[osmosis-dev] one node ways

[Jochen Topf]

You can have several nodes on the same position which could also lead to a
broken geometry but will not be caught be looking just at the nodes.

Jochen

On Sat, Apr 09, 2011 at 02:22:58PM +0400, Kirill Bestoujev wrote:
> Date: Sat, 9 Apr 2011 14:22:58 +0400
> From: Kirill Bestoujev <bestoujev at gmail.com>
> To: osmosis-dev at openstreetmap.org
> Subject: Re: [osmosis-dev] one node ways
> 
> And in works!
> 
> and (select count(1) from (select n.geom as geom, count(1) as node_count
> from way_nodes wn join nodes n on n.id = wn.node_id where wn.way_id =
> w.idgroup by 1) n_group) > 1
> 
> added to the request below works fine!
> 
> I will look at it for a couple of days to make sure it works in all cases,
> but looks like it is a solution.
> 
> What is the process of merging it into osmosis distro?
> 
> The pg_snapshot and pg_simple load scripts   should also be updated!
> 
> Kirill
> 
> 2011/4/9 Kirill Bestoujev <bestoujev at gmail.com>
> 
> > Sure, I know this. But if I create an indes with, for example, a st_within
> > condition, than osmosis falls already while replicating diffs...
> >
> > That's why I want to solve the problem in osmosis itself, not in the db.
> >
> > Yesterday on Russian irc channel we found a solution to add to NodeDao.java
> > linesting update sql-command the following line:
> >
> > and (select count(1) from (select n.geom as geom, count(1) as node_count
> > from way_nodes wn join nodes n on n.id = wn.node_id where wn.way_id = w.idgroup by 1) n_group) > 1
> >
> > This solves the problem with ways having only duplicate nodes in them.
> >
> > But the recompiled version of osmosis falls on the following command:
> >
> > org.springframework.jdbc.
> > UncategorizedSQLException: PreparedStatementCallback; uncategorized
> > SQLException for SQL [UPDATE ways w SET linestring = ( SELECT
> > MakeLine(c.geom) AS way_line FROM ( SELECT n.geom AS geom FROM nodes n INNER
> > JOIN way_nodes wn ON n.id = wn.node_id WHERE (wn.way_id = w.id) and
> > array_length(nodes, 1) > 1 ORDER BY wn.sequence_id ) c ) WHERE w.id  = ?];
> > SQL state [XX000]; error code [0]; ERROR: Exception in LWGEOM2GEOS; nested
> > exception is org.postgresql.util.PSQLException: ERROR: Exception in
> > LWGEOM2GEOS
> >
> > the added code - and array_length(nodes, 1) > 1 - which I thought was
> > solving the problem does not work OR there is an other problem - not one
> > node ways.
> >
> > Kirill
> >
> >
> > 2011/4/9 Jochen Topf <jochen at remote.org>
> >
> >> Hi!
> >>
> >> This has worked for me: I use the ST_isvalid() function in Postgis to find
> >> out
> >> if a geometry is valid. If not, I either delete the way or set the
> >> geometry to
> >> NULL and then do all further processing only on ways with geometry !=
> >> NULL.
> >>
> >> Jochen
> >>
> >> On Fri, Apr 08, 2011 at 08:55:43PM +0400, Kirill Bestoujev wrote:
> >> > Date: Fri, 8 Apr 2011 20:55:43 +0400
> >> > From: Kirill Bestoujev <bestoujev at gmail.com>
> >> > To: Igor Podolskiy <igor.podolskiy at vwi-stuttgart.de>
> >> > Cc: osmosis-dev <osmosis-dev at openstreetmap.org>
> >> > Subject: Re: [osmosis-dev] one node ways
> >> >
> >> > Igor,
> >> >
> >> > the context is simple - we have a mirror of the planet, we update if
> >> with
> >> > replication with minute diffs.
> >> >
> >> > You may have a look at way 35966868 to see the problem by yourself.
> >> After
> >> > creation of geom by osmosis it looks like LINESTRING(2.2321042
> >> > 48.7767191,2.2321042 48.7767191) which is not good.
> >> >
> >> >
> >> >
> >> > K.
> >> >
> >> > 2011/4/8 Igor Podolskiy <igor.podolskiy at vwi-stuttgart.de>
> >> >
> >> > > Hi Kirill,
> >> > >
> >> > >
> >> > >  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.
> >> > >>
> >> > >
> >> > > I think I understand the problem but I'm having a hard time
> >> understanding
> >> > > the context :) Could you maybe provide a simple example and/or a
> >> > > step-by-step guide to reproduce this? Like the osmosis command line
> >> you're
> >> > > using, the kind of data you're trying to put in the database - that
> >> would be
> >> > > very helpful.
> >> > >
> >> > > Regards
> >> > > Igor
> >> > >
> >>
> >> > _______________________________________________
> >> > osmosis-dev mailing list
> >> > osmosis-dev at openstreetmap.org
> >> > http://lists.openstreetmap.org/listinfo/osmosis-dev
> >>
> >>
> >> --
> >> Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/ +49-721-388298
> >>
> >>
> >

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-- 
Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298