The #1 problem with Google Maps, Earth & Streetview images is that the pictures were taken a long time ago. The intersection you received the offence notice may look different.
Google Earth images can be years old.
I read a decision on CanLII with a driver who received a ticket on the 407ETR for driving by a police vehicle with emergency lights at 105 km/hr. He didn't move over or slow down for the cruiser. Because he took pictures months later, that didn't go too well for him.
R. v. Drljevic, 2010 ONCJ 188 (CanLII) http://canlii.ca/t/29w7t
[48] During the course of his examination in chief, the defendant identified and qualified four photographs of the relevant portion of Highway 407, which he took on July 12th, 2009. Even though these photographs were taken approximately nine months after the time of the alleged offence, the photographs were admitted into evidence as exhibit nos. one to four, on the basis that they would be afforded the appropriate weight given their date.
[57] In making reference to photographic exhibits nos. one and four, the defendant acknowledged that the position of his vehicle in the photographs was just an estimate of the location of the police vehicle stopped at the side of the road at the relevant time. He admitted that he did not take the photographs until approximately nine months after the time of the alleged offence and he acknowledged that his recollection as to the purported location of the police vehicle could have been inaccurate.
It's in your best interest to take the pictures yourself.
http://www.ontariohighwaytrafficact.com/topic1765.html