Figure 1 - Landsat 7 ETM+ Image of the Guelph area

 Figure 2 - Landsat 7 ETM+ Image of the Hamilton area
 

 Figure 3 - Landsat 7 ETM+ Image of the Toronto area 

These thermal images were remotely sensed by the Landsat 7 satellite. Launched in 1999 on the Delta II 7920 carrier rocket, the satellite passes over Ontario once every 16 days at an altitude of 705km and has a swath width of 185km. Landsat sensors have a moderate spatial-resolution. You cannot see individual houses on a Landsat image, but you can see large man-made objects such as highways. This is an important spatial resolution because it is coarse enough for global coverage, yet detailed enough to characterize human-scale processes such as urban growth.
 
Thermal images are obtained through the infrared signature of an object surface. The pixels on these thermal images are 60m and 120m in size. Because of cloud cover and other inconsistencies, rather than using a single image, we amalgamate images over the course of a summer to get a more balanced average temperature. The use of these images has been made possible through Natural Resources Canada’s Earth Sciences Sector.