duck_dggs

Appearance

Transforms -- from PROJTRI ​

All projtri_to_* functions take an icosahedron triangle number (UBIGINT), continuous x and y coordinates (DOUBLE), and a resolution integer.

projtri_to_geo ​

Signatures ​

sql
GEOMETRY projtri_to_geo (tnum UBIGINT, x DOUBLE, y DOUBLE, res INTEGER)
GEOMETRY projtri_to_geo (tnum UBIGINT, x DOUBLE, y DOUBLE, res INTEGER, params STRUCT)

Description ​

Returns the geographic centre of the nearest DGGS cell as a GEOMETRY POINT.

Example ​

sql
SELECT projtri_to_geo(7, 0.6875, 0.0, 5);
-- → POINT (-0.902 -0.000)

projtri_to_seqnum ​

Signatures ​

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

Description ​

Converts a PROJTRI coordinate to the corresponding sequential cell index.

Example ​

sql
SELECT projtri_to_seqnum(7, 0.6875, 0.0, 5);
-- → 2380

projtri_to_q2di ​

Signatures ​

sql
STRUCT(quad UBIGINT, i BIGINT, j BIGINT) projtri_to_q2di (tnum UBIGINT, x DOUBLE, y DOUBLE, res INTEGER)
STRUCT(quad UBIGINT, i BIGINT, j BIGINT) projtri_to_q2di (tnum UBIGINT, x DOUBLE, y DOUBLE, res INTEGER, params STRUCT)

Description ​

Converts a PROJTRI coordinate to Q2DI (quad number + integer i/j indices).

Example ​

sql
SELECT projtri_to_q2di(7, 0.6875, 0.0, 5);
-- → {'quad': 3, 'i': 10, 'j': 10}

projtri_to_q2dd ​

Signatures ​

sql
STRUCT(quad UBIGINT, x DOUBLE, y DOUBLE) projtri_to_q2dd (tnum UBIGINT, x DOUBLE, y DOUBLE, res INTEGER)
STRUCT(quad UBIGINT, x DOUBLE, y DOUBLE) projtri_to_q2dd (tnum UBIGINT, x DOUBLE, y DOUBLE, res INTEGER, params STRUCT)

Description ​

Converts a PROJTRI coordinate to Q2DD (quad number + continuous x/y).

Example ​

sql
SELECT projtri_to_q2dd(7, 0.6875, 0.0, 5);
-- → {'quad': 3, 'x': 0.156, 'y': 0.271}

projtri_to_projtri ​

Signatures ​

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

Description ​

Re-encodes a PROJTRI coordinate through a full round-trip.

Example ​

sql
SELECT projtri_to_projtri(7, 0.6875, 0.0, 5);
-- → {'tnum': 7, 'x': 0.688, 'y': 0.0}

projtri_to_plane ​

Signatures ​

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

Description ​

Converts a PROJTRI coordinate to unfolded icosahedron plane coordinates.

Example ​

sql
SELECT projtri_to_plane(7, 0.6875, 0.0, 5);
-- → {'x': 2.313, 'y': 1.732}