SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION

Format

SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION(
  h3_table     IN VARCHAR2 DEFAULT NULL,
  tile_zoom    IN NUMBER,
  hexes        IN NUMBER DEFAULT NULL
) RETURN NUMBER;

Description

Provides an H3 resolution which will result in approximately the requested number of hexes in the given tile.

Parameters

h3_table

The H3 table used to get the extent of the data. If NULL, then it is assumed that the data extent is global.

tile_zoom

The zoom value. This value is mandatory.

hexes

The number of hexes required in the given tile. If NULL, then a default value of 300 is used.

Usage Notes

The SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION procedure returns a number between 0 and 15 inclusive.

Increasing or decreasing the resolution by 1 changes the number of hexes by approximately a factor of 7. Also, note that the tiles near the equator represent areas as much as 130x larger than tiles at the poles. Therefore, the actual number of hexes in a tile will vary considerably from the goal value.

Examples

The following example queries use the SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION procedure to determine the estimated H3 resolution:

SELECT SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION(tile_zoom=>7) FROM DUAL;

SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION(TILE_ZOOM=>7)
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SELECT SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION(tile_zoom=>7, hexes=>500) FROM DUAL;

SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION(500,TILE_ZOOM=>7)
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                                                   6

SELECT SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION('QUTTINIRPAAQ_H3', tile_zoom=>7, hexes=>500);


SDO_UTIL.H3SUM_ESTIMATE_RESOLUTION('QUTTINIRPAAQ_H3',TILE_ZOOM=>7,HEXES=>500)
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