Georeferencing21.05.2017 12:31 Uhr
Georeferencing in QGIS
- Download this file: http://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~279991~90052930 in at least large size
- Use export button
- Open QGIS Desktop 2.18.6
- Make sure the following plugins are installed: Erweiterungen –> Erweiterungen verwalten und installieren…
- OpenLayers Plugin
- Open a suitable backgound map
- Web –> OpenLayers plugin
- Choose Raster –> Georeferenzierung
- Open downloaded file in Georeferencer window
- Use coordinate system: WGS 84 / Pseudo Mercator EPSG:3857
- Set Transformationsparameter (yellow cog wheel)
- Transformationstyp: try Helmert first
- Ziel-KBS: WGS 84 / Pseudo Mercator
- Ausbaberaster: a TIFF file you can find afterwards.
- Select “Add Point” (small yellow star next to lines meeting)
- Repeat until you have enough points (trial and error):
- find fixpoint on old map, click on it
- choose “From map canvas”
- click on corresponding point on modern map
- Select “Start georeferencing” (green arrow)
- Open resulting file as a layer in QGIS
- Tip: change Eigenschaften: Transparenz
- Experiement with different “Trasformation types”
- under “Trasformation settings” (yellow wheel)
- What are the main differences between a map from 1665 and a modern map?
- mapping techniques?
- the landscape?
- other things?
Try it out in the lab, you can also install QGIS and try it at your own computer: http://qgis.org/
Try also other maps, and compare. Can you find systematic differences in how hard it is?
Georeferencing can be the topic of Hausarbeit.