I enjoyed Michael Pallamary’s story about surveying along the U.S./Mexico border [“The Unforgiving Boundary,” December 2010].
enjoyed Michael Pallamary’s story about surveying along the U.S./Mexico border
[“The Unforgiving Boundary,” December 2010]. He’s been surveying almost as long
as I have, and I applaud his foresight in taking a few extra minutes per job to
extend and fortify a good control net. I do, however have to comment on one of
my pet peeves--precision and significant figures.
Michael states that Mount Tecate “peaks at
Really????? Michael, have you really located the top of that peak within three
ten-thousands of a foot? If you have a GNSS instrument capable of that
precision, where can I buy one?
I have been surveying boundaries for 46 years, and precise measurements have
damn little to do with it. I’d rather do without my EDM and GPS than my shovel
and the old documents I’ve found.
--Jerry (submitted by e-mail)
The author responds: Here in California, it is not uncommon to publish seemingly
precise values of certain places as a play on the outdoor sporting activity
known as geocaching. Searching the location referenced in my article either
from a surveyor’s perspective or as a geocacher would reveal a standard NGS
horizontal control disk stamped “TECATE 2 1935 1974.” It is located 59.5 feet
south-southwest of a prominent lookout tower, 36.3 feet north of an east-west
chain link fence and 20.4 feet northwest of the northeast corner of a large
concrete and rock water tank. The coordinates you commented on were established
by classical geodetic methods and adjusted by the National Geodetic Survey in
June 1996. The California State Plane Zone 6 values as of the 1991.35 epoch are
545,867.177/1,958,798.225 in meters and 1,790,899.23/6,426,490.51 in feet. The
UTM values are 3,604,710.180/529,208.659.
--Michael J. Pallamary, PLS,