I came looking for the same issue.
Although I understand
@Valdo82 's explanation, I still fail to see the usefullness of this bit on information.
Also, I find it very difficult to believe the rating starts at -1250. When you place a ride with nothing around it the score is 0.
Anyway, I know it's not a proper solution, but you could always create a zone over the builging/s + scenery. And the zone info will display the rating. Now, if that information is correct I have no clue.