Function to intersect another polygon using OpenLayers

Question

I wonder if someone here have a JavaScript function that when I draw a polygon I can see if I am drawing on another polygon?

like intersect... if polygon intersect say to me a alert...

using OpenLayers.

Answer 1

You can have a look at the intersection example of OpenLayers: http://dev.openlayers.org/examples/intersects.html

for(var i=0; i<features.length-1; ++i) 
{
 feat1 = features[i];
 for(var j=i+1; j<features.length; ++j) 
 {
 feat2 = features[j];
 intersects12 = feat1.geometry.intersects(feat2.geometry);
 if(intersects12) 
 {
 alert("Intersection");
 }
 }
}