1 — Focus on the chosen area, then trace a rectangular zone with two markers.
2 — You can add a marker by clicking anywhere on the map.
3 — Hit "Get data" to retrieve elevation data using default settings.

Save Contour Map as an SVG file

If you want to have the contour maps as an individual layer (e.g. to create overlays) you can copy the code underneath the image below and save it as an svg file. Please note, as for now, the drawing below is square and you may want to stretch it to cover the actual area in a map.