The surveyor's instrument could measure angles to a tenth of a second. Elevation, bearing, azimuth — any direction it pointed, the number resolved.
What it couldn't do was swivel freely. A detent every fifteen degrees, and between the detents, a dead zone where the mount wouldn't hold. So the maps it produced had gaps: wedge-shaped silences, exactly regular, where the terrain went unrecorded.
After forty years, people used those maps to build. Roads followed the measured corridors. Towns grew in the documented sectors. The gaps became forest, became watershed, became the parts of the county where people said nothing's out there — not because they'd looked, but because the instrument had never pointed that way.
A new surveyor arrived with a different mount. Continuous rotation. No detents. She mapped the gaps and found: rivers. A granite ridge. Three foundations from a settlement that predated the county by two hundred years.
She published the complete map. People studied it, noted the new features, and then — gradually, without deciding to — kept building along the old corridors. The roads were already there. The infrastructure assumed the old geometry. Her map was accurate, but the landscape had already learned the shape of the instrument's limitations.
The detents were gone. The territory they'd created wasn't.