geo/overlapCalc

Spatial intersection detection between lanes and other map elements, producing ApolloOverlap proto objects.

computeAllOverlaps

function computeAllOverlaps(params: {
  lanes: LaneFeature[]
  crosswalks: CrosswalkFeature[]
  signals: SignalFeature[]
  stopSigns: StopSignFeature[]
  junctions: JunctionFeature[]
  clearAreas: ClearAreaFeature[]
  speedBumps: SpeedBumpFeature[]
}): ComputedOverlap[]

Iterates all lane × element pairs and detects spatial intersections. Returns one ComputedOverlap per detected overlap.

Returns

Each ComputedOverlap contains:

interface ComputedOverlap {
  overlap: ApolloOverlap // ready-to-include proto object
  laneOverlapIds: Record<string, string[]> // laneId → overlap ID list
}

laneOverlapIds is a cumulative map built across all overlaps — buildBaseMap uses it to populate ApolloLane.overlap_id[].

---

Intersection methods by element type

Lane vs Polygon (crosswalk, clear area)

const polyLine = turf.polygonToLine(polygon) as Feature<LineString>
const intersections = turf.lineIntersect(centerLine, polyLine)

For each intersection point, nearestPointOnLine computes s on the centerline. The overlap s-range is [min(s), max(s)].

Lane vs Line (signal stop line, stop sign, speed bump)

const intersections = turf.lineIntersect(centerLine, stopLine)

Single intersection → s-point ± 0.5 m, clamped to [0, laneLength].

Lane vs Junction

const midPt = turf.point(centerLine.geometry.coordinates[Math.floor(n / 2)])
const inside = turf.booleanPointInPolygon(midPt, junction.polygon)

If inside: s-range = [0, laneLength] (entire lane is in junction).

---

ComputedOverlap

interface ComputedOverlap {
  overlap: ApolloOverlap
  laneOverlapIds: Record<string, string[]>
}

The overlap.object array contains exactly two entries:

1. The lane, with laneOverlapInfo: { startS, endS, isMerge: false }
2. The other element, with the appropriate *OverlapInfo: {} field set

Overlap ID format: overlap_N where N increments from 1 per computeAllOverlaps call (counter resets on each call).