A variscale is variable length mechanical scale (ruler) designed to directly measure
latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
and
longitude
Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...
on
USGS
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...
maps.
[Roos, M., 1967. Variscale stereo point marking instrument, Photogrammetric Engineering, 33(11):1260-64.]
References
External links
Instructions for using the Variscale
Measuring instruments
Cartography
{{Cartography-stub