I can say that the average for height, is 31 pixels. If figured this out incredibly easily by instead of counting the height of each different tile, I could instead find the height of the lawn itself and multiply that by 9. After multiplying it by 9, I would divide it 45 for the whole amount of tiles there. And using the same tactic, I found the average width was 28. (Actually it had decimals I just cut them off).
That doesn't sound like it would work, but that's because it's so complicated and hard to understand. (To find the average hight, you have to use the width...?) I don't see how that would work, but if it does, good job.
I think I see what you mean:
Since it's a lawn, each column is different. So you have to calculate each tile size. Because of this, you decide to find the hight for one column. Then you multiply it by the other columns and divide it by the total, instead of dividing it by the hight of the one column in tiles without multiplying. That way you get the same answer, with more work involved.
As for the other issue, it doesn't matter if tapping on the lawn works. Just make it so that tapping outside of a range (in this case, the area of the lawn) does not do what tapping in it does if that makes sense.
Well I don't know how to help too much because I don't know the details.