[PostGIS] #5776: ST_LineSubstring 3D support

[PostGIS]

#5776: ST_LineSubstring 3D support
---------------------+---------------------------
 Reporter:  vla123   |      Owner:  pramsey
     Type:  defect   |     Status:  new
 Priority:  medium   |  Milestone:  PostGIS 3.4.3
Component:  postgis  |    Version:  3.4.x
 Keywords:           |
---------------------+---------------------------
 It seems that ST_LineSubstring function return wrong results for 3D
 linestrings.


 {{{
 select
         st_3dlength(geometry) as full_line ,
         st_3dlength(st_linesubstring(geometry, 0.0, 0.50)) as half_line
 from (
                 select st_makeline(ARRAY[
                 st_setsrid(st_pointz(0,0,0), 3857),
                 st_setsrid(st_pointz(0,2,5), 3857),
                 st_setsrid(st_pointz(0,10,10), 3857)
                 ]) as geometry
         ) line

 Output :

 "full_line"     "half_line"
 14.819145939191106      8.92290773165573
 }}}

 This should be explicitly stated on
 [https://postgis.net/docs/ST_LineSubstring.html documentation].
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5776>
PostGIS <http://trac.osgeo.org/postgis/>
The PostGIS Trac is used for bug, enhancement & task tracking, a user and developer wiki, and a view into the subversion code repository of PostGIS project.