--- Begin Forwarded Message ---
Date: Tue, 4 May 1999 11:58:59 -0700
From: Jenny Stone <[log in to unmask]>
Subject: Fw: polyconic projection
Sender: Jenny Stone <[log in to unmask]>
 
 
Greetings. I've got a stumper of a question about USGS historic maps, quoted
below. I can find details on the polyconic projection, as well as the
equations used to calculate the meridian, etc., but I can't find the actual
parameters that were used by USGS in Washington during that time. Does
anyone have any ideas where I might find that?
 
Thanks.
 
Jenny Stone
___________________________________
GIS Librarian * Map Collection
University of Washington Libraries
Box 352900 * Seattle, WA 98195-2900
phone: 206.543.9392
 
-----Original Message-----
 
 
Subject: polyconic projection
 
 
|Jenne,
|I have a question for you related to digitizing a paper map.  The map I am
|digitizing is a 1898 USGS landcover map.  It has a lat/long graticule for
|reference coordinates.  Based on the date I am assuming the map used the
|Clarke 1866 spheroid and the polyconic projection.  I am also assuming a
|local datum, although it is possible it is connected to one of the earlier
|American datums.  From looking at Arc/Info help it seems that I need the
|datum for the map and parameters for the map such as central meridian,
|parallel of origin, false northing and false easting.  Do you know if this
|information is available and/or whether it is necessary.  Thanks for any
|help you can provide.
 
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