Harry Wyeth <[EMAIL PROTECTED]> wrote:
> Subject: [USMA:14697] Contour lines
> Date: Mon, 30 Jul 2001 09:46:38 -0700
> From: Harry Wyeth <[EMAIL PROTECTED]>
> To: U.S. Metric Association <[EMAIL PROTECTED]>
>
> There has been some discussion about contour lines. From the
> standpoint of
> one who does a fair amount of backpacking and mountain climbing, 10 m
> is
> much more useful. It is also pretty close to the standard 40 ft
> contours
> that appear on thousands of USGS topo maps. Doubling that gives one a
> map
> which doesn't display much useful info to a hiker. Lots of gullies and
> cliffs can hide within a 20 m elevation change.
>
> HARRY WYETH
Back in the 1970s and 1980s, the USGS made a BUNCH of 'all SI' 1:25000
topos covering Massachusetts and parts of other states in the
northeastern USA, as well as numerous 'all SI' 1:24000 maps from
elsewhere in the USA. Their contour intervals were typically 3, 6 and
12 meters (depending on the steepness of the terrain that the individual
maps cover).
I agree, though, except for the very most RUGGED areas, 10 meters is as
far apart as they should be. There ARE some standard USGS 7.5 minutes
maps that DO have '80 foot' contours, though, but again, the terrain
that they cover is EXCEPTIONALLY steep and rugged.
I would go with contour intervals (depending on steepness of terrain) at
1, 2.5, 5, 10 and, for only the very steepest terrain, 20 meters
N
--
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Regards,
Michael G. Koerner
Appleton, WI
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