I'm completely new to all this.

I'm trying to make a map of Han dynasty-era China for a mod for a game called Crusader Kings 2.

I've downloaded QGIS and Natural Earth 2, but I need this image to align with the rest of the map so I can use it as a guide for province boundaries.

I tried georeferencing the image, and I managed to get it added as a layer, but even with on-the-fly projection conversion, QGIS refused to show it at the same time as any other layer.

This was the result.

I'm also open to suggestions on any simpler methods I could use if QGIS is overkill for what I'm trying to do.

  • Welcome to GIS-SE! By "the program refused" do you mean "QGIS refused" or "Crusader Kings 2 refused"? – PolyGeo Jul 19 '13 at 2:54
  • QGIS refused to show the layer with other layers. With some fiddling, I managed to get this: i.imgur.com/acfFDZU.jpg but as you can see the map features don't match the points although it's much closer than the original. – Craig Jul 19 '13 at 2:59

I have not georeferenced using QGIS but I found a tutorial that says:

In QGIS there are several methods for transforming the image, these include the linear / affine transformation, the Helmert, the 1st, 2nd and 3rd order polynomials, and the thin plate spline. These different Transformation Methods interpret your Control Points in different ways, and control how the map you are georeferencing is fitted and warped to your georeferenced base map.

For best fit, the thin-plate spline or higher-number polynomial transformations are often best. The spline transformation, as a true rubber sheeting method, transforms the source Control Points exactly to the target Control Points, and optimises for local accuracy opposed to global accuracy.

I think you will get best results using a true rubber sheeting method (i.e. spline).

  • 1
    i.imgur.com/CoTDSfO.jpg This is what I've managed to get with your advice, using spline instead of linear. Thanks so much. – Craig Jul 19 '13 at 5:33
  • 1
    Excellent - it's nice to see the result! – PolyGeo Jul 19 '13 at 5:58
  • As a side matter, it's also nice to see the formation of major river deltas, too! @Craig – Martin F Jan 13 '14 at 19:39

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