The concept of Photogrammetry:
Photogrammetry is like creating a 2D and 3D map of something using many photos. Imagine taking lots of pictures of an object or a place from different angles, like how you would take selfies from different angles. Then, special software combines (stitches) all those photos to make a detailed 2D and 3D model, just like how your brain puts together all the different images to understand the world around you. This helps us measure and understand things in a way that normal photos or measurements can't do alone. The end result is all of the area scanned being shown on one high resolution image.
What do the results look like?
2D, also call Orthomosaic
This is an example of a commercial building. The drone took over 600 photos at 200 feet using a precise coordinate technology. Using software, the photos were stitched to create a high resolution overview in both 2D and 3D. Both overviews have the ability to zoom in for close inspection and also do centimeter accurate measurements, mark objects, and determines area dimension calculations.