Using the Map Collections
Maps: Frequently Asked Questions
Air photo scale. How
to determine?
Altitude divided by focal length = scale. For example 10,000 ft (x 12)
/ 24 in. = 1:5,000
Lake Depth, How to determine?
Some navigable lakes, e.g., Tahoe, are covered by a US NOS nautical chart.
If the lake is in a park, forest, etc. the ranger office for that particular
area probably knows the maximum depth. For resevoirs, if you have a map
that shows the maximum pool elevation of the surface, you could subtract
the elevation at the base of the dam for a rough estimate of maximum depth.
Compare differences in coutours at the dam base versus those on the lake
shore. Consult commercial fishing map of the lake (these frequently show
isobaths). Look at old editions of 7.5 or 15 minute USGS topo maps that
show reservoir before it was filled (remember, though, that the lake may
have silted in since it was filled). Source: Mark Thomas
(e-mail to MAPS-L May 8, 2000) and Phil Hoehn
Magnetic Declination, How to determine?
Topographic map sheets and aeronautical charts usually contain this information.
Try also the following web site:
Photocopies, How can I obtain?
Branner Library has self-service photocopy machines (8.5 x 11, legal,
and engineering (36 inches wide by any length)). Other information, including
that for remote users, is available at:
Stanford Geoscience Maps: Access & Circulation
Maintained by Julie Sweetkind
Last modified:
June 22, 2005
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