How to

Here's how it works:

Step 1

Find and upload a raster image of a known geographical location, preferably in high quality.

Upon upload, give a meaningful title and how far in want to be able to zoom during georeferencing.

Step 2

Find landmarks, like places or streets, that are present in both maps and whose location has not changed.

Pick those "ground control points" on both maps respectively and hit "Save control point".

Step 3

When at least 3 control points have been selected, a button "Overlay map" appears.

When you press it, your uploaded map appears superimposed on the OSM.

Hints:

Please note that in order to display large image efficiently, they will be tiled and uploaded to a CDN, which may take a little while (usually 1-2 minutes)

You can check how well the image is aligned by using the opacity slider!

If the overlay map lacks precision, it's usually due to imprecision during georeferencing.

You can always edit existing control points by selecting them and adding more can enhance precision.