duck_dggs

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Grid Statistics ​

These functions return grid statistics for a given resolution without requiring a cell identifier.

dggs_n_cells ​

Signatures ​

sql
UBIGINT dggs_n_cells (res INTEGER)
UBIGINT dggs_n_cells (res INTEGER, params STRUCT)

Description ​

Returns the total number of cells at the given resolution.

Example ​

sql
SELECT dggs_n_cells(5);
┌─────────────────┐
│ dggs_n_cells(5) │
│     uint64      │
├─────────────────┤
│           10242 │
└─────────────────┘

dggs_cell_area_km ​

Signatures ​

sql
DOUBLE dggs_cell_area_km (res INTEGER)
DOUBLE dggs_cell_area_km (res INTEGER, params STRUCT)

Description ​

Returns the average cell area in km² at the given resolution.

Example ​

sql
SELECT dggs_cell_area_km(5);
┌──────────────────────┐
│ dggs_cell_area_km(5) │
│        double        │
├──────────────────────┤
│   49811.09587149303  │
└──────────────────────┘

dggs_cell_dist_km ​

Signatures ​

sql
DOUBLE dggs_cell_dist_km (res INTEGER)
DOUBLE dggs_cell_dist_km (res INTEGER, params STRUCT)

Description ​

Returns the average cell spacing (distance between cell centres) in km at the given resolution.

Example ​

sql
SELECT dggs_cell_dist_km(5);
┌──────────────────────┐
│ dggs_cell_dist_km(5) │
│        double        │
├──────────────────────┤
│   220.4266384815885  │
└──────────────────────┘

dggs_cls_km ​

Signatures ​

sql
DOUBLE dggs_cls_km (res INTEGER)
DOUBLE dggs_cls_km (res INTEGER, params STRUCT)

Description ​

Returns the characteristic length scale (CLS) in km at the given resolution.

Example ​

sql
SELECT dggs_cls_km(5);
┌────────────────────┐
│   dggs_cls_km(5)   │
│       double       │
├────────────────────┤
│ 251.84027008853553 │
└────────────────────┘

dggs_res_info ​

Signatures ​

sql
STRUCT dggs_res_info (res INTEGER)
STRUCT dggs_res_info (res INTEGER, params STRUCT)

Return type: STRUCT(res INTEGER, cells UBIGINT, area_km DOUBLE, spacing_km DOUBLE, cls_km DOUBLE)

Description ​

Returns all grid statistics for the given resolution as a single struct.

Example ​

sql
SELECT dggs_res_info(5);
┌────────────────────────────────────────────────────────────────────────────────────┐
│                                 dggs_res_info(5)                                   │
│      struct(res integer, cells ubigint, area_km double, ...)                       │
├────────────────────────────────────────────────────────────────────────────────────┤
│ {res: 5, cells: 10242, area_km: 49811.1, spacing_km: 220.4, cls_km: 251.8}        │
└────────────────────────────────────────────────────────────────────────────────────┘