GEOSTATS: Land-grid to map projection conversions
- I am interested in finding out what are the
various methods people use in the conversion
of locational data from land-survey grids to
map projection units.
In our shop we use a program modified from one
written at the Montana USGS office (but never
published) that calculates latitude and longitude
for a point in the US General Land Office grid
system (township-range-section), based on
digitized corners of townships or sections. The
program can handle a precision of up to 1/1024 of a
section (approximately a square mile), although
the way it handles irregularly distorted sections
is not too elegant.
In order to improve locational accuracy, we are
reformating Arc/Info basemap coverages of sections,
whereas we had used the township corners previously.
The reformatting of the basemap must essentially
be done by hand to extract "sigificant" corners in
I am wondering what others do to convert large
quantities of data points when they are supplied
with locational data like the township-range-section
Except for some references to Kansas Geological
Survey programs from the 1960's, where the land-
grid is much more regular than in is in the western
U.S., I am unaware of other programs that are used
in North America or elsewhere.
Dr. Larry N. Smith 1300 West Park St.
Montana Bureau of Butte, MT 59701-8997
Mines and Geology (406) 496-4379 (v)
Montana Tech of the (406) 496-4451 (fax)
University of Montana larry@...
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