gis.geos.GEOSGeometry.project_normalized()

GEOSGeometry.project_normalized(point)

Returns the distance (float) from the origin of the geometry (LineString or MultiLineString) to the point projected on the geometry (that is to a point of the line the closest to the given point). The normalized version returns the distance as a float between 0 (origin) and 1 (endpoint).

Reverse of GEOSGeometry.interpolate().