Auto clip vector tile geometries

Automatically clip all geometries in an MVT request. The clipping
rectangle is 6.25% larger than the tile. This will ensure that
geometry points that are outside the viewing tile area are not
included in the MVT binary, making for much smaller payloads,
particularly for lower zoom levels.

Author: tidwall

internal/server/mvt.go

@@ -7,7 +7,6 @@ import (
 	"github.com/tidwall/geojson"
 	"github.com/tidwall/geojson/geometry"
 	"github.com/tidwall/mvt"
-	"github.com/tidwall/tile38/internal/log"
 )
 
 type mvtObj struct {
@@ -135,6 +134,5 @@ func mvtFilterHTTPArgs(msg *Message, query string) (modified bool) {
 		msg.Args = append(msg.Args, "LIMIT", "100000000")
 	}
 	msg.Args = append(msg.Args, "MVT", parts[2], parts[3], parts[1])
-	log.HTTPf("%s", path)
 	return true
 }

internal/server/search.go

@@ -173,12 +173,11 @@ func parseRectArea(ltyp string, vs []string) (nvs []string,
 	}
 	nvs = vs
 	if ltyp == "mvt" {
-		// expand rectangle by 10%
-
-		rect.Min.Y -= (rect.Max.Y - rect.Min.Y) * 0.1
-		rect.Max.Y += (rect.Max.Y - rect.Min.Y) * 0.1
-		rect.Min.X -= (rect.Max.X - rect.Min.X) * 0.1
-		rect.Max.X += (rect.Max.X - rect.Min.X) * 0.1
+		// Expand rectangle by 0.0625%
+		rect.Min.Y -= (rect.Max.Y - rect.Min.Y) * 0.0625
+		rect.Max.Y += (rect.Max.Y - rect.Min.Y) * 0.0625
+		rect.Min.X -= (rect.Max.X - rect.Min.X) * 0.0625
+		rect.Max.X += (rect.Max.X - rect.Min.X) * 0.0625
 		if rect.Min.Y < bing.MinLatitude {
 			rect.Min.Y = bing.MinLatitude
 		}
@@ -386,6 +385,7 @@ func (s *Server) cmdSearchArgs(
 		}
 		if ltyp == "mvt" {
 			lfs.mvt = true
+			lfs.clip = true
 		}
 	case "get":
 		if lfs.clip {