[postgis-devel] Tiger to PostGIS Topology looking much better now

Paragon Corporation lr at pcorp.us
Fri Sep 9 22:09:09 PDT 2011

Andrea and strk,

I figured out where I went wrong with my final 25 errors so I think I'm in
good shape now.  In my import I was missing some edges in some faces
where the face does not completely fall in my region of interest. 

After fixing that I no longer get any topology validation errors and my
viewing of face geometries looks like what I would expect.

So in short all my topology validation errors can be reduced down to two
1) tolerance issues -- about 400 some odd failures because of that which
were solved by snapping points to a reasonable
 tolerance before load (not too big or small)
2) the fact I had logical error in my query designed to pull remaining edges
of faces not covered in my area of interest)

Now for the fun part of loading topo geometries.  Is there an easier way
aside from specifying the element array stuff.

Ideally would be nice to have a function where you pass in a regular
geometry and it converts it to a topogeometry.

This is mostly for loading denormalized features such as the tiger features
that you know were formed from a topology.
It would throw an error if the edges don't line up.


> -----Original Message-----
> From: postgis-devel-bounces at postgis.refractions.net 
> [mailto:postgis-devel-bounces at postgis.refractions.net] On 
> Behalf Of PostGIS
> Sent: Friday, September 09, 2011 4:55 PM
> Cc: postgis-devel at postgis.refractions.net
> Subject: Re: [postgis-devel] [PostGIS] #1181: 
> topology.TopologySummary isbroken
> #1181: topology.TopologySummary is broken
> -----------------------+--------------------------------------
> ----------
> -----------------------+----
>   Reporter:  robe      |       Owner:  strk         
>       Type:  defect    |      Status:  closed       
>   Priority:  critical  |   Milestone:  PostGIS 2.0.0
>  Component:  topology  |     Version:  trunk        
> Resolution:  fixed     |    Keywords:               
> -----------------------+--------------------------------------
> ----------
> -----------------------+----
> Comment(by aperi2007):
>  Hi,
>  Robe,
>  I don't know your tiger dataset.
>  You are using the topology ISO functions ?
>  Or try to load directly in the tables ?
>  If you use the ISO function you should not see happened that 
>  validatetopology error. The ISO function should directly 
> lock any try to  insert a wrong edge.
> --
> Ticket URL: <http://trac.osgeo.org/postgis/ticket/1181#comment:5>
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