate system to a space defined by sphere circumscribed Icosahedron (polygon with 20 faces) approximation of Earth, which essentially is a grid of hexagons (also a few pentagon special cases). H3 index comprises 16 such grids, arranged in a hierarchy. The level 0 grid contains 122 hexagons (110 hexagons, 12 pentagons).

The following functions in the SDO_UTIL package provides H3 indexing support for spatial data in Oracle Database:

• SDO_UTIL.H3SUM_CREATE_TABLE
• SDO_UTIL.H3SUM_VECTORTILE
• SDO_UTIL.H3_KEY
• SDO_UTIL.H3SUM_AS_TABLE
• SDO_UTIL.H3_MBR
• SDO_UTIL.H3_PENTAGON_EDGELEN
• SDO_UTIL.H3_HEX_EDGELEN
• SDO_UTIL.H3_BASE_CELL
• SDO_UTIL.H3SUM_GET_CURSOR
• SDO_UTIL.H3_RESOLUTION
• SDO_UTIL.H3_PARENT
• SDO_UTIL.H3_IS_CLASS3
• SDO_UTIL.H3_PENTAGON_AREA
• SDO_UTIL.H3_NUM_CELLS
• SDO_UTIL.H3_HEX_AREA
• SDO_UTIL.H3_CENTER
• SDO_UTIL.H3_BOUNDARY