[osmosis-dev] one node ways
Kirill Bestoujev
bestoujev at gmail.com
Fri Apr 8 13:12:13 BST 2011
Hi!
A couple of days ago I opened a ticket for the subject:
http://trac.openstreetmap.org/ticket/3650
The problem is the following:
When a one node way is present in the database and osmosis creates a
linestring geometry for it the resulting geometry is something like
LINESTRING(139.386972 37.095865)
When we process this linestring with any postgis function it gives us an
error - the linestring must contain 0 or > 1 nodes.
When linestring objects are created with internal osmosis functions the
number of nodes is checked to be >= 2, but the sql-command does not
contain such a check.
I suggested a solution which looked very easy and helpful, but when I
compiled osmosis with the proposed changed I found out that the problem
is solved only partially - the creation of new linestring we one node is
gone, but the creation (and update) of linestring with two (3, 4)
duplicated nodes in one position (which gives also a not valid geom) is
still there.
I am not a programmer, so I failed to find a proper modification for the
sql-command which updates the linestring - I can figure out how to check
the nodes in the same sql-request with the creation of the linestring.
The problem with invalid geoms does not let create indexes with, for
example st_within functions, which limits very much the usefulness of
the database...
Please help me with this case!
Kirill Bestoujev
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