topojson-simplify

One task where GeoJSON falls down is simplification of a group of polygons with common boundaries, e.g. the 48 conterminous US states. If you start with a highly detailed set of polygons, you need to simplify them for practical display in an online map. GeoJSON doesn't encode the fact that the boundary points are common between adjacent polygons. When you simplify those polygons, each one is handled separately, and you end up with "slivers" where the boundaries are misaligned: https://www.bing.com/images/search?q=map+slivers+betwen+poly... TopoJSON solves this by encoding each such boundary only once. So when you simplify the polygons, they are all done together, and the same simplification applies to adjacent polygons. No more slivers! https://github.com/topojson/topojson https://github.com/topojson/topojson-simplify

You could try to reduce the size with TopoJSON https://github.com/topojson/topojson-simplify https://medium.com/@mbostock/command-line-cartography-part-1...