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When trying to determine Alex's elevation from my topo map, I found it a bit
confusing.  The major contour lines are at 50 ft elevation intervals.  If I
recall those are always 5 units apart, so minor lines are at 10 ft
intervals.

When one gets near the river valley, with a drop of 200+ ft in a quarter
mile on the West Lafayette side, they are packed together, often less than a
millimeter apart.  Once out of the valley, the 700 ft line can meander along
for 4 or 5 miles (radius), with small 700 ft shapes within.  The problem
then becomes determining whether the minor lines between the 700 ft lines
indicate a rise or fall.  It is not as easy as determining what is happening
as when the "circles" are more or less concentric like isobars, or seeing
valleys, ridges, or saddles.

In some cases minor lines that extend for many miles will be labeled once
(690, 680, 680, etc.)  Problem being that one tag on a line with 10-20 inch
length that passes through residential and commercial areas, roads and
highways etc. and converge with other minor lines so it is almost impossible
to track one to the area of interest.

There are very few small areas marked with the depression cross lines.  Any
tricks or tips, other than the old mach-one eyeball on site on how to
interpret what is happening?

Thanks

Bill


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