Geographic Information Systems (GIS) and remote sensing image processing technologies were used
to explore and analyze the spatial and attribute information at Birchtown. These tools were also used
to geo-correct the only known copy of a late eighteenth century land grants map of Birchtown,
known as the Goulden Map.
Geographic Information System (GIS) - The Black Loyalist Heritage Society manages their geographic information with Arcview GIS 3.2.
As well, they have acquired the Image Analyst extension which is used to georeference modern and historic aerial photographs and geocorrect historic maps, such as the Goulden Map.
Arcview GIS 3.2 enables the integration of archaeological site locations with artifact catalogues, aerial & site photos, georeferenced historic maps, modern base data, and soon, genealogical records. As well as being an excellent information management tool, the GIS is also a primary
research tool for the analysis of the archaeological data. return to top
Remote Sensing - Remote sensing data and technologies used at Birchtown include modern true colour and historic black and white vertical aerial photographs at scales of 1:10000 and 1:15840.
As well, polynomial transformations (2 dimensional) were used to geometrically correct the Goulden Map, as opposed to orthocorrections (3 dimensional).
In the course of research, it has become our opinion that orthocorrections are entirely unsuitable for historic map georeferencing as the levels of distortion required to fit the historical data to modern, geometrically accurate base data is variable across the image. Orthocorrection algorithms (and hence software)
are suited to modern geographic images that have been acquired according to modern geometric standards. return to top
Software - The geomatics applications at Birchtown have used ESRI GIS software, including Arc/Info and Arcview. Image processing of the Goulden Map was performed with
PCI Geomatics' Easi/Pace software, which is now part of the Geomatica software package. Future image processing will be carried out with the Image Analyst Extension for Arcview GIS 3.2. return to top