LocationRect wrong values due to DateLine

Question

Im working on the Silverlight control I have a situation where I reduce polygons on the server based on the LocationRect I pass from the client. My problem is when I have the east cooridinate less than the west (dateline issues), I know its a common scenario but I haven't found the right algorithim to get the right east and west points. Can you direct me please?

thanks in advance

Answer 1

What do you mean by the "right" east and west points? A point at longitude -140 is to the east of a point at longitude 150 - no algorithm will correct that!

What server are you using? SQL Server 2008 has no problem with defining polygons that cross the dateline. E.g. POLYGON((150 20, -140 20, -140 60, 150 60, 150 20)) as shown below:

---

Beginning Spatial with SQL Server http://www.apress.com/book/view/1430218290

Answer 2

HI Tanosihmi

Thanks for the reply and sorry for the delay...

The way I solved my issue with antimeridian spanning is using two location rects like so

 LocationRect boundsE = new LocationRect(bounds.North, bounds.West, bounds.South, 180.0);
 LocationRect boundsW = new LocationRect(bounds.North, -180.0, bounds.South, bounds.East);

which I have seen in http://www.cadmaps.com/gisblog/?cat=10

thx

Roi