Bridges are tagged 1, a culvert or tunnel -1, but is a culvert below a tunnel -2 ? Like a metro system ? And what about two basins alongside each other, but in diffent levels ? Its a polder system, a pump lifts the water up to a certain level, sometimes repeatedly. All water levels the same value, none ? asked 16 Aug '12, 23:21 Hendrikklaas |
if features are really above each other, you can indeed use also higher values. between -5 and 5 is possible. Otherwise, see Circeus' answer. answered 17 Aug '12, 06:40 moszkva ter |