# HG changeset patch
# User Tom Gottfried <tom@intevation.de>
# Date 1538668019 -7200
# Node ID 862cc5ba4d1dfda74cea0cc1262fbf47d80c8d1f
# Parent  271561dce2e6d6efc8c084c191c84828d5b14216
Merge contour lines

Lines have been stored as multilinestrings comprised of adjacent
2-vertex linestrings. Merging these to longer linestrings will
allow further processing such as simplification.

diff -r 271561dce2e6 -r 862cc5ba4d1d cmd/octree2contour/store.go
--- a/cmd/octree2contour/store.go	Thu Oct 04 16:32:47 2018 +0200
+++ b/cmd/octree2contour/store.go	Thu Oct 04 17:46:59 2018 +0200
@@ -26,14 +26,14 @@
   sr.id,
   $1,
   ST_Transform(
-    ST_CollectionExtract(
-      ST_Force2D(
+    ST_Multi(
+      ST_CollectionExtract(
         ST_Intersection(
           ST_Transform(sr.area::geometry, $3::integer),
-          ST_GeomFromWKB($2, $3::integer)
-        )
-      ),
-      2
+          ST_LineMerge(ST_Force2D(ST_GeomFromWKB($2, $3::integer)))
+        ),
+        2
+      )
     ),
     4326
   )