[postgis-users] st_union() - a dumb question

[Chris Hermansen]

Good people, I have a dumb question.  Yes it's really a dumb question.

To accompany the dumb question, I have a dumb illustration that will
definitely look really dumb unless viewed with a fixed-width font.

Let's say I have three somewhat coincident lines.  Specifically, let's
say they're precisely colinear, and "from the side", they look like this:

A --------------------------------------
B         --------------------------------------------------
C    ----------------------------------------------

What I'm wondering is, if I st_union() them together, should I expect as
a result a linestring composed of five shorter segments that looks like
this?  Or alternatively, maybe a bunch of short lines, or maybe a
multilinestring?

U ---+----+----------------------------+----------+---------

In other words, with "nodes" where there were endpoints of the input lines?

-- 
Regards,

Chris Hermansen · mailto:clh at timberline.ca
tel:+1.604.714.2878 · fax:+1.604.733.0631
Timberline Natural Resource Group · http://www.timberline.ca
401 · 958 West 8th Avenue · Vancouver BC · Canada · V5Z 1E5

C'est ma façon de parler.