How, when dragging a block (drag & drop), how to find out if we got inside the svg outline?

Question

css

There are svg-shki, let's say the contours of countries. And separately there are blocks (stupidly rectangles). Question. When dragging blocks (using drag & drop), how to find out if the block is in the svg-frame (in its contours, inside), and what percentage exactly is it?

Answer 1