Point Cloud Basics
A beginner-friendly introduction to point clouds — what they are, how they're captured, and how to work with them in SkyGIS.
What Is a Point Cloud?
A point cloud is a collection of data points in 3D space. Each point has X, Y, and Z coordinates, and may include additional attributes like color (RGB), intensity, classification, or timestamp. Together, millions or billions of these points create a detailed 3D representation of a physical environment.
How Are Point Clouds Captured?
Terrestrial Laser Scanning (TLS)
A tripod-mounted scanner rotates and emits laser pulses that bounce off surrounding surfaces. The scanner measures the time-of-flight to calculate distances, building a dense 3D model of the environment. Typical resolution: 1–5mm point spacing.
Mobile Laser Scanning (MLS)
Scanners mounted on vehicles, backpacks, or handheld devices capture data while moving. Lower point density than TLS but covers large areas quickly. Ideal for corridors — roads, railways, tunnels.
Aerial Laser Scanning (ALS)
LiDAR sensors mounted on aircraft or drones capture terrain and surface data from above. Lower density than ground-based methods but covers vast areas efficiently. Essential for topographic mapping and forestry.
Photogrammetry
Point clouds generated from overlapping photographs using structure-from-motion algorithms. Lower accuracy than LiDAR but accessible with consumer cameras or drones.
Key Attributes
- Position (XYZ) — The fundamental spatial coordinate of each point
- Intensity — Strength of the returned laser signal, useful for material identification
- Color (RGB) — True color from photographs or scanner cameras
- Classification — Labels like ground, vegetation, building, noise (per ASPRS standard)
- Return number — For multi-return LiDAR: first return (canopy), last return (ground)
- Timestamp — When the point was captured, enabling trajectory reconstruction
Working with Point Clouds in SkyGIS
Upload & Processing
Upload your point cloud files (E57, LAS, TXT) and SkyGIS automatically indexes them for streaming. No desktop pre-processing required. Files of any size are supported — from small room scans to city-scale aerial surveys.
Visualization
Navigate your point cloud in real time. SkyGIS uses progressive level-of-detail rendering to maintain smooth performance regardless of dataset size. Color points by RGB, intensity, classification, or elevation.
Measurement
Measure distances, areas, and angles directly on the point cloud. All measurements snap to the nearest point for accuracy.
Common File Sizes
SkyGIS handles all of these sizes with the same streaming approach — no local downloads required.