Question

Oracle Geometry Validation


Hi,

 

 

I was wondering could anyone help me with a problem that I am having with Oracle Geometry Validation.  I initially got an Oracle Dmp file containin a polygon dataset which have a Tolerance of 0.0005 and Irish National Grid 29900, I have implemented the Oracle Geometry Validation with the Tolerance check of 0.0005 and all features have validated with no issues.  

 

 

The Oracle spatial dataset was then transformed into an ESRI SDE Feature Class within a Feature Dataset which uses the Irish National Grid spatial 29902 reference system with all the standard defaults used i.e. x,y tolerance 0.001 and x,y resolution 0.0001.  All features loaded successfully into this feature class.

 

 

The data was then exported to an Oracle dmp file and provided to another person who imported the data into their Oracle database and into their Database Schema.

 

 

I was asked to analysis on the new schema so therefore the data was provided back to me as an Oracle dmp file, I implemented the Oracle Validation as I did before but this time it is returning Errors 13349 and 13356, no edits have been made to this dataset so I can't understand why there are errors being returned.  Anybodys help and advice on this would be great. Thanks

 

 

4 replies

Userlevel 4
Hi

 

 

as far as I can tell, those two errors indicates self-intersecting polygons and duplicate vertices. It was probably introduced by rounding errors when importing and exporting the data between two different systems. Also be aware that when writing data to an ESRI database, all the vertices will be snapped to the tolerance grid that is not only defined by the tolerance setting, but also by the dataset extent (domain).

 

 

Explicit or implicit reprojections during import/export can also introduce slight shifts in the data that can cause problems, e.g. the coordinate system defintions might in some cases differ very slightly between the systems.

 

 

You can fix both these issues using the GeometryValidator in FME.

 

 

David

 

 
Hi David, Many thanks for getting back to me in relation to my query below. I tried translating the Oracle data to an Esri SDE Feature Class within a Feature Dataset which used the Irish National Grid Spatial 29902 reference system with the x,y tolerance set to 0.0005 and the x,y resolution as 0.0025 but it returned the same issues. Do you know if this is a common issue when translating data? Or is there any way to stop the rounding of co-ordinates? Many thanks Andrea
Userlevel 4
Hi

 

 

in my experience this is a common issue when moving geometries (in particular complex polygons) between different spatial databases and/or coordinate systems.

 

 

Some transformers that could be part of a solution include
  • GeometryValidator
  • CoordinateRounder
  • ArcSDEGridSnapper (when writing to ArcSDE only)
  • Snapper / AnchoredSnapper
David
Hi David, Many thanks for your help with my query. Andrea

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