The Curvimeter is the perfect tool to measure curved lines on a map. These devices go by a variety of names: opisometer, meilograph, or simply a map measurer, but the idea and component parts are the same: a convenient handle, an indication face, and a small wheel to roll along your map route. Learn how it works by assembling the Curvimeter from the Ugears STEM-Lab collection. https://ugearsmodels.com/curvimeter.html | Ugears