Building the Salem Witchcraft GIS

Digitizing the Upham Map

F. Determining Real World Coordinates: Overview

The "quick and dirty" digitizing detailed thus far allowed us to experiment with constructing some simple demonstrations and tests to determine the usefulness and feasibility of various types of display.

While this proceeded, we began to research information about those sites known still to exist. The plan for locating control points, matching them to Upham's map and transforming the data to match real world data was as follows:

  1. Obtain base geographic data for area.
  2. Identify those sites on Upham's map which still exist.
  3. Research locational information on those sites.
  4. Obtain locational data and convert to GIS data formats.
  5. Overlay above with base data.
  6. Modify locational data as necessary to create control points.
  7. Match existing data to control points and transform data.