A closing bit of fun: the classic 1985 Oregon Trail end-game map, rebuilt with Semiotic's GeoCustomChart. Washington, Oregon, and Idaho, along with the forts, rivers, mountains, and the trail itself sit at their true coordinates. Only the palette is borrowed from an Apple II.
Now at: Fort Hall
Every fork in the trail
The map is a line, but the game is a series of decisions. Reconstructing the branch points from the trail's logic: how you cross each river, which way you turn at South Pass, and the last gamble at The Dalles. Here a cohort of 400wagon parties flows west through those forks; a ribbon bleeds off toPerished at the deadliest points.
◄ 400 set out295 arrived105 perished ►
the party’s route lost along the way. Each crossing and route choice is a branch that rejoins at the next fort as a SankeyDiagram.
How it's drawn
GeoCustomChart resolves and fits a Mercator projection to the three state outlines, then hands the layout function scales.projectedPoint(lon, lat) and a geoPath. Everything you see is emitted from one layout: the land asgeoarea nodes (gray fill, black coastline), the Columbia, Snake, and Willamette as line nodes in CGA blue, the trail as a black route line. Carets, forts, START/FINISH plaques, title, and legend as SVG overlays anchored to real coordinates. The wagon rolls along the route by interpolating between the historic stops.
The flow diagram below the map is a plain SankeyDiagram fed the trail's decision graph: forks (the river crossings, the South Pass and Dalles route choices) fan out and rejoin at the next fort, and edgeColorBy paints the doomed ribbons red. Same palette, same screen.
After the MECC Oregon Trail (1985) and Elijah Meeks'sORBISwork on historical geography. Land: US Census state outlines. Not for use as a navigational chart.