Old maps and plans of France to georeference[edit]
Wikimedia and the British Library are trying to georeference old maps and plans found in the Mechanical Curator collection, a set of 1 million digitised book illustrations from 19th century books. (See here for more information).
Placing these maps and plans on maps of the modern world ("georeferencing") gives them an accurate location and scale, which in turn should allow their ready upload to Wikimedia Commons with reasonably accurate automatic categorisation. An up-to-date index of the maps and plans already georeferenced can be found on the accompanying georeferencing done page. You may also wish to add your name to the Participants list on the talk page.
Maps and plans from other parts of the world can be found on this worldwide status page and completed page, including further maps that may relate to France in books on other index pages.
The basic principle of the georeferencing is to find geographical points in common that can be found in both the digitised image and on a current map. With enough points, this makes it possible to view the old map laid on top of the new one.
To choose a map, use the templated to georef links on the left to see the maps and plans available to georeference for each of the Synoptic index or to do page subject areas.
Then click on any of the thumbnails on the resulting Flickr search page to get to the Flickr page for the image itself; and scroll down to just below the image to reveal a link to open it in the BL/Klokan Georeferencer.
A plan or map can also be selected at random by going to the bl.uk/maps page and clicking on the graphic with an orange background that says "Fix the location of a map". Alternatively, for finer control, the maps and plans available book-by-book can be investigated from the index pages directly.
Once inside the Georeferencer tool, the first step is to log in (top right), creating an account if necessary. By default the tool will open in the "georeference" view, unless the map in question has already been georeferenced. Then (see overview video),
Zoom into the old map enough to read it, and then find the corresponding location on the modern map. Use the gazetteer at the top if necessary. Click on the “This map” tab for more information. (In some cases it may be worth looking at the other half of a double-page image, or even a pdf of the whole book, both available from the image's Flickr page.)
Click on one map to assign a point, then assign a point at the same location on the other map.
Assign as many points as you can over the entire map (minimum of three). Existing points can also be moved around.
If possible, also add a title to the map, using the "Add title to this map" at the bottom left, either from text on the map, or by giving a description of it.
Click the red “Save” button in the upper right to store the points you have added.
Finally you will be asked to draw an outline to define the extent of the map content in the image (see video at www.youtube.com/watch?v=fgS6swzyJeM), finally double-clicking to close the bounding polygon.
Having done this you will then be taken to the "Visualize" tab, showing the old map placed over the new map. Adjustments can continue to be made by alternating between the "Georeference" and the "Visualize" tabs, pressing the red 'save' button after each set of revisions.
Once you are happy, hit the blue "Georeference another map" button to get another map at random; or choose another one from Flickr, as above.
The information added should now be enough to allow the plan to be uploaded to Commons with a reasonable automatic categorisation. (In development).