Incorrect result of SDO_ANYINTERACT query under WGS84

Question

I have just import a country shapefile into oracle sptial with WGS spatial reference(srid is 8307 in oracle spatial) using shp2ora.
The layer contains the data of the countries in the world. And the spatial extent of that layer is -180,180,-90,90.
After importing, I built the R-tree index on that table.
When i used SDO_ANYINTERACT to query the layer, the result was incorrect. The SQL was
SELECT COUNT(*) FROM country WHERE SDO_ANYINTERACT(shape,SDO_GEOMETRY('POLYGON((-170 -80,-170 80,170 80,170 -80,-170 -80))',8307))='TRUE';
The result is 4. But the extent almost covers the whole world, the correct answer should be more than 100.
But, if I set the srid is NULL, then the above sql can return the correct answer.
So. anyone knows how to use the SDO_ANYINTERACT operator under the spatial reference WGS84??

Answer 1

Hi,
Your geodetic polygon is too big ( >= half of the earth surface), as a result, the result might not be correct.
This is documented in Oracle Spatial manual (11.2).
6.2.5 Other Considerations and Requirements with Geodetic Data
The following size limits apply with geodetic data:
No polygon element can have an area larger than or equal to one-half the surface of the Earth. Moreover, if the result of a union of two polygons is greater than one-half the surface of the Earth, the operation will not produce a correct result. For example, if A union B results in a polygon that is greater than one-half of the area of the Earth, the operations A difference B, A intersection B, and A XOR B are not supported, and only a relate operation with the ANYINTERACT mask is supported between those two polygons.
In a line, the distance between two adjacent coordinates cannot be greater than or equal to one-half the perimeter (a great circle) of the Earth.
If you need to work with larger elements, first break these elements into multiple smaller elements and work with them. For example, you cannot create a geometry representing the entire ocean surface of the Earth; however, you can create multiple geometries, each representing part of the overall ocean surface. To work with a line string that is greater than or equal to one-half the perimeter of the Earth, you can add one or more intermediate points on the line so that all adjacent coordinates are less than one-half the perimeter of the Earth.
You might have to break the polygon into smaller ones.
For projected coordinate systems, there is no such limitation.
jack