[Qgis-user] Building Historical Maps

[James Cobban]

I am running a project to present historical information about Ontario, 
Canada.  To support this I have imported GIS information on 
administrative boundaries from the Ontario Government.  The only problem 
is this information only describes the current administrative 
organization of the province, not the organization it had for most of 
its history up until the early 1990s when the system was 
"rationalized".  I am looking for suggestions of how to extract as much 
information from the current GIS data as possible.

For example:  From 1850 to the early 1990s most of Ontario was 
administered as counties with lower level townships.  In the 1990s the 
more urbanized portions of the province were reorganized as "Regional 
Municipalities" which largely ignored the old county boundaries either 
by including only the urban portion of a former county, or by 
incorporating urban portions of multiple counties. So, for example, if I 
wish to reconstruct the boundaries of the former county of Welland I 
have to concatenate the boundaries of the individual townships that made 
up the former county, and then remove all of the internal, and 
redundant, boundaries.  I have manually done that for one county but it 
was a pain in part because the polygons of the individual townships did 
not begin at a "corner" shared with an adjacent township within the 
county. Just finding exactly where the polygon began and which direction 
it went took time.

The second issue is that boundaries changed multiple times over the 
period between 1763 when Britain assumed control of the area of Ontario, 
and the present.  In particular city boundaries change as areas are 
transferred from the surrounding rural municipalities to the city as a 
result of urban growth.  Where do I get the old boundary information 
aside from tracing them from old maps?

-- 
James Cobban
911-500 Springbank Dr
London, ON, Canada
N6J 4G6
mailto: webmaster at jamescobban.net
+1-226-504-7603