When you are using Google Earth to measure a course, sometimes tree shadows get in the way just when you are trying to follow the SPR around a corner. Then you have to make a guess as to the location of the correct measure line.
Try this: If your corner view is obstructed, go back in time. Google Earth will let you switch back and forth between the most recent image and images from years ago.
I tried this on a shaded corner, and was rewarded with a dandy overhead view of the inside curbline.