USGS Topographers at Work
![Image: USGS Topographers at Work](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/FA064-300.jpg?itok=TXKMJBuc)
Detailed Description
A USGS topographer works with a leveling instrument. The umbrella prevents temperature fluctuations that could affect the leveling bubble in his instrument. The man on the ground is recording elevation data.
Sources/Usage
Public Domain.