Point Clouds: The Most Versatile Output in Drone Mapping

When most people think about drone mapping deliverables, they think about orthomosaics — the aerial map image. But the point cloud is arguably the most versatile and powerful output of a drone survey.

A point cloud is a collection of millions of 3D points, each with precise X, Y, Z coordinates and often additional attributes like color and intensity. It is the raw 3D representation of the surveyed surface — the foundation from which DEMs, meshes, contours, and measurements are derived.

Each point in a point cloud has:

• X, Y, Z coordinates — the 3D position of the point in a defined coordinate reference system
• RGB color (photogrammetry) — the color of the surface at that point, derived from the imagery
• Intensity (LiDAR) — the strength of the laser return, related to surface reflectivity
• Classification — a label indicating what the point represents (ground, vegetation, building, water, etc.)
• Return number (LiDAR) — for multi-return LiDAR, which return this point represents

A typical drone photogrammetry survey produces 50–500 million points. A LiDAR survey may produce 1–10 billion points for the same area.

Raw point clouds contain points representing everything in the scene — ground, vegetation, buildings, vehicles, and noise. Classification assigns each point to a category, enabling selective use of different point types.

Standard classification categories (per ASPRS LAS specification):

• Class 1 — Unclassified
• Class 2 — Ground
• Class 3 — Low vegetation
• Class 4 — Medium vegetation
• Class 5 — High vegetation
• Class 6 — Building
• Class 9 — Water
• Class 17 — Bridge deck

Classification is performed by automated algorithms, often followed by manual review and correction. Accurate classification is essential for producing reliable DTMs and for applications that require specific point types.

The most common use of point cloud classification is producing Digital Terrain Models (DTMs). By filtering the point cloud to include only ground-classified points, a bare-earth terrain surface can be generated that excludes vegetation and structures.

This is the foundation for drainage analysis, cut/fill calculations, and engineering design.

Point clouds enable precise volumetric analysis. By defining a base surface and measuring the volume of points above it, stockpile volumes, earthwork quantities, and other volumetric measurements can be calculated with high accuracy.

Building Information Modeling (BIM) workflows increasingly incorporate point cloud data from drone surveys. A point cloud of an existing building or site can be imported into Revit, Navisworks, or other BIM platforms to create as-built models or to verify that construction matches design.

This application is particularly valuable for renovation projects, where accurate as-built documentation is essential for design.

Point clouds can be rendered as 3D visualizations — interactive models that allow stakeholders to explore the site in three dimensions. This is valuable for client presentations, public engagement, and design review.

Comparing point clouds from two time periods reveals where the surface has changed. This is used for:

• Construction progress monitoring
• Erosion and deposition measurement
• Structural deformation monitoring
• Landslide and slope movement detection

Point clouds can be analyzed to extract specific features — building footprints, road centerlines, tree locations, and other objects. This extraction can be done manually or with AI-assisted algorithms.

Point clouds are large files that require specialized software to view and analyze. Common tools include:

• Autodesk ReCap — point cloud processing and visualization, integrates with AutoCAD and Revit
• CloudCompare — free, open-source point cloud processing and analysis
• ArcGIS Pro — GIS analysis with point cloud support
• Trimble RealWorks — professional point cloud processing
• Leica Cyclone — point cloud processing for survey and construction applications

For clients without point cloud software, web-based viewers (Potree, Cesium) allow interactive viewing in a browser without software installation.

The point cloud is the most information-rich output of a drone survey. For projects that require 3D analysis, BIM integration, or detailed volumetric measurement, requesting the point cloud in addition to the orthomosaic and DEM unlocks the full value of the drone survey.

Contact Blackridge Geospatial to discuss point cloud deliverables for your project.