The measurement

Each pixel row in the frame corresponds to a known angle below horizontal, from the gimbal pitch and the camera's field of view. With the camera's height above the building's pad known, the angle to the top of the wall and the angle to its foot give the wall height directly. The method is a ratio, so gimbal and altitude errors largely cancel.

Eave height and the grade

The number measured is the eave height: Top of building (eave or parapet) down to Ground Level, from outside. CBRE, Cushman & Wakefield and Colliers grade industrial buildings on clear height, the distance inside from the floor to the underside of the roof structure, which is always lower than the eave. So the tool reports a height ceiling, the highest grade the eave still allows, never the grade itself: an eave under a grade's minimum rules that grade out; an eave above it only leaves the grade possible. Minimums used: CBRE Super Prime 13.7 m, Prime 10 m, Secondary 8 m; Cushman & Wakefield Super Prime 13.5 m, Prime 10 m, Secondary 8 m; Colliers Class A 30 ft (9.14 m), Class B 20 ft (6.10 m). A ceiling is given only once three frames agree, and where PRISM already records a grade the height rules out, the result says ◆ Grade conflict.

Where the ground level comes from

The Queensland public terrain model (bare earth, half a metre). The camera's height above the pad is its height above the takeoff point, corrected by the terrain difference between the pad and the takeoff point, so no geoid constant is involved. If the pad straddles a terrace edge, or has no coverage, the tool refuses.

Priority properties

Every frame is placed on the map and matched to the PRISM list. The badge on the image and the ★ on the film strip say whether you are looking at a priority property and which address. A measurement within 100 m of a priority property is attached to it and filed automatically into that property's folder in Drive, State / Postcode / Property, with a CSV, a summary and an annotated proof image per measurement.

Library

Clips group by state and postcode, category, month or aircraft; every group collapses. Tick clips to set a category, add tags, export or remove them together. Click a building's name in Results to rename it; renaming to an existing name merges the frames.

Shortcuts

← → previous / next frame · S save · U undo · C clear · F fit · B best frame · wheel zooms, drag pans