thumb|right|350px|Alpha 2000 analytical stereoplotter. thumb|right|350px|Kelsh projection stereoplotter.
thumb|right|350px|Alpha 2000 analytical stereoplotter. thumb|right|350px|Kelsh projection stereoplotter.
A stereoplotter uses stereo photographs to determine elevations. It has been the primary method to plot contour lines on topographic maps since the 1930s. Although the specific devices have advanced technologically, they are all based on the apparent change in position of a feature in the two stereo photographs.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).