adds hotspot/coldspot function

src/pg/sql/16_getis.sql

@@ -0,0 +1,16 @@
+-- Getis-Ord's G
+-- Hotspot/Coldspot Analysis tool
+CREATE OR REPLACE FUNCTION
+  CDB_GetisOrdsG(
+      subquery TEXT,
+      column_name TEXT,
+      w_type TEXT,
+      num_ngbrs INT,
+      permutations INT,
+      geom_col TEXT,
+      id_col TEXT)
+RETURNS TABLE (z_val NUMERIC, p_val NUMERIC, rowid BIGINT)
+AS $$
+  from crankshaft.clustering import getis
+  return getis_ord(subquery, column_name, w_type, num_ngbrs, permutations, geom_col, id_col)
+$$ LANGUAGE plpythonu;