CASE FILE 004 · LIDAR & MAPPING · WESTERN WISCONSIN
A DRAINAGE DISPUTE WHERE NOBODY COULD SEE THE GROUND.
Two parties, two engineers, and two opposite conclusions about which way the water ran across sixty wooded acres. Neither had measured it — because under that canopy, no camera can.
RETAINED BY
SURVEYOR
INSTRUMENT
AERIAL LIDAR
CONSTRAINT
FULL CANOPY
DELIVERABLE
DEM · 1FT CONTOURS
6 DAYS
TURNAROUND
THE QUESTION
"Where does the water actually go?"
THE CONSTRAINT
Sixty acres of mature hardwood on a contested property line. Both sides had walked it. Both sides had flown it — one with a consumer drone, one with a survey-grade photogrammetry rig. Both came back with a photorealistic model of the top of the forest, which answered a question nobody had asked.
Photogrammetry measures what the camera can see. Under leaf-on canopy, that's leaves. The elevation surface it produces is the top of the vegetation, not the ground — and a drainage argument that turns on eighteen inches of fall is not going to survive being built on tree height.
Both parties had already flown it. Both had photographed the same thing: the top of the woods.
THE INSTRUMENT
LiDAR, flown leaf-off, in early April. The laser fires hundreds of thousands of pulses per second; a meaningful fraction find gaps in the canopy and return off bare earth. Classification separates ground returns from vegetation, and what's left is a terrain model of the actual dirt. Flown with RTK, ground-classified, and delivered as a DEM with one-foot contours — the interval the retaining surveyor asked for, not the interval that made the deliverable look impressive.
WHAT IT SHOWED
The ground fell away to the northeast, not the southeast. Both engineers had assumed otherwise, reasonably, because the visible slope of the tree line suggested it. The canopy and the terrain disagreed by roughly forty degrees of bearing.
WHAT THE DATA ESTABLISHED
A measurable ground surface that neither party had. The surveyor stamped a drainage plan built on the DEM, and the dispute settled without either engineer having to defend an assumption in front of a judge. We acquired the data; the surveyor certified it. That's the whole division of labor, and it's why she called us instead of buying an aircraft
Details anonymized. Locations generalized, parties unidentified, and imagery cropped to remove identifying features. Nothing in this record is specific enough to identify a matter or a property.
MORE CASE FILES
OTHER QUESTIONS, OTHER INSTRUMENTS
COMMERCIAL ROOF · METRO · CLAIM
"IS THE MOISTURE FROM THE STORM, OR WAS IT ALREADY THERE?"
84,000 sq ft flown at dusk for maximum thermal contrast.
READ THE FILE →
RURAL HIGHWAY · WINTER · LITIGATION
"COULD THE DRIVER HAVE SEEN THE STOPPED VEHICLE FROM THE CREST?"
Road reopened in four hours. LiDAR over photogrammetry.
READ THE FILE →
INDUSTRIAL PLANT · METRO · ENGINEERING
"WILL THE NEW UNIT FIT WHERE THE DRAWINGS SAY IT WILL?"
As-built scan of a mechanical room the drawings hadn't matched since 1998