Drawing lanes
Lanes are the core authoring unit of an Apollo HD Map. This page walks through the full pipeline: pick tool → drop anchors → commit → boundary offset → topology stitch → junction membership.
Pipeline
createLaneFromCurve(curve, halfWidth) produces:
centralCurve.segments[].lineSegment.points— lon/lat WGS84leftBoundary/rightBoundaryoffset perpendicular bylaneHalfWidth(default 1.5 m)lengthvia haversine (src/lib/geo.ts:35-42)- defaults:
type=CITY_DRIVING,turn=NO_TURN,direction=FORWARD
Steps
1. Pick lane → tool
ToolStrip's lane element exposes drawBezier (default) and drawArc only (src/core/elements.ts:50-58).
2. Drop anchors
- drawBezier: click anchor, drag to set tangent (handleOut), release; repeat. Double-click to commit. Anchors with no drag (< 1e-6 deg displacement) become corners (
handleIn/Out = null). - drawArc: click 1 = start, click 2 = arc midpoint, click 3 = end (commits).
3. Commit & boundary offset
4. Boundary types
The seven BoundaryLineType values (src/types/apollo.ts:74-81):
| Value | Visual | Semantics |
|---|---|---|
UNKNOWN | grey | unspecified |
DOTTED_YELLOW | yellow dashed | bidirectional, lane change allowed |
DOTTED_WHITE | white dashed | same-direction, lane change allowed |
SOLID_YELLOW | yellow solid | centre line, no crossing |
SOLID_WHITE | white solid | no crossing (ramp boundary, etc.) |
DOUBLE_YELLOW | double yellow | strict no-crossing |
CURB | curb | physical separation |
LaneBoundary.boundaryType is an array of {s, types[]} entries in ascending s. A single boundary can switch from DOTTED_WHITE to SOLID_WHITE along its length.
5. Neighbour twin
Four neighbour lists on LaneEntity:
leftNeighborForwardIds— same direction, on the leftrightNeighborForwardIds— same direction, on the rightleftNeighborReverseIds— opposite direction, on the leftrightNeighborReverseIds— opposite direction, on the right
reconcileLaneTopology derives these from central-curve heading + geometric adjacency. See Topology.
6. Junction insertion
Lanes whose endpoints fall inside a junction polygon receive junctionId. stitchLaneJunctions snaps continuous end-start pairs to a shared miter point.
Start-start / End-end exclusion
isContinuousJunction rejects start-start (forks) and end-end (merges) pairs (src/core/geometry/laneJunctions.ts:88-90). Pulling those boundaries to a shared miter point corrupts the visible split/merge geometry; topology and overlap entities handle them instead.
Options table
| Option | Default | Notes |
|---|---|---|
| Tool | drawBezier | MAP_ELEMENTS[lane].defaultTool |
laneHalfWidth | 1.5 m | settingsStore.laneHalfWidth |
LaneType | CITY_DRIVING | 7 values: NONE / CITY_DRIVING / BIKING / SIDEWALK / PARKING / SHOULDER / SHARED |
LaneTurn | NO_TURN | NO_TURN / LEFT_TURN / RIGHT_TURN / U_TURN |
LaneDirection | FORWARD | FORWARD / BACKWARD / BIDIRECTION |
| Boundary default | SOLID_WHITE | per-s entries |
| Initial samples | [{ s: 0, width: 1.5 }] | extended via inspector |
Shortcut cheatsheet
| Action | Key / Mouse | Notes |
|---|---|---|
| Pick lane | ToolStrip lane icon | activates MAP_ELEMENTS[lane] |
| Bezier / Arc | B / A | tool actions |
| Drop anchor | click | MOUSE_DOWN |
| Drag tangent | hold + move | MOUSE_MOVE [isDraggingHandle] |
| Commit | dbl-click / 3rd click | DOUBLE_CLICK / [twoPointsLaid] |
| Cancel | Esc | CANCEL |
| Select & edit | click lane → drag handle | selected → editingPoint |
| Connect lanes | C | predecessor/successor stitching mode |
Troubleshooting
Boundary looks jagged
Phase E incremental decoration may have skipped a frame. Check useColdLayer INCREMENTAL path; refresh once.
Lane endpoints don't snap at junction
Only continuous (end-start) pairs are stitched. Use connectLanes or move endpoints manually.
Half-width change doesn't propagate
settingsStore.laneHalfWidth only affects future lanes. Edit existing leftSamples/rightSamples in the inspector or redraw.
Neighbor side wrong
reconcileLaneTopology uses central-curve heading. If LaneEntity.direction is wrong, neighbours classify wrong. Fix direction first.
lane.length differs from GIS tools
Editor uses haversine (sphere). Lane-scale error < 0.5 %. External GIS may use ellipsoidal geodesic — expect tens-of-cm divergence.
Source links
src/core/elements.ts:50-58src/types/apollo.ts:74-164src/lib/entityOps.tssrc/core/geometry/laneOffset.tssrc/core/geometry/laneJunctions.tssrc/core/elements/derive/src/lib/geo.ts:22-42
See also
Contributors
kent