Aerial surveying is the practice of collecting geospatial data from an elevated perspective, typically using aircraft, drones, or satellites. It uses specialized sensors, such as high-resolution cameras for photogrammetry or laser scanners for lidar (light detection and ranging), to capture detailed imagery and elevation data of project areas. The raw data is then processed into high-precision maps, 3D models, and digital elevation models using specialized software. This technique can be more efficient and safer than traditional ground-based surveying, especially for extensive or difficult-to-access terrain. Aerial surveying is used across many industries, including construction, engineering, and mining, to gather comprehensive and timely data for critical decision-making. 

Topographic mapping is the detailed, two-dimensional representation of the earth's three-dimensional surface, depicting both natural and human-made features. Unlike standard flat maps, topographic maps use contour lines, imaginary lines connecting points of equal elevation, to show the shape and relief of the land. The spacing of these lines reveals the slope of the terrain: closely spaced lines indicate steep ground, while widely spaced lines represent a gentle slope or flat area. These maps also include symbols for geographical features like roads, buildings, and utilities, making them essential tools for a wide range of fields, including civil engineering, construction, mining, and environmental monitoring.

A control survey establishes a precise network of horizontal and vertical reference points, known as control points, to serve as the foundation for other surveys such as aerial mapping. These permanent monuments, which may be tied to a national spatial reference system like the National Spatial Reference System (NSRS), have highly accurate known coordinates and elevations. All subsequent surveying and mapping work for engineering, construction, and land development projects is based on these control points to ensure consistency, minimize error, and maintain accuracy throughout the project lifecycle.

Using photogrammetry or lidar technology, drones capture precise data to calculate volume measurements for stockpiles, earthworks, and other materials in industries like construction, mining, and engineering. In a typical survey, a drone equipped with a high-resolution camera or laser sensor follows a programmed flight path over a designated area. The drone gathers either hundreds of overlapping photographs (photogrammetry) or millions of laser-measured data points (lidar). This data is then processed by specialized software to generate highly accurate, detailed 3D models and digital surface maps. By establishing a base surface and analyzing the reconstructed 3D model, the software can quickly calculate volume, compare changes over time, and provide accurate reports that are faster, safer, and more cost-effective than traditional ground-based surveying.

An as-built survey provides a detailed, accurate blueprint of a construction project after it has been completed. It documents the precise location, dimensions, and other specifications of all constructed features, including buildings, utilities, grading, and infrastructure, reflecting any deviations from the original design plans. These surveys are crucial for verifying that work was performed according to the project plans and local regulations, and are often required for obtaining a certificate of occupancy. The resulting as-built drawings serve as a permanent record for future maintenance, renovations, or expansion projects.