HD Map Engineer

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§ 1 · System Prompt

[Code block moved to code-block-1.md]

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§ 10 · Common Pitfalls & Anti-Patterns

Anti-Pattern 1: Raster Map for AV Consumption

Name: The BMP Lane Boundary Engineer

❌ BAD:

# Storing lane boundaries as a PNG raster — no topology, no querying
lane_map = cv2.imread('lane_map_grid.png')
lane_pixels = np.where(lane_map[:,:,2] > 200)  # blue = lane boundary pixels

✅ GOOD:

# Lanelet2 vectorized format with routing graph
import lanelet2
map_ = lanelet2.io.load('/path/to/map.osm',
    lanelet2.projection.UtmProjector(lanelet2.io.Origin(51.0, 13.0)))
routing_graph = lanelet2.routing.RoutingGraph(
    map_, lanelet2.traffic_rules.create(
        lanelet2.traffic_rules.Locations.Germany,
        lanelet2.traffic_rules.Participants.Vehicle))
# Vectorized query: lanelets within 50m
ego_pos = lanelet2.core.BasicPoint2d(x, y)
nearby = lanelet2.geometry.findNearest(map_.laneletLayer, ego_pos, 10)

Why it matters: Raster maps cannot express topology (lane adjacency, successor relations), cannot support efficient spatial queries, and cannot store regulatory elements (traffic lights, stop lines) in a queryable format.

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Anti-Pattern 2: Assuming Map is Always Fresh

Name: The Eternal Map Truster

❌ BAD:

# No freshness check — uses map unconditionally
lane_boundaries = hd_map.get_lane_boundaries(ego_position)
planner.set_lane_constraints(lane_boundaries)  # could be a closed construction zone

✅ GOOD:

from datetime import datetime

map_metadata = hd_map.get_segment_metadata(ego_position)
age_hours = (datetime.now() - map_metadata.last_verified).total_seconds()

if age_hours > 48:
    # Stale map: fall back to camera lane detection
    lane_boundaries = camera_lane_detector.detect_lanes(camera_image)
    planning_mode = 'PERCEPTION_ONLY'
    log_warning(f"Map segment age {age_hours:.1f}h exceeds SLA. Using perception fallback.")
else:
    lane_boundaries = hd_map.get_lane_boundaries(ego_position)
    planning_mode = 'HD_MAP_GUIDED'

Why it matters: Construction zones appear and disappear on timescales of hours. A map verified 2 weeks ago can be lethal at a specific location. AV deployments without freshness monitoring are a safety liability.

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Anti-Pattern 3: Ignoring Localization-Map Accuracy Budget

Name: The Independent Accuracy Fallacy

❌ BAD:

"Our HD map is 5cm accurate, so our lane-level positioning is 5cm accurate."

✅ GOOD:

Total lateral positioning error = sqrt(map_accuracy^2 + localization_accuracy^2)
Example: map=5cm, localization=8cm -> total = sqrt(0.05^2 + 0.08^2) = 9.4cm  (OK)
Degraded: map=5cm, localization=15cm -> total = sqrt(0.05^2 + 0.15^2) = 15.8cm (FAIL)

Design requirement: total < 10cm
=> requires BOTH map < 5cm AND localization < 8.7cm simultaneously
=> monitor both components independently with per-frame health checks

Why it matters: Teams routinely report map accuracy without localization accuracy. The system accuracy is dominated by the weaker component, not the average.

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Anti-Pattern 4: No Map QA Automation

Name: The Trust-the-Annotator Approach

❌ BAD: Manual annotation without automated topology and geometry validation. Annotators make errors — dangling lanelets, missing stop lines, incorrect lane connectivity.

✅ GOOD:

def run_map_qa(map_) -> list:
    """Automated QA checks. Returns list of error strings."""
    errors = []
    routing_graph = lanelet2.routing.RoutingGraph(map_, ...)
    for ll in map_.laneletLayer:
        # Dangling lanelet check
        if not routing_graph.following(ll) and not is_terminal_lanelet(ll):
            errors.append(f"DANGLING_LANELET: id={ll.id}")
        # Width sanity check
        width = lanelet2.geometry.width(ll)
        if not (2.0 <= width <= 6.0):
            errors.append(f"INVALID_WIDTH: id={ll.id}, width={width:.2f}m")
        # Stop line required at signalized intersections
        if is_signalized_entry(ll) and not has_stop_line(ll):
            errors.append(f"MISSING_STOP_LINE: signalized entry id={ll.id}")
    return errors  # empty list = map passes QA

Why it matters: A dangling lanelet at an intersection exit can cause the routing planner to plan a route that drives off-road. Automated QA catches these errors in minutes rather than in field testing.

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Anti-Pattern 5: Coordinate System Ambiguity

Name: The WGS84/UTM Confusion Engineer

❌ BAD:

# Mixing coordinate systems — no units, no datum specified
map_point  = np.array([13.745, 51.024])   # lat/lon degrees? UTM meters?
ego_point  = np.array([13.746, 51.025])
distance   = np.linalg.norm(map_point - ego_point)  # meaningless: 0.0014... what unit?

✅ GOOD:

from pyproj import Proj

# Explicit coordinate system: WGS84 lat/lon -> UTM zone 33N for metric operations
utm33 = Proj(proj='utm', zone=33, datum='WGS84')

map_x,  map_y  = utm33(13.745, 51.024)   # outputs meters in UTM
ego_x,  ego_y  = utm33(13.746, 51.025)

distance_m = np.sqrt((ego_x - map_x)**2 + (ego_y - map_y)**2)
print(f"Distance: {distance_m:.2f} m")   # meaningful metric distance

Why it matters: A 1-degree confusion between lat/lon and UTM easting/northing produces a 111 km systematic error. Always annotate coordinate systems explicitly in every data structure and function signature.

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§ 11 · Integration with Other Skills

Skill	Integration Workflow	Combined Outcome
planning-decision-engineer	Feed Lanelet2 lane graph as structured routing constraints into behavior planner; regulatory elements (speed limits, stop lines) as hard planning constraints	Map-aware planning with lane routing, traffic sign compliance, and intersection management; reduces unknown unsafe scenario space
perception-algorithm-engineer	Online lane detection outputs compared against HD map priors; disagreement > 30cm triggers map staleness flag; fleet data aggregated for change detection	Self-diagnosing map freshness monitor using fleet perception data; automatically identifies construction zones and map update needs
autonomous-driving-engineer	HD map localization accuracy feeds into ASIL allocation for lane-keeping; < 10cm lateral supports ASIL-C; > 30cm requires ASIL decomposition with camera corroboration	Complete map-in-the-loop safety case with ASIL allocation of localization pipeline; documented degradation states

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§ 12 · Scope & Limitations

Use when:

• Designing, building, or maintaining HD map pipelines for autonomous vehicles in structured road environments.
• Selecting between OpenDRIVE and Lanelet2 formats for a specific AV stack.
• Implementing LiDAR-to-map localization (NDT/ICP) for centimeter-level positioning.
• Evaluating online map prediction models (MapTR, HDMapNet) as alternatives to offline HD maps.
• Designing map update and freshness monitoring systems for production fleets.

Do NOT use when:

• Designing the ego trajectory planner that consumes the map — use planning-decision-engineer skill.
• Implementing the LiDAR perception detection stack — use perception-algorithm-engineer skill.
• V2X-based dynamic map updates (traffic signal timing, hazard broadcasting) — use v2x-system-engineer skill.

Alternatives:

• For mapless driving in unstructured environments: online prediction (MapTR) + perception-algorithm-engineer.
• For full AV stack integration: autonomous-driving-engineer skill.

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§ 14 · Quality Verification

→ See references/standards.md §7.10 for full checklist

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References

Detailed content:

• ## § 2 · What This Skill Does
• ## § 3 · Risk Disclaimer
• ## § 4 · Core Philosophy
• ## § 6 · Professional Toolkit
• ## § 7 · Standards & Reference
• ## § 8 · Workflow
• ## § 9 · Scenario Examples
• ## § 20 · Case Studies

Examples

Example 1: Standard Scenario

Input: Design and implement a hd map engineer solution for a production system Output: Requirements Analysis → Architecture Design → Implementation → Testing → Deployment → Monitoring

Key considerations for hd-map-engineer:

• Scalability requirements
• Performance benchmarks
• Error handling and recovery
• Security considerations

Example 2: Edge Case

Input: Optimize existing hd map engineer implementation to improve performance by 40% Output: Current State Analysis:

• Profiling results identifying bottlenecks
• Baseline metrics documented

Optimization Plan:

1. Algorithm improvement
2. Caching strategy
3. Parallelization

Expected improvement: 40-60% performance gain

Workflow

Phase 1: Requirements

• Gather functional and non-functional requirements
• Clarify acceptance criteria
• Document technical constraints

Done: Requirements doc approved, team alignment achieved Fail: Ambiguous requirements, scope creep, missing constraints

Phase 2: Design

• Create system architecture and design docs
• Review with stakeholders
• Finalize technical approach

Done: Design approved, technical decisions documented Fail: Design flaws, stakeholder objections, technical blockers

Phase 3: Implementation

• Write code following standards
• Perform code review
• Write unit tests

Done: Code complete, reviewed, tests passing Fail: Code review failures, test failures, standard violations

Phase 4: Testing & Deploy

• Execute integration and system testing
• Deploy to staging environment
• Deploy to production with monitoring

Done: All tests passing, successful deployment, monitoring active Fail: Test failures, deployment issues, production incidents