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Use a queue to merge short roads, instead of a potentially quadratic scan. #114

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This commit is contained in:
Dustin Carlino 2021-01-15 20:52:11 -08:00
parent 8ec1e5a807
commit 3cdbe74948
1 changed files with 29 additions and 28 deletions
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57
map_model/src/make/merge_intersections.rs
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@ -1,9 +1,9 @@
use std::collections::BTreeSet;
use std::collections::{BTreeSet, VecDeque};
use geom::Distance;
use crate::osm::NodeID;
use crate::raw::RawMap;
use crate::raw::{OriginalRoad, RawMap};
// Manually adjust this to try locally. Need to work through issues with merging before enabling
// generally.
@ -14,35 +14,36 @@ const SHORT_ROAD_THRESHOLD: Distance = Distance::const_meters(0.0);
pub fn merge_short_roads(map: &mut RawMap) -> BTreeSet<NodeID> {
let mut merged = BTreeSet::new();
// An expensive fixed-point approach. When we merge one road, the IDs of some other roads might
// change, so it's simplest just to start over.
// TODO But since merge_short_road tells us what road IDs were deleted and created, it wouldn't
// be hard to make a single pass.
loop {
let mut changes = false;
for (id, road) in map.roads.clone() {
// See https://wiki.openstreetmap.org/wiki/Proposed_features/junction%3Dintersection
if road.osm_tags.is("junction", "intersection")
|| map
.trimmed_road_geometry(id)
.map(|pl| pl.length() < SHORT_ROAD_THRESHOLD)
.unwrap_or(false)
{
match map.merge_short_road(id) {
Ok((i, _, _, _)) => {
merged.insert(i);
changes = true;
break;
}
Err(err) => {
warn!("Not merging short road / junction=intersection: {}", err);
}
let mut queue: VecDeque<OriginalRoad> = VecDeque::new();
for r in map.roads.keys() {
queue.push_back(*r);
}
while !queue.is_empty() {
let id = queue.pop_front().unwrap();
// The road might've been deleted
if !map.roads.contains_key(&id) {
continue;
}
// See https://wiki.openstreetmap.org/wiki/Proposed_features/junction%3Dintersection
if map.roads[&id].osm_tags.is("junction", "intersection")
|| map
.trimmed_road_geometry(id)
.map(|pl| pl.length() < SHORT_ROAD_THRESHOLD)
.unwrap_or(false)
{
match map.merge_short_road(id) {
Ok((i, _, _, new_roads)) => {
merged.insert(i);
queue.extend(new_roads);
}
Err(err) => {
warn!("Not merging short road / junction=intersection: {}", err);
}
}
}
if !changes {
break;
}
}
merged