Digitizing the Upham Map
C. Identifying Data to Record from Upham's Map
Digitizing Upham's map involves several different steps:
- Test digitizing: For
demonstration and experimentation purposes, immediately digitize
the points of Upham's map.
- Establish control points:
Simultaneously research information about existing sites depicted
on Upham's map, so that the data created from this map could be
matched to other contemporary data about Salem and Essex County,
Massachusetts.
- Registration of the
map: Use control points to register, or fix, the real world
location of Uphams points, and assigning geographic coordinates to
the image.
- Digitize georeferenced
points: From the registered image, digitize points and
harvest geographic coordinates.
- Adjust locations: Compare
Upham's map to known contemporary data and correct his locational
data as necessary.
- Build and link attribute
database: Link the geographic data to an attribute database
about the participants in the trials to create demographic
mapping.
- Merge data from Upham with data
created from other sources: Georeferenced data will match
with data created from the Pereley/Freeman and Andover Historical
Society maps.
This process is slightly backward from what might usually be
done: that is, we might normally have first researched existing
sites to obtain a series of known "control points" that could be
used to anchor the Upham map as we digitized. However, we
recognized that this would take time and effort, and we felt that
it would be useful to have a point coverage of Salem available to
experiment with, even if it were not "geographically aware," or
referenced to a real-world coordinate system.
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