Each continuous in-Ontario network starts at zero kilometres at its downstream provincial-border crossing or receiving-water shore. One linear distance counter controls every network. Fill and reverse animation are clipped to Ontario, and outside distance is excluded. Outside routes are shown only during the drainage fact.
Data notices and attribution
HydroRIVERS omits many small streams. The longest-river highlight compares connected river lengths within this dataset under the stated shoreline and provincial-boundary definitions.
Each region uses a data file containing boundaries, receiving waters, river connections, upstream distances, labels and factual annotations.
Additional regions require their own river data and endpoint definitions. Boundaries can use administrative areas or custom GeoJSON polygons. The renderer and animation controls can be reused.
Region preparation and export instructions are included with the source project.