EF5几何相交查询不返回任何内容

Question

I have a SQL Server 2008 R2 table which has a geometry (not geography) column, as well as some other "standard" columns. I currently have a single row in the table for testing, and the geometry column in that record has a polygon with the following bounds, and the SRID when I inserted the polygon was 0 (zero):

POLYGON ((380 220, 380 575, 585 575, 380 575, 380 220))

I now want to check to see if a point is in that polygon, using EF5. First I create the point:

DbGeometry testPoint = DbGeometry.PointFromText("POINT(400 240)", 0);

List<LocationArea> tResults = (from s in db.LocationAreas
       where testPoint .Intersects(SqlSpatialFunctions.MakeValid(s.AreaBounds))
       select s).ToList();

The first error I got, before adding the SqlSpatialFunctions.MakeValid method was that the s.AreaBounds result was not "valid", whilst the point created in code was. Fixed that one with the help of this excellent post -> query-dbgeometry-for-specific-latlng-value

Now, I could be going crazy (I've been looking at this code for a while), however I always get an empty list returned (count = 0), and I believe the point is within the polygon bounds.

So, any pointers would be appreciated, like I said though, could just be me :-)

Dominik

Answer 1

After trying many, many different things to get the result I wanted, the code below now finally works, and works every time, with every polygon / point scenario I have thrown at it so far.

Why this is required I do not know, but I certainly hope this helps someone else in future when using geometry SQL columns with Entity Framework:

DbGeometry testPoint = DbGeometry.PointFromText("POINT(400 240)", 0);

List<LocationArea> tResults = (from s in db.LocationAreas
   where testPoint .Intersects(SqlSpatialFunctions.MakeValid(s.AreaBounds).Envelope)
   select s).ToList();

I found this after some in-depth debugging and really going through the DBGeometry field returned via the Linq query. I found that the s.AreaBounds field returned a LINESTRING(...) value instead of what was saved in the DB originally, which was a POLYGON(...) value. Looking further through the returned object properties I found that .Envelope had what I wanted.