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Quality control review process

OldMapsOnline Georeferencer is a powerful online tool that allows users to assign geographic locations to scanned historical maps and help map libraries retrieve important metadata. Once georeferenced, the entire map collection becomes geographically searchable, offering a new way of discovery for researchers, students, and the general public.

To ensure that the maps are georeferenced correctly and the metadata is correct, a review process is used to check the quality of the georeferencing work done.

Steps of the Review process

Assigning the "Reviewer" role

For the review to take place, it is necessary to assign the persons who will have reviewer rights. The project administrator does this setting in the personnel section of the institutional georeferencer project website (in this case,

  1. Log into with your administrator email and go to your institution georeferencer website

  2. Go to menu “personnel” and fill in the reviewer email address

  3. Choose position “reviewer” and then click on “add person”.

  4. Reviewer role is added.

Where to find maps for review

The person assigned as the "Reviewer" will see the "Review" section in the hamburger menu; clicking on it will open the dashboard.

Reviewer dashboard

On this dashboard, you can review a random map or a map from a specific collection. You can also see top reviewers and progress statistics.

After clicking on a review, a familiar georeferencer view appears side-by-side, and the reviewer can review the assigned points and adjust them if necessary. Of course, you can also use overlays, coordinates and, importantly, clip control.

Transformation method

Each map has in Georeferencer under "Coordinates -> Transformations -> Default Transformation" the option to set the transformation method used when exporting rasters to WMTS or GeoTiff.

During the review process, the reviewer needs to decide for each map which is the suitable transformation method for that particular map - make the decision and confirm it.

Once everything is checked and set up, return to the side-by-side page and select “Approve now”. The map is approved, the metadata is saved, and the reviewer can move on to the following map to process the review and approval.

Import into the search portal

Once all maps are reviewed, we recommend importing them into the search portal, where visitors can view maps and collections from map libraries. To import into the search portal, please contact us via email at

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