[postgis-devel] LRS Functions

[Paul Ramsey]

Thus far, we have very few LRS functions (well, one).

line_interpolate_point(geometry, proportion)

     Interpolates a point along a line. First argument must be a
     LINESTRING. Second argument is a float between 0 and 1.
     Returns a point.

This is OK, but we need two more:

line_calculate_proportion(line, point)

     Returns a float, representing the proportional distance the
     point is located along the line.

line_interpolate_line(geometry, proportion, direction)

     Returns a line, representing the subset of the input line
     that is the proportional distance along the line. Direction
     determines what end to measure from. (??)