measuring distance on OS maps is pretty straightforward key thing to remember to start with that any distance across a grid Square from one side to the other is always one kilometer no matter how big the grid square is is always 1 kilometer now if we want to measure say I want to measure from this pub to this pub and know how far it is so as the crow flies I can take my bit of paper here take it directly over to the pub so I'm making sure that my edge of the paper is there and I'm going to this point here I can take that then to my scale at the bottom and I can see it's going from the edge there is one kilometer to there and there it's not quite 2 so I'm going to go slightly more accurate I'm going to go down to here and it's 9/10 of the way across so I know that the distance as the crow flies between those two pubs is 1.9 kilometers now what if I wanted dough to drive from that pub to that pub how far would it be well that's when we use the edge the paper and we follow the road and the key here is that I'm going to make my paper follow all the way along the road along here up to the top and then down there and watch harriday so I'm going to start at the pub and where my bit of paper moves away from the road I hold it down with my pencil and I move my paper so there are lines with the road and then I follow the road as long as I can where it is next to the paper and then when Road moves away from the edge of the paper I move the paper to line up and then when I lose it I do it again on the corners you'll have to put in more turns than on the straighter bits and in a minute we've got to turn right at this road so it's gonna need a big turn of the paper you're down here but this last bit is really straight and it's down to here just check them in the right place and they're not quite in the right place it's there it's the final final mark that's needed so again I will take that to my scale and then I've got two kilometres to here and then a little bit so I'm going to work that out by moving it down onto the final bit of the scale and then I've got mm it's gonna fall in the middle I think so we've got one two three four five and a half so 5.5 so the total is going to be two point five five kilometres so to get from that pub to that pub directly if you're going to fly there will be one point nine kilometres but if you're gonna drive there along the road is going to be two point five five kilometres