View Single Post
Old May 6th 09, 06:34 PM posted to uk.rec.walking
Bill Grey
external usenet poster
Posts: 1,117
Default OS map 5m contours

In message , Phil Cook
Dominic Sexton wrote:

In article , Mike Mason
Just been setting up a walk near New Radnor for tomorrow and noticed that in
the area contour lines seem to be in 5 metre intervals rather than 10 metre
intervals. I've never seen this before on an OS map. Does anyone know of
other areas where the contours are mapped at 5 metre intervals and is there
any particular reason for this.

I think it is just where the sheet is generally not very hilly. In
relatively flat areas 10m contours would mean almost no contours!

When I first noticed two adjacent bits of mapping with different contour
intervals I initially thought there was a very steep sided valley
nearby. Turned out the 5m contours made it look that way until I looked

Here is that example just to the east of Black Hill in the northern Peak

I don't think you would get adjacent areas on an actual OS printed
map. I think it either one thing or the other.

However, is it me or are the 5m contours on that example just
interpolated from the 10m ones which show rather more detail? I don't
think the character of the ground changes from crinkly to smooth
between the 10m contours on Great Hill.

I've only briefly glanced at this page - it may answer the question.
Bill Grey