Mapping the Farmington Canal with Lidar
This map was first inspired by a webinar series created by the Avon Historical Society about the Brian D. Jones Paleoindian Site on the Farmington River. Specifically Prof. Will Ouimet’s lecture “The LIDAR Revolution in Earth Surface Mapping” introduced to me the rich imagery available, and briefly touched upon nearby remnants of Farmington Canal aqueduct and the application of Lidar to the study of the local past. Watch that video for a brief introduction to the technology and its application in archaelogy.
Using the Lidar-based imagery provided by CT ECO and MassGIS, I was able to trace a digital journey along the surviving renmants of the canal using QGIS. The line is currently comprised of over 3000 points, with varying degrees of detail depending on the data.
Terrain imagery can reveal subtle canal works beneath forests and other vegetation, but only a fraction of the route remains visible. Reconstructing the full line required comparing the modern Lidar contours with historic maps and aerial photographs, then using each source to interpret and check the others.
Tracing the Connecticut canal
For Connecticut’s Farmington Canal, two key references were chief engineer Henry Farnam’s 1828 map and aerial photographs taken in 1934, available through CT ECO. The early map establishes the accurate shape of the canal and its towpath line; the photographs capture traces that have since been altered or erased by 20th century (particularly post-WWII) development.
Carl E. Walter’s canal maps add details such as basins and other features. These maps were referenced to shape sections that were missing from Lidar and for checking the accuracy of the completed tracing. Carl’s set of printed maps on the Farmington Canal, and digital database of the broader New Haven and Northampton Canal, are the definitive sources for any research on the canal.
Reconstructing the Massachusetts route
Carl Walter’s map of the Hampshire & Hampden Canal also provided much of the route of the route through Massachusetts and attached feeder canals. This map was impressively constructed from newspaper surveyor notices, since unlike in Connecticut no engineer’s map of the Hampshire & Hampden Canal is known to have survived.
The resulting map on this site is therefore a synthesis rather than a trace of any single source: Lidar supplies the surviving physical evidence, while historic maps, photographs, and Carl Walter’s maps help resolve ambiguous terrain.
A complete list of references and datasets is available on the Sources page.