USGS Topographer at Work
![Image: USGS Topographer at Work](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/FA076-600.jpg?itok=XI3CYFt_)
Detailed Description
A USGS topographer works with a plane table and alidade to create a 1:180,000 scale topographic map near Imlay, Nevada. The umbrella is to protect the instrument from temperature variations.
Sources/Usage
Public Domain.