Original Columbia County SVG (no simplification)
Naively keep only every 20 points
Iteratively relax the smallest angle until 95% of points are removed (patience, super slow and crappy)
Sort and take out the 95% of points with the smallest angle
Just take 5% random values for giggles
Iteratively invoke the convex hull algorithm on gaps
Convex hull (not a simplification)

Force convex hull in simplification
Point inclusion test (flying dot placed at random y-position)