do not add prepared geometries to index

geom/geos/index.go

@@ -19,11 +19,9 @@ import (
 )
 
 // IndexGeom is a struct for indexed geometries used by Index
-// and returned by IndexQuery. Access to Prepared requires acquiring .Lock()
+// and returned by IndexQuery.
 type IndexGeom struct {
-	*sync.Mutex // Mutex for Prepared
-	Geom        *Geom
-	Prepared    *PreparedGeom
+	Geom *Geom
 }
 type Index struct {
 	v     *C.GEOSSTRtree
@@ -45,8 +43,7 @@ func (this *Geos) IndexAdd(index *Index, geom *Geom) {
 	defer index.mu.Unlock()
 	id := len(index.geoms)
 	C.IndexAdd(this.v, index.v, geom.v, C.size_t(id))
-	prep := this.Prepare(geom)
-	index.geoms = append(index.geoms, IndexGeom{&sync.Mutex{}, geom, prep})
+	index.geoms = append(index.geoms, IndexGeom{geom})
 }
 
 // IndexQuery queries the index for intersections with geom.

geom/limit/limit.go

@@ -287,19 +287,13 @@ func (l *Limiter) Clip(geom *geos.Geom) ([]*geos.Geom, error) {
 	var intersections []*geos.Geom
 	// intersect with each part...
 	for _, hit := range hits {
-		hit.Lock()
-		if g.PreparedIntersects(hit.Prepared, geom) {
-			hit.Unlock()
-			newPart := g.Intersection(hit.Geom, geom)
-			if newPart == nil {
-				continue
-			}
-			newParts := filterGeometryByType(g, newPart, geomType)
-			for _, p := range newParts {
-				intersections = append(intersections, p)
-			}
-		} else {
-			hit.Unlock()
+		newPart := g.Intersection(hit.Geom, geom)
+		if newPart == nil {
+			continue
+		}
+		newParts := filterGeometryByType(g, newPart, geomType)
+		for _, p := range newParts {
+			intersections = append(intersections, p)
 		}
 	}
 	// and merge parts back to our clipped intersection