[postgis-users] TopologyException: geom is invalid

[Joseph Spenner]

I ran the following against all 4 of my GeoJSON files:
SELECT ST_IsSimple(ST_GeomFromGeoJSON('@poly'))SELECT ST_IsValid(ST_GeomFromGeoJSON('@poly'))SELECT ST_IsValidDetail(ST_GeomFromGeoJSON('@poly'))SELECT ST_IsValidReason(ST_GeomFromGeoJSON('@poly'))
where @poly contained each one of the following:
http://microflush.org/stuff/json/MN.jsonhttp://microflush.org/stuff/json/mnz091.json
http://microflush.org/stuff/json/CA.jsonhttp://microflush.org/stuff/json/nwsZone.json

The select returned no error.  I tried to vary the input slightly to make sure I was using the proper syntax, and was able to get errors-- such as:
DBD::Pg::st execute failed: ERROR:  geometry contains non-closed rings

So, it would seem my geoms are ok.
I've not yet tried the "ST_MakeValid".   But wouldn't the above indicate they're already valid?
Thanks!





      From: Joseph Spenner <joseph85750 at yahoo.com>
 To: PostGIS Users Discussion <postgis-users at lists.osgeo.org> 
 Sent: Thursday, February 26, 2015 8:05 AM
 Subject: Re: [postgis-users] TopologyException: geom is invalid
   
Hello, and thanks for the replies!I'll try those suggestions.
Just curiuos though-- which geometry seems to be invalid?  Is it the state poly, or the smaller county/zone poly?  If there was an invalid geometry, wouldn't it always show up for that state or county?  Here's what I observed for the CA issue:
1) I had 3 smaller county poly/geometries in CA.  When performing my query, instead of returning the 3 polys, I received the error which I posted in my original thread.  I identified it was 1 of those 3.  I deleted that 1 offending geometry from my table.  After doing so, my query against CA turned up the remaining 2, with no errors.  So, that leads me to believe CA is ok.  Or is this not a valid assumption?   Perhaps the location where that offending intersection would have occurred in the CA poly has an issue, and it doesn't get tickled unless the smaller county zone intersects it?
2) I was able to plot the offending county described above in the GeoJSONLint validation page:   http://geojsonlint.com/  There didn't appear to be any issues.
Thanks!
Regards,Joseph Spenner



  


 

     From: Rémi Cura <remi.cura at gmail.com>
 To: PostGIS Users Discussion <postgis-users at lists.osgeo.org> 
Cc: Joseph Spenner <joseph85750 at yahoo.com> 
 Sent: Thursday, February 26, 2015 1:28 AM
 Subject: Re: [postgis-users] TopologyException: geom is invalid
   
And also ST_IsSimple (that precisely check for self intersection).
Cheers,
Rémi-C

2015-02-26 8:32 GMT+01:00 BladeOfLight16 <bladeoflight16 at gmail.com>:



On Wed, Feb 25, 2015 at 12:14 PM, Joseph Spenner <joseph85750 at yahoo.com> wrote:

DBD::Pg::st execute failed: ERROR:  Error performing intersection: TopologyException: Input geom 1 is invalid: Self-intersection at or near point -381688.06935935974 -1206669.4272876547 at -381688.06935935974 -1206669.4272876547 at ./test.pl line 151.


Did you try ST_IsValid to verify the geometry is valid according to the OGC standard? (See http://postgis.net/docs/using_postgis_dbmanagement.html#OGC_Validity. ST_IsValidDetail and ST_IsValidReason are also helpful in this regard.) What happens if you run it through ST_MakeValid? Be aware that ST_MakeValid can sometimes result in GeometryCollections if the input shape is malformed (usually "rings" without enough points are that have different start and end points).

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