Another good site for OTA TV information is www.tvfool.com I use this for the USA but it also supports Canada, if you scroll down you can enter a general location province/state city, in the USA I use zipcode. you can also enter the address to get data for your location. General Toronto info is the following link. If you click on "Online TV Maps" on left side you can see a map view. You need to play with the map view a bit to see how it works. If you are in a hilly area your location can make a big difference.
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=1ddae335b1982a
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=1ddae335b1982a