Tor Ratings:

Each tor is given a five star rating in order to give some idea of how easy or difficult it is to reach. A one star tor is dead easy to get to, while a five star one will be extremely isolated and not without a certain amount of risk. Only attempt the 4 and 5 star tors if you know what you are doing, have all the right kit, and don't plan on blaming me if you get lost.

If you must know, the database expression for assigning the rating is:

Round(10*([Distance_From_Car_Park]*(Abs((1000+[TorElev])-[CPElev])))/7109.3,2)

[Distance_From_Car_Park] comes from the following expression:

Round((Sqr(Abs([Tor_Easting]-[EastingCP])^2+Abs([Tor_Northing]-[NorthingCP])^2))/1000,2)

...which is pretty straightforward Pythagoras.

I add 1000 to the tor elevation in order to prevent the situation where [Distance_From_Car_Park] is multiplied by zero, which will occur if the tor and car park are at the same elevation. This also weights the rating towards height gain rather than horizontal distance, which I believe to be a more important factor.

7109.3 is one thousandth of the maximum value for [Distance_From_Car_Park]*(1000+([TorElev]-[CPElev])), which just happens to be from Brousentor Farm car park to Cut Hill. This is there in order to get a relative value out of ten, Cut Hill being the most isolated place on the moor, as far as I can tell.

Values from the above expression relate to stars as follows:

0< >2
2<= >4
4<= >6
6<= >8
8<= =>10

Anything above 10 is not rated, although I may code in a fuzzy upper limit depending on some other factors at a later date.