A number of linear referencing functions will be developed in this chapter. These functions will draw upon or extend functions presented in the previous chapters, most notably ST_Split and ST_Snap. A recap of what these do follows:
ST_Split: Splits a linestring at one or more known points placed on or off the line.
ST_Snap: Snaps (projects) a known point onto a linestring to determine its measure (or length) from beginning.
The following list outlines those linear referencing functions that will be implemented:
ST_Find_Measure: Given a point near a measured linestring, return the nearest measure.
ST_Scale_Measures: Rescales the measures of a linestring and optionally applies an offset. Thus an existing measured linestring whose measure starts at 0 m and finishes at 100 m may be changed to start at 5 m (offset) and end at 106.5 m (rescale).ST_Add_Measure: Takes an existing unmeasured linestring and a start and end measure, and returns a linestring...