Different precision between ST_Geometry SQL result and ArcGIS Server REST API result

Question

When using ST_Geometry to get the wkt or wkb from a feature class each coordinate gets rounded to 4 numbers after the decimal.

Query:
SELECT sde.st_astext(g.shape) as wkt 
FROM geodata g 
WHERE gisid in (1234)

Result:POLYGON  (( 818052.36380000 5742316.96420000,  ...)

When accessing the same feature class via REST API Query from ArcGIS Server i will get:
[
      [
       818052.3638000004,
       5742316.9641999993
      ],
...
]

Using:
- ArcGIS Server 10 SP 2 on Windows 2008 english
- ArcSDE 10 SP 2, using direct connect for all features @ mxd
- Oracle 11.2.0.3 on Windows 2008 german

Why do i get only rounded values via ST_Geometry? Is this a Oracle Issue? It it possible to alter the session to get the complete value?

Querying the same feature via ArcGIS Server REST API and ST_Geometry should return exactly the same Polygon.

Any Idea?

Stefan

StefanP__Jung · Answer

Esri was able to reproduce this issue:

NIM078128 REST JSON geometry query returns incorrect level of precision.

Stefan

VinceAngelo · Answer

The precision of an ST_GEOMETRY object is defined by its SRID.  The ST_UNION
operator should handle the merge of overlapping geometries correctly.  You should
start an incident in the ArcGIS Server REST API queue if the display precision
is causing topology problems.

- V

StefanP__Jung · Answer

My problem is that i have a service that receives a wkb/wkt polygon from a client. This polygon originally comes from The ArcGIS Server REST API. The client requests to create a union with the given wkb/wkt and a polygon which is already stored @SDE.

If both polygons touch each other the union result is "corrupted" at the common border. If the ArcGIS Server REST would return the expected values the topology of the two polygons would be ok.

The union is performed via ST_GEOMETRY, is it possible to set the precision for the UNION?

I can post some detailed information tomorrow when i am back in the office,

Stefan