Definition
An orthophoto is an aerial image that has been geometrically corrected so that every part of it is at a consistent scale, like a map. Unlike an ordinary aerial photo, which has distortions from terrain and camera angle, an orthophoto lets you measure real distances directly on the image.
This correction makes orthophotos both visually rich and accurate, combining the detail of a photograph with the measurability of a map. They are a common output of drone and aerial mapping.
In simple terms, an orthophoto is a distortion-free aerial image you can measure like a map.
How It Works
Creating an orthophoto, a process called orthorectification, removes the distortions in raw aerial imagery caused by camera tilt and variations in terrain height. Software uses information about the camera and a model of the ground surface to reproject the image onto a flat, uniform scale.
The result is a seamless image, often stitched from many photos into an orthomosaic, where positions and distances are accurate everywhere. Ground control points help ensure the finished orthophoto is correctly georeferenced.
Applications
Orthophotos are used in surveying, planning, agriculture, and construction. They serve as accurate base maps, support measurement and area calculation, document site conditions, and provide a clear visual record. They are a staple deliverable of drone and aerial mapping.
Benefits
- Map-accurate measurement from aerial imagery.
- Rich visual detail combined with correct scale.
- Useful base maps for planning and design.
- Clear documentation of site conditions.
- Easy to combine with other spatial data.
Related Terms
- Aerial Mapping
- Photogrammetry
- Drone Mapping
- Ground Sampling Distance (GSD)
Frequently Asked Questions
What is an orthophoto used for?
It is used as an accurate base map for measurement, planning, and documentation in surveying, agriculture, and construction.
What is the difference between an orthophoto and a normal photo?
A normal aerial photo has distortions, while an orthophoto is corrected to a uniform scale so distances can be measured accurately.
How is an orthophoto made?
Through orthorectification, which removes distortions using camera data and a terrain model to reproject the image to a uniform scale.
What is an orthomosaic?
An orthomosaic is a single large orthophoto created by stitching together many corrected aerial images.
About Track3D
Track3D helps teams turn aerial imagery and orthophotos into accurate digital twins and insights. Learn more at Track3D.
