ST_Affine

Introduction: Apply an affine transformation to the given geometry.

ST_Affine has 2 overloaded signatures:

ST_Affine(geometry, a, b, c, d, e, f, g, h, i, xOff, yOff, zOff)

ST_Affine(geometry, a, b, d, e, xOff, yOff)

Based on the invoked function, the following transformation is applied:

x = a * x + b * y + c * z + xOff OR x = a * x + b * y + xOff

y = d * x + e * y + f * z + yOff OR y = d * x + e * y + yOff

z = g * x + f * y + i * z + zOff OR z = g * x + f * y + zOff

If the given geometry is empty, the result is also empty.

Format:

ST_Affine(geometry, a, b, c, d, e, f, g, h, i, xOff, yOff, zOff)

ST_Affine(geometry, a, b, d, e, xOff, yOff)

Since: v1.5.0

Examples:

ST_Affine(geometry, 1, 2, 4, 1, 1, 2, 3, 2, 5, 4, 8, 3)

Input: LINESTRING EMPTY

Output: LINESTRING EMPTY

Input: POLYGON ((1 0 1, 1 1 1, 2 2 2, 1 0 1))

Output: POLYGON Z((9 11 11, 11 12 13, 18 16 23, 9 11 11))

Input: POLYGON ((1 0, 1 1, 2 1, 2 0, 1 0), (1 0.5, 1 0.75, 1.5 0.75, 1.5 0.5, 1 0.5))

Output: POLYGON((5 9, 7 10, 8 11, 6 10, 5 9), (6 9.5, 6.5 9.75, 7 10.25, 6.5 10, 6 9.5))

ST_Affine(geometry, 1, 2, 1, 2, 1, 2)

Input: POLYGON EMPTY

Output: POLYGON EMPTY

Input: GEOMETRYCOLLECTION (MULTIPOLYGON (((1 0, 1 1, 2 1, 2 0, 1 0), (1 0.5, 1 0.75, 1.5 0.75, 1.5 0.5, 1 0.5)), ((5 0, 5 5, 7 5, 7 0, 5 0))), POINT (10 10))

Output: GEOMETRYCOLLECTION (MULTIPOLYGON (((2 3, 4 5, 5 6, 3 4, 2 3), (3 4, 3.5 4.5, 4 5, 3.5 4.5, 3 4)), ((6 7, 16 17, 18 19, 8 9, 6 7))), POINT (31 32))

Input: POLYGON ((1 0 1, 1 1 1, 2 2 2, 1 0 1))

Output: POLYGON Z((2 3 1, 4 5 1, 7 8 2, 2 3 1))