24/06/2026
Here's something most drone survey quotes won't tell you: photogrammetry fails silently on vegetated terrain. It returns the top of the canopy as if it were the ground, and most clients don't find out until the data is already with their engineer.
For years, the standard line on a drone survey started the same way: "Photogrammetry will be fine for your site." We said it too. Then we started mapping properties with heavy tree cover, standing crops, and long grasses, and the limitation kept showing up.
Photogrammetry sees what the camera sees. Under a canopy, the camera doesn't see the ground. The output looks clean, the contours look right, but the elevations carry systematic errors wherever vegetation gets in the way. Those errors flow straight into earthworks volumes, drainage design, and contour plans.
That is exactly why we developed our precision LIDAR service 📡 LIDAR pulses pe*****te gaps in foliage and return multiple hits per shot, so we can separate ground points from vegetation and deliver a true bare-earth surface, not a canopy model dressed up as one.
A couple of practical tips if you're commissioning aerial survey work: if your site has tree cover, crops, or grass over ankle height, ask specifically for LIDAR with bare-earth classification. And if the deliverable is a DTM for civil design, confirm how the ground points were actually derived, not just the stated accuracy.
Photogrammetry still does excellent work on open ground, stockpiles, quarries, and hard surfaces. It's a question of matching the sensor to the terrain. The accuracy number on the report only means something if the points being measured are actually the ground.
