What it is
Light detection and ranging (LiDAR) instruments estimate distance by measuring returned laser pulses. Mobile, airborne, and stationary systems produce point clouds that can describe streets, structures, and nearby objects. The measurements require calibration, coordinate alignment, and interpretation; a point cloud is not a complete or automatically current representation of a place.
How the system fits together
Ranging instrument
Scanner, laser, timing electronics, and calibration determine measurement range and accuracy.
Position and orientation
GNSS, inertial measurement, and control points align observations to a coordinate reference.
Processing
Point clouds are filtered, classified, and compared with reference data to identify features or change.
Use and stewardship
Survey provenance, permissions, privacy review, and update cadence determine whether derived maps are fit for use.
- 01
Ranging instrument
- 02
Position and orientation
- 03
Processing
- 04
Use and stewardship
Where cities use it
- Street and sidewalk inventory
- Tree canopy and urban form mapping
- Bridge and asset inspection
- Vehicle and robotics perception
Data generated
- Three-dimensional point clouds
- Trajectory and position metadata
- Classified surfaces and objects
- Survey control and quality reports
Analytics and AI applications
- Computer vision and object classification
- Change detection
- Geospatial measurement
- Digital twin model updates
Example in practice
A public works team compares a new mobile LiDAR survey with its street asset inventory to find missing curb ramps. Staff inspect candidate locations in the field before changing the authoritative record.
Design considerations
Choose sensor placement and refresh rates from an operational need. Keep device identity, calibration, network health, and location visible to the team using the data.
Limits and risks
- Dense mapping can be costly to collect, process, store, and refresh.
- Occlusion and reflective or absorptive surfaces affect measurement quality.
- Mapped detail can expose sensitive spaces and may be unsuitable for public release at full resolution.