Support more region utils, such as convex hull

script/sql/create/32.region.sql

@@ -5,3 +5,27 @@ create table region
 );
 
 create index region_gist on region using gist(boundary);
+
+
+create table temp_region
+(
+  id text primary key
+, boundary geometry not null unique
+);
+
+create index temp_region_gist on temp_region using gist(boundary);
+
+
+create table temp_node
+(
+  node varchar(32) primary key references _node(id)
+);
+
+
+create table temp_vd_topology
+(
+  id serial
+, source integer
+, target integer
+, cost numeric
+);