Fix very silly problem in GeoJSON importer

CHANGES.md

@@ -9,6 +9,8 @@ changes.
 
 - Removed `fetchWithProgress`, which is a general-purpose utility method that
   should come from another library
+- Improved the tool that makes graphs from GeoJSON files by splitting
+  LineStrings that touch at interior points
 
 ## 0.4.0
 

geojson-to-route-snapper/src/lib.rs

@@ -31,10 +31,11 @@ pub fn convert_geojson(input_string: String) -> Result<RouteSnapperMap> {
     // Split each LineString into edges
     let mut node_id_lookup: HashMap<(isize, isize), NodeID> = HashMap::new();
     for edge in input {
-        let mut point1 = *edge.geometry.coords().next().unwrap();
+        let mut point1 = edge.geometry.0[0];
         let mut pts = Vec::new();
 
         let num_points = edge.geometry.coords_count();
+
         for (idx, pt) in edge.geometry.into_inner().into_iter().enumerate() {
             pts.push(pt);
             // Edges start/end at intersections between two LineStrings. The endpoints of the
@@ -49,12 +50,12 @@ pub fn convert_geojson(input_string: String) -> Result<RouteSnapperMap> {
                 let node1_id = *node_id_lookup
                     .entry(hashify_point(point1))
                     .or_insert_with(|| {
-                        map.nodes.push(geometry.0[0]);
+                        map.nodes.push(point1);
                         next_id
                     });
                 let next_id = NodeID(node_id_lookup.len() as u32);
                 let node2_id = *node_id_lookup.entry(hashify_point(pt)).or_insert_with(|| {
-                    map.nodes.push(*geometry.0.last().unwrap());
+                    map.nodes.push(pt);
                     next_id
                 });
                 map.edges.push(Edge {
@@ -69,11 +70,11 @@ pub fn convert_geojson(input_string: String) -> Result<RouteSnapperMap> {
                 });
                 map.override_forward_costs.push(edge.forward_cost);
                 map.override_backward_costs.push(edge.backward_cost);
-            }
 
-            // Start the next edge
-            point1 = pt;
-            pts.push(pt);
+                // Start the next edge
+                point1 = pt;
+                pts.push(pt);
+            }
         }
     }
 

user_guide.md

@@ -35,13 +35,18 @@ cd geojson-to-route-snapper
 cargo run --release -- --input path_to_network.geojson
 ```
 
-The LineStrings must represent edges, meaning the ends need to have the same
-coordinate as other LineStrings. Each LineString has some properties:
+For routing to work, the LineStrings must share points with other LineStrings.
+If you have one long LineString touching many others and the points are the
+same, these will be split into edges automatically. LineStrings that cross but
+don't share points (within 7 decimal places) won't connect.
+
+Each LineString has some properties:
 
 - an optional numeric `forward_cost` and `backward_cost`.
 
-  Costs **must** be specified for some of the edges in the file. 
-  If a cost is missing, the edge won't be routable in that direction.
+  Costs **must** be specified for some of the edges in the file. If a cost is
+  missing, the edge won't be routable in that direction. Use `null` to indicate
+  the edge isn't routable at all in that direction.
 
 - an optional string `name`.