Start a tool to compress Map files by removing information unnecessar…

…y to the bike network tool. #746

Just a modest start, switching from CHs to Dijkstra's for pathfinding. Not uploading the minified result yet.

importer/src/bin/minify_map.rs

@@ -0,0 +1,15 @@
+//! Removes nonessential parts of a Map, for the bike network tool.
+
+use abstutil::{CmdArgs, Timer};
+use map_model::Map;
+
+fn main() {
+    let mut args = CmdArgs::new();
+    let mut timer = Timer::new("minify map");
+    let mut map = Map::load_synchronously(args.required_free(), &mut timer);
+    args.done();
+
+    map.minify(&mut timer);
+    // This also changes the name, so this won't overwrite anything
+    map.save();
+}

map_model/src/map.rs

@@ -818,4 +818,18 @@ impl Map {
             && from.get_detailed_rank() < to.get_detailed_rank()
             && self.get_i(from.common_endpt(to)).is_stop_sign()
     }
+
+    /// Modifies the map in-place, removing parts not essential for the bike network tool. Also
+    /// modifies the name.
+    pub fn minify(&mut self, timer: &mut Timer) {
+        self.name.map = format!("minified_{}", self.name.map);
+
+        // Don't need CHs
+        self.pathfinder = Pathfinder::new(
+            self,
+            self.routing_params().clone(),
+            crate::pathfind::CreateEngine::Dijkstra,
+            timer,
+        );
+    }
 }