A Leaflet plugin for drawing colored gradients along polylines. This is useful for visualising values along a course, for example: elevation, velocity, or heart rate. Inspired by Leaflet.heat. Leaflet.hotline works with Leaflet 1.0.3, which is available through NPM, Bower, and GitHub download. Leaflet.hotline needs a browser with canvas support because it creates its own renderer that draws on a canvas element.