-------- Original Message --------
Subject: (Fwd) Dates on 7.5 min. topo maps
Date: Fri, 24 Jan 2003 10:37:01 -0500
From: "Joan Zeeb-Roman" <[log in to unmask]>
Reply-To: [log in to unmask]
Organization: Kent State University
To: [log in to unmask]
CC: [log in to unmask]

------------------
Dear MAPS-L subscribers,

I recently had a few questions about dates on 7.5 min. topo maps.
The reply that I received was very good, so I thought that I would
share it with the list.  It was written by John Conroy of the NMP
Standards Team, USGS/Mid-Continent Mapping Center.

Joan Zeeb-Roman

------- Forwarded message follows -------
Subject:                Dates on 7.5 min. topo maps
To:                     [log in to unmask]
Copies to:              "Robert A Bier" <[log in to unmask]>,
        "Robert E Rinehart" <[log in to unmask]>
From:                   "John B Conroy" <[log in to unmask]>
Date sent:              Wed, 22 Jan 2003 15:44:57 -0600

Hello, Joan.  I've been asked if I would answer your questions.  I
don't blame you for being confused because in order to understand the
dates on our maps, it requires some information about our map
revision
types that most people are not aware of.  I've tried to summarize it
as briefly as I can below but, as you will see, it gets a little
complicated.

The USGS has done 7.5-minute mapping since about 1908 but it didn't
become the base map series until about 1950 (before that, the
15-minute map series was the base map series).  Most of the revision
of maps up until the end of the 1960's involved field checking and
contour revision.  In 1969 the USGS began updating maps using imagery
and ancillary sources (photorevision maps).  New features and
modifications of previously mapped features were shown in purple on
these maps.  Planimetry (roads, buildings, drains, etc.), boundaries,
and names were updated during photorevision, but there was no field
checking and contours were not updated.  There were other kinds of
revision mapping going on at the same time, but these involved field
checking and contour updating.  We stopped making photorevision maps
in about 1994.  We no longer have a permanent field crew to check map
detail, so we have prepared only a few field checked maps during the
last five years (complete revision).  However, we continue to update
maps from imagery and ancillary sources (basic revision).  Although
basic revision maps are not field checked, new and modified detail is
added in one of the five basic colors (red, blue, brown, green, and
black), and contour revision is an option that that a cooperator can
pay to have done.  Since 1993, if our map supply is low and a
photoinspection has indicated that a revision of map detail is
unwarrented, we have updated the collar information, boundaries,
names, and corrected known errors on maps (minor revision).   (See
the
end of this message for more information on minor revision maps.)

The imprint date on our maps is the year the map was printed.  The
imprint date is changed whenever anything on the map is changed
(including complete, basic, and minor revision).  The imprint date is
not changed when a new supply of maps is reprinted to replenish
dwindling map supply.  The people who maintain our stock of maps in
the distribution center in Denver use this date to determine whether
or not they should retain the maps already on the shelves.

We have used different methods for deriving the map date (the one you
call the "edition date") over the years.  Until 1977, the map date on
7.5-minute maps, other than photorevision, was the field check date.
On photorevision maps, the original date was retained, but the date
of
the revision photography was added in purple below the previously
published black map date.  In 1977, the map date of revised maps,
other than photorevision, became the year the map was edited.  We
continued to use the revision photography date for the purple map
date
on photorevision maps until about 1980, at which time it was also
changed to be the same as the map edit date.  In 1994, we resumed
using the year of the field check (on maps that are field checked) or
the year of the imagery source (on maps that are not field checked)
for the map date.  On minor revision maps, the map date is the year
of
the inspection photography.  On maps prepared by the USDA Forest
Service according to USGS basic revision guidelines, the map date is
the more recent year of either the Forest Service correction guide or
the revision imagery.

On field checked maps, the difference between the map date and the
imprint dates is due to production schedules, shelf time, and map
finishing efforts.  On non-field checked maps, the date of the
revision imagery also has to be factored in; even with our more
efficient revision procedures, if the revision imagery source is
three
years old at the time the project is authorized, the difference
between the two dates on the new updated map will be at least three
years.

A checklist of our minor revision procedures can be viewed by going
to
our standards web site at http://mapping.usgs.gov/standards/,
clicking
on Primary Series Quadrangle Map Standards, scrolling down and
clicking on the pdf icon for Part 2: Specifications, Standards for
Revised Primary Series Quadrangle Maps (
http://rockyweb.cr.usgs.gov/nmpstds/acrodocs/qmaps/2rqm0602.pdf), and
going to Appendix 2-K: Minor Revision Procedures (page 249 of 261).

I hope this helps.  If you need more information, please don't
hesitate to contact me.

John Conroy
NMP Standards Team
USGS/Mid-Continent Mapping Center
1400 Independence Road, MS 523
Rolla, MO 65401
(573) 308-3804
[log in to unmask]

----- Forwarded by John B Conroy/NMD/USGS/DOI on 01/22/03 03:43 PM
-----



Dear Mr. Bier,

I had talked with you last year on this topic (Dates on 7.5 min. topo
maps, specifically, the printing date).  You provided me with alot of
information.  I was explaining the printing date to one of our
employees today and a few questions came to mind.

1.  You had said that if minor changes are made on a map, that they
issue a new map and change the printing date, instead of completely
redoing the map.  What constitues a minor change--what kind of
changes?  I think you had mentioned something about that if the
actual
physical topography is changed then they completely redo the map.  If
you could clarify this, that would help.

2.  You had said, I think, that when they issue a new map with a
minor change and change the printing date, that they change the
collar, too.  Is that right, or did I get that wrong?  To me, it
wouldn't seem that they would ever need to change the collar.  And,
am
I right in my understanding that the collar is the grid numbers
around
the map.

3.  Also, usually the printing date and the edition date differ by a
few years.  Example:  Calistoga, CA 1997 (the printing date is 1998).
Sometimes, these dates differ by as many as 5 or 6 years.  Why is
this?

Thanks for your help!

Joan Zeeb-Roman

_____________________
Joan R. Zeeb-Roman
Map Library
Kent State University
410 McGilvrey Hall
Kent OH  44242
phone: (330)-672-2017
e-mail: [log in to unmask]







------- End of forwarded message -------
_____________________
Joan R. Zeeb-Roman
Map Library
Kent State University
410 McGilvrey Hall
Kent OH  44242
phone: (330)-672-2017
e-mail: [log in to unmask]