in brief: with multi-page georeference atlases, you need to trim the margins of overlapping sheets, and OldInsuranceMaps.net has a really nice way of doing it. Complete with snapping and (now) vertex styles that make it easy to clean things up

From some recent activity, here's a rare but good example (from Worcester Mass.) of where the Thin Plate Spline transformation makes sense for #georeferencing #sanborn maps. Curved roads out in space are sometimes drawn without good scale and need extra distortion oldinsurancemaps.net/layer/72727