-------- 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]