When importing external scenario data, snap points outside the map boundary to the nearest border.

Now the desire lines for cyipt/actdev#32 import without errors.

book/src/trafficsim/travel_demand.md

@@ -113,12 +113,13 @@ Run the tool:
 cargo run --bin import_traffic -- --map=data/system/seattle/maps/montlake.bin --input=/path/to/input.json
 ```
 
-The tool matches input positions to the nearest building or border intersection,
-within 100 meters. The `departure` time is seconds since midnight. The tool will
-fail if any point doesn't match to a building, or if any of the specified trips
-can't be created (due to graph connectivity problems, for example). If your
-requirements are different or you have any trouble using this format/tool,
-please file a Github issue -- just consider this tool and format a prototype.
+The tool matches input positions to the nearest building, within 100 meters. If
+the point lies outside the map boundary, it's snapped to the nearest map border.
+The `departure` time is seconds since midnight. The tool will fail if any point
+doesn't match to a building, or if any of the specified trips can't be created
+(due to graph connectivity problems, for example). If your requirements are
+different or you have any trouble using this format/tool, please file a Github
+issue -- just consider this tool and format a prototype.
 
 ## Modifying demand
 

data/MANIFEST.json

@@ -41,9 +41,9 @@
       "compressed_size_bytes": 2845017
     },
     "data/input/cambridge/desire_lines_disag.geojson": {
-      "checksum": "37020c1232b357b8f5753157eaf6b95f",
-      "uncompressed_size_bytes": 66601,
-      "compressed_size_bytes": 6385
+      "checksum": "1cb0f5fc91626099dca6582c97f49c43",
+      "uncompressed_size_bytes": 80600,
+      "compressed_size_bytes": 11174
     },
     "data/input/cambridge/osm/cambridgeshire-latest.osm.pbf": {
       "checksum": "e7ac328f5b13c1a90da861abc84ae08d",
@@ -645,6 +645,16 @@
       "uncompressed_size_bytes": 28191229,
       "compressed_size_bytes": 9988667
     },
+    "data/system/cambridge/scenarios/trumpington/baseline.bin": {
+      "checksum": "661ce8362a2854023d24822b9f2bb8fe",
+      "uncompressed_size_bytes": 71752,
+      "compressed_size_bytes": 18953
+    },
+    "data/system/cambridge/scenarios/trumpington/go_dutch.bin": {
+      "checksum": "b87b56638974c3ca6b88b498ac655a35",
+      "uncompressed_size_bytes": 71752,
+      "compressed_size_bytes": 18791
+    },
     "data/system/krakow/maps/center.bin": {
       "checksum": "6b39b2b5a2066603cbe5e4dc087e7071",
       "uncompressed_size_bytes": 36111431,

data/regen.sh

@@ -7,7 +7,7 @@ rm -fv data/system/seattle/maps/huge_seattle.bin data/input/raw_maps/huge_seattl
 ./import.sh --raw --map --scenario
 ./import.sh --raw --map --city=bellevue
 ./import.sh --raw --map --city=berlin
-./import.sh --raw --map --city=cambridge	# TODO Enable --scenario
+./import.sh --raw --map --city=cambridge --scenario
 ./import.sh --raw --map --city=krakow
 ./import.sh --raw --map --city=leeds
 ./import.sh --raw --map --city=london

sim/src/make/external.rs

@@ -29,23 +29,39 @@ pub enum ExternalTripEndpoint {
 }
 
 impl ExternalPerson {
+    /// Import external scenario data. The main difference between `ExternalPerson` and
+    /// `PersonSpec` is a way to specify endpoints by a `LonLat`. This is snapped to the nearest
+    /// building. If the point is outside of the map boundary, it's snapped to the nearest border
+    /// (by Euclidean distance -- the network outside the given map isn't known). Failure happens
+    /// if a point is within the map, but not close enough to any buildings.
     pub fn import(map: &Map, input: Vec<ExternalPerson>) -> Result<Vec<PersonSpec>> {
         let mut closest: FindClosest<TripEndpoint> = FindClosest::new(map.get_bounds());
         for b in map.all_buildings() {
             closest.add(TripEndpoint::Bldg(b.id), b.polygon.points());
         }
+        let mut borders = Vec::new();
         for i in map.all_intersections() {
-            closest.add(TripEndpoint::Border(i.id), i.polygon.points());
+            if i.is_border() {
+                borders.push((TripEndpoint::Border(i.id), i.polygon.center()));
+            }
         }
+
         let lookup_pt = |endpt| match endpt {
             ExternalTripEndpoint::TripEndpoint(endpt) => Ok(endpt),
             ExternalTripEndpoint::Position(gps) => {
-                match closest.closest_pt(gps.to_pt(map.get_gps_bounds()), Distance::meters(100.0)) {
-                    Some((x, _)) => Ok(x),
-                    None => Err(anyhow!(
-                        "No building or border intersection within 100m of {}",
-                        gps
-                    )),
+                let pt = gps.to_pt(map.get_gps_bounds());
+                if map.get_boundary_polygon().contains_pt(pt) {
+                    match closest.closest_pt(pt, Distance::meters(100.0)) {
+                        Some((x, _)) => Ok(x),
+                        None => Err(anyhow!("No building within 100m of {}", gps)),
+                    }
+                } else {
+                    Ok(borders
+                        .iter()
+                        .min_by_key(|(_, border)| border.fast_dist(pt))
+                        .unwrap()
+                        .0
+                        .clone())
                 }
             }
         };