ST_SquareGrid (and others) don't support points on input

[tobwen]

current situation

Currently, ST_SquareGrid (and similar functions) only supports polygons as input. When using points, there's neither any output nor a warning.

suggestion

In many cases, it's useful to generate a grid, which is based on a point.

current workaround

Buffer the point a little bit.

 SELECT * FROM ST_SquareGrid(1E1, ST_Buffer(ST_SetSRID(ST_MakePoint(12345, 54321), 3857), 1E-11));

[pramsey]

ST_Expand is a more efficient workaround.

[pramsey]

The input geometry is really just a bounds to fill. A point has no area in its bounds, so the function naturally returns nothing.

/* quick opt-out if we get nonsensical inputs  */
if (size <= 0.0 || gbounds_is_empty ||
    bounds_width <= 0.0 || bounds_height <= 0.0)
{
    funcctx = SRF_PERCALL_SETUP();
    SRF_RETURN_DONE(funcctx);
}

[Paul Ramsey <pramsey@…>]

In d1a410a/git:

Allows points to drive the generation of a single grid or square, closes #4788

[Darafei Praliaskouski <me@…>]

In fa9e07d/git:

Remove unused variable

CI Fix
References #4788