Activity 4 of 5

3. Georeferencing

Understand the value of georeferenced maps and how to start using them in a GIS project.

2 min read
  • Understand why georeferenced maps can be useful when asking and answering spatial questions
  • Understand how to find georeferenced maps to use in a GIS project
  • Find out how to take next steps in using information from paper maps in a GIS project

In class activity

What is georeferencing?

  1. Visit Atlascope.org, search for a place in Boston or Cambridge you are interested in exploring on a historical map, and get a sense of the value of georeferencing historical maps by toggling between different georeferenced map layers.

How to search for Harvard Maps that are already georeferenced

  1. Visit the Harvard Geospatial Library (HGL).

HGL Search

  1. Click the Search button.
  1. In the left-hand side facets, under Institution choose Harvard and under Format choose GeoTIFF.
  1. Click on some results. Select Click to Wake on the map to see the georeferenced map layer.
  1. Notice the Download GeoTIFF button which gives a file that will work in QGIS.

Demo and explore more

Sample data

You can download and explore sample datasets related to this activity from the workshop data homepage, hosted on the Open Science Framework (OSF.io)

  1. Visit the workshop data homepage.
  1. Click the three vertical dots icon and select Download. OSF data download page
  1. The folder that downloads to your computer contains sample data from all the workshop activities. It is a zipped or compressed file. In order to use it, you will have to double-click it on Mac or right-click → Extract or Uncompress on a PC.

4. The sample data for this activity, Activity 3 is in the folder activity3_georeferencing. In this folder you will find the following files:

Follow-along steps

  1. Search in HOLLIS using the term “Massachusetts” making sure to filter for Library Catalog and Location = Harvard Map Collection.
  2. Any map that says Online Access can be georeferenced in a web browser. For the class demo we will use the map Map of Massachusetts : exhibiting the Representative, Senatorial and Councillor districts.
  3. For the class demo we will georeference this map using AllMaps, a tool for georeferencing maps from library collections in a web browser.
  4. If the scanned image of the map is not streaming online via HOLLIS, you will need to obtain a hard copy of the image on your computer and use QGIS to georeference it. The sample layer included with this activity, G7625_1897_W2.tif is an example of this process.
    Make an appointment ; Georeference with QGIS.