Digitization: day 2.
Download just a few more shapefiles from this link
Assemble into 9 groups.
- Download one of the maps for the day:
- Reload your QGIS setup.
- With ‘on-the-fly’ reprojection enabled, change your default CRS for the projection to “Google Mercator”. (You can do this by typing “Google” into the search box;
- Add the two new layers you downloaded in section 1 (‘streets’ and ‘buildings’).
Georectify the map
- Enter georectification mode (under QGIS 2.14 “Essen”,
raster menu -> georeferencer).
- Click the add raster button.
- Set points at street intersections by clicking the add points button.
- Choose a transformation type (use ‘polynomial 1’).
- Choose a name for your output file.
- Make sure the desired output is also in the Google Mercator projection.
Comparing to tabular data
Each group choose a page from this site. View as list. Group 1 should take file 1; etc.
Everybody in your group should trace the outline of a different house on your map.
"layer" -> "New Layer". This will be a polygon layer.
- Right-click or control click on the layer for “toggle editing.”
- Click the green object with the ‘add star.’.
- Draw around a polygon.
- We could add metadata around this point. We won’t, now, but something like this could form the kernel of someone’s final project…
Note on Sources
You may at some point want to work with a larger set of buildings, maps, or streets. Here are links to the original sources.
Another is a set of road outlines in the city of Boston from the Commonwealth of Massachusetts.
Finally, we’re using a set of digitized atlases from the Commonwealth of Massachusetts..)
The census images are from familysearch.org. The proper blocks are found using tools on stevemorse.org.