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Transforms -- from SEQNUM ​

All seqnum_to_* functions take a sequential cell index (UBIGINT) and a resolution integer.

seqnum_to_geo ​

Signatures ​

sql
GEOMETRY seqnum_to_geo (seqnum UBIGINT, res INTEGER)
GEOMETRY seqnum_to_geo (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Returns the geographic centre of the cell as a GEOMETRY POINT (longitude as x, latitude as y).

Example ​

sql
SELECT seqnum_to_geo(2380, 5);
-- → POINT (-0.902 -0.000)

seqnum_to_boundary ​

Signatures ​

sql
GEOMETRY seqnum_to_boundary (seqnum UBIGINT, res INTEGER)
GEOMETRY seqnum_to_boundary (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Returns the cell boundary as a GEOMETRY POLYGON. The exterior ring is closed (first vertex repeated). For hexagon grids, the ring contains 7 points.

Requires the spatial extension for display.

Example ​

sql
LOAD spatial;
SELECT seqnum_to_boundary(2380, 5);
-- → POLYGON ((...))

seqnum_to_seqnum ​

Signatures ​

sql
UBIGINT seqnum_to_seqnum (seqnum UBIGINT, res INTEGER)
UBIGINT seqnum_to_seqnum (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Round-trip validation: re-encodes a cell index. For valid inputs, returns the same value.

Example ​

sql
SELECT seqnum_to_seqnum(2380, 5);
-- → 2380

seqnum_to_q2di ​

Signatures ​

sql
STRUCT(quad UBIGINT, i BIGINT, j BIGINT) seqnum_to_q2di (seqnum UBIGINT, res INTEGER)
STRUCT(quad UBIGINT, i BIGINT, j BIGINT) seqnum_to_q2di (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Converts a sequential cell index to its Q2DI representation.

Example ​

sql
SELECT seqnum_to_q2di(2380, 5);
-- → {'quad': 3, 'i': 10, 'j': 10}

seqnum_to_q2dd ​

Signatures ​

sql
STRUCT(quad UBIGINT, x DOUBLE, y DOUBLE) seqnum_to_q2dd (seqnum UBIGINT, res INTEGER)
STRUCT(quad UBIGINT, x DOUBLE, y DOUBLE) seqnum_to_q2dd (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Converts a sequential cell index to its Q2DD representation.

Example ​

sql
SELECT seqnum_to_q2dd(2380, 5);
-- → {'quad': 3, 'x': 0.156, 'y': 0.271}

seqnum_to_projtri ​

Signatures ​

sql
STRUCT(tnum UBIGINT, x DOUBLE, y DOUBLE) seqnum_to_projtri (seqnum UBIGINT, res INTEGER)
STRUCT(tnum UBIGINT, x DOUBLE, y DOUBLE) seqnum_to_projtri (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Converts a sequential cell index to its PROJTRI representation.

Example ​

sql
SELECT seqnum_to_projtri(2380, 5);
-- → {'tnum': 7, 'x': 0.688, 'y': 0.0}

seqnum_to_plane ​

Signatures ​

sql
STRUCT(x DOUBLE, y DOUBLE) seqnum_to_plane (seqnum UBIGINT, res INTEGER)
STRUCT(x DOUBLE, y DOUBLE) seqnum_to_plane (seqnum UBIGINT, res INTEGER, params STRUCT)

Description ​

Converts a sequential cell index to unfolded icosahedron plane coordinates.

Example ​

sql
SELECT seqnum_to_plane(2380, 5);
-- → {'x': 2.313, 'y': 1.732}