Understanding Orthomosaic Mapping

July 15, 2025 • By Jerome Sterling - Chief Pilot

What Is an Orthomosaic Map?

An orthomosaic is a single, seamless aerial image created by stitching together multiple overlapping photos. By correcting for camera tilt and terrain elevation, the result is a geometrically accurate, distortion-free map that supports precise measurements and GIS overlays.

Why Orthomosaics Matter

Orthomosaic maps enable accurate area calculations, volume estimates for stockpiles, and change detection over time—reducing field visits and improving decision-making for surveying, agriculture, and construction projects.

Key Flight Planning Factors

Maintaining 70–80% image overlap and flying at consistent altitudes (e.g., 200 ft AGL) ensures complete coverage and optimal ground sampling distance. Grid or lawnmower patterns capture uniform data, while perimeter passes fill edge details.

From Photos to Final Map

Photogrammetry software aligns overlapping images to build a 3D point cloud, applies bundle adjustment to refine sensor positions, and generates a digital elevation model (DEM) alongside the orthorectified image for GIS-ready output.

Example: 36‑Acre Survey at 200 ft

Conclusion