Interpolate points along a line: add a fixed distance version

[pcav]

Currently, ST_LineInterpolatePoint accepts a proportion as a parameter. Often users want them at fixed intervals (e.g. every km). It would be useful to have then a different version of this command, accepting a fixed distance and create a variable number of points according to it.

[strk]

It would need a good name, how about ST_InterpolatePointsAtDistance ?

[dbaston]

Is this different from ST_Segmentize?

[strk]

Daniel: it returns points interpolated along a line at fixed consecutive distance. As a multipoint (I guess), and won't necessarely include the original line vertices.

[strk]

ST_InterpolatedPoints would seem a good name to me.

[robe]

are we still planning to have this for 2.4, if not it should be done within the next week. If not push to future.

[dbaston]

What about a function ST_LineInterpolatePoints that is the same as ST_LineInterpolatePoint, except that it repeats the proportion as many times as possible and returns a MultiPoint.

So, where ST_LineInterpolatePoint(geom, 0.2) would return a single point, ST_LineInterpolatePoints(geom, 0.2) would return points at and 0.2, 0.4, 0.6, 0.8, 1.0. ST_LineInterpolatePoints(geom, 0.3) would return points at 0.3, 0.6, 0.9.

If a user wants to specify a distance rather than a proportion, it would be trivial to do ST_LineInterpolatePoints(geom, dist / ST_Length(geom))

[dbaston]

In 15913:

Add ST_LineInterpolatePoints

Closes #3564