This tutorial is designed so you can practice the skills you learned in the Programming Historian QGIS Tutorial “Geo-referencing in QGIS”
- [Note for future work: Each time you install a new version of QGIS, be sure to activate the Georeferencing toolbar in that installation]
- Open a new project; set the CRS by typing 3081 in the filter box and choosing “NAD83 / Texas State Mapping System”
- Set up your modern georeferencing ‘canvas’
- Add Vector and load StratMap_County_poly.shp [a modern shapefile] to serve as georeferencing canvas.
- Add Vector: txdot-2015-city-point_tx.shp
- Add Vector: txdot-2015-city-poly_tx.shp
- For all – change the “properties” so they are not solid. Turn “labels” on for one of the city files [you may have to use both of them]
- Download an 1800s map from UTA’s Cartographic Connections website: http://libguides.uta.edu/ccon
- Use your image viewer software [ie Microsoft Picture Manager] to convert the JPG file to TIFF
- Use the georeferencer to add the TIFF version as a raster layer and add 6 or more control points
- Use manmade boundaries, not coastline or rivers which can change
- Use large cities, ports, or military bases that would have had precise lat/long readings in the 1800s
- Have at least 3 in the western part of the state
- Have more than 3 in the eastern part of the state, in heavily populated areas
- Specify transformation settings
- Compare geo-referenced map to modern shapefile
- Possible: create new vector layers to capture data on the old map
Data sources for this tutorial
- Basemaps: https://tnris.org/maps-and-data/ — search for political boundaries
- Historic maps: UTA’s Cartographic Connections: http://libguides.uta.edu/ccon
How to Convert map-image files
- From JPG to TIFF: Most image viewers will do this. For PC, use www.irfanview.com [pc] or Microsoft Picture Manager
- From SID to TIFF; irfanview can do this; search the web for other utilities
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