----------------------------Original message----------------------------
Reply by         : Gregory F. Durocher@Alaska@RMMC
Date             : Friday, May  3, 1996 15:31:14
Reply to         : iSMTP@RMMC1@Servers[<[log in to unmask]>]
Reply:
 
You are correct: the numbered circles on the provisional series maps are the
centers for the aerial photography used in producing the map.  The number to
the left of the hyphen is the roll, and the number to the right is the frame.
 
Greg Durocher
USGS - Earth Science Info. Ctr.
 
   -------------------------- [Original Message] -------------------------
 
To         : "Multiple recipients of list MAPS-L" <[log in to unmask]>
From       : Ken Rockwell <[log in to unmask]>
Subject    : Obscure symbol on provisional topos
Date       : Friday, May 3, 1996 at 1:22:32 pm MDT
------------------------------------------------------------------------------
 
----------------------------Original message----------------------------
A patron asked me the meaning of a symbol on a provisional edition
of a topo sheet, and I didn't recognize it.  It looks like
"crosshairs," i.e., a circle divided in four, and it occurs in
various places on the map.  Next to each one is a hyphenated group of
numerals, such as 1-112, 2-27, etc.  My guess is that it has to do
with the sequence of aerial photos used for surveying the area, and
that they'll gone if the sheet is published in its final form.  Is
this correct?                  -- KR
 
 
 
Ken Rockwell
"Just another map librarian" at
Marriott Library
University of Utah
Salt Lake City, Utah
 
"Without Geography--you're NOWHERE!"