Changes between Version 4 and Version 5 of UsersWikiExamplesNetworkTopology

Timestamp:

06/14/09 20:41:37 (16 years ago)

Author:

kneufeld

Comment:

--

UsersWikiExamplesNetworkTopology

@@ -114 +114 @@
 
 
+{{{
+-- Sample data from the new roads table
+SELECT road_id, from_node, to_node FROM roads WHERE road_id = 834;
+ road_id | from_node | to_node
+---------+-----------+---------
+     834 |      1751 |    1759
+(1 row)
+}}}
+
+
 '''Notes''': Alternatively, we could have first created a distinct set of nodes, assigned a unique id to the nodes, and spatially transferred a node_id attribute to every road by intersecting the roads and nodes.  However, such spatial operations are very expensive to perform.  Also, in this case, it's not needed since we already have a relationship between a line and a node (the node is just the start or end point of the line it originated from).