Virginia Division of Mineral Resources
c/o Department of Geology
College of William and Mary
PO Box 8795
Williamsburg, VA 23187
Telephone: (757) 221-2448x
Fax: 757) 221-2093
Geological surveys have begun to produce maps using geographic information systems (GIS) in response to the recent growth in the use of this technology by decision-makers and users in general. In the past, printed reports and maps conveyed geologic information. Now, a survey organization can deliver the same geologic information several ways: as a printed report and map, digital image files, and GIS data files.
Authorship and citation of paper products in literature follow long-standing and well-established conventions, but we have not found any acceptable or established convention for digital publications. This paper reviews several digital products, considers the relationship of authors to their work, and proposes authorship and citation guidelines for these new digital products.
The issue is further complicated because the term "digital" map has been applied to a product derived from any of three different procedures. A "digital geologic map" may refer to a simple copy created by scanning an original paper map and producing a raster image. Second, a scanned map image file may be enhanced using computer-graphics software (Adobe, Corel, etc.) to improve colors and linework, to add text, or to alter the explanation (legend). Third, a publication-quality "digital" geologic map may be assembled by capturing the map data in the numerous spatial data (vector) files of a GIS system followed by manipulation of these files to produce a map image. Here, the "intermediate" product (vector files) are also a desired end product.
With each of these three different procedures, there is a correspondingly different level of effort and technical competence required by the creator of the digital product. First, scanning a map and creating a raster image file requires no scientific or technical understanding of the geologic product. Second, enhancing the raster image of the scanned map with computer software and creating a raster image with standardized lines, text and graphic symbols is analogous to scribing and creating peel coats. Again, no scientific knowledge of geology is required to produce the raster map image from an original map, although the replication process requires skilled labor. The result of the first two processes is only an image whether raster or printed.
In the third procedure, GIS conversion requires several steps including invention of a data structure, design and entry of multiple attributes, attention to spatial accuracy, and mathematical conversion of spatial data from one map projection and scale to others. Location error for all points in the GIS files is established by initial georeferencing the scanned map and by computer entry of each point, typically achieved by the digitizer. For GIS conversion of previously published maps, there will always be some horizontal error in the vector data because it becomes separated from its original "married" topographic base. We have found geologic features are most accurately located relative to the original base only. Accurate entry of attribute data into the GIS files requires an interpretation of geologic map data. There are also digital cartographic decisions in the final production of a map image from the GIS (vector) data. The GIS software is used to create tables of alphanumeric spatial data and a final raster map image. Digital conversion of maps into and by a GIS program creates the potential for errors in the GIS table data. These errors in the GIS data files are not obvious by visual examination of the image created from those GIS data files. The errors in the GIS data files are more difficult to expose and repair than errors created through scanning and use of computer graphics software. The result of the third process, (GIS conversion) is an image, raster or printed, and a number of files of alphanumeric GIS data.
Perhaps the relationship of the GIS files to the desired end products obscures authorship issues. Some organizations are interested in creating spatial data files from an existing map and the files are the only end products. Other organizations create GIS files and then use the files to create a final map (raster image and print). If the files are published, both the files and the map are end products; if the files are not published, they are an intermediate product. Furthermore, the GIS files might be compared to the scribed films and stick-up acetates (intermediate products) of the traditional map-making procedure. If the films and acetates could have been "published", who would have been their author? Responsibility for collection of the geologic data, synthesis of the data, creation of spatial data, and assembly of the map should be attributed accurately and consistently for all map products, regardless of the format. This requires clearly stating who is responsible for what.
1. One who replicates (copies) original work with software and creates only a graphic image does not require the same degree of experience or understanding of geologic science as the original author. Replication contrasts to compilation. Compilation is the creation of a new, modified (from others), different work (map) requiring intellectual effort, experience and understanding of geology. We should maintain this traditional definition and use of "Compilation". There is some confusion created because others have used "Compilation" in new titles or authorship of "digitally converted" older material and may have not made the distinctions here described.
2. The digital files (spatial data) created from any source map are different from the original map material (the image). The author of the digital files could have made errors or omissions. Responsibility and culpability for accuracy of the digital files cannot and should not be assigned solely to the original source author unless the source author created the digital files.
3. Reference to the original geologic map and author should remain intact in any subsequent reworking or adaptation.
4. Realize that every created work has a primary author. Referencing and citing printed material follows an established convention. Referencing and citing digital files and images has no established convention.
2. If the map merely is scanned and an image format or formats made, retain the authorship of the original source on the published electronic media. The title of the work should be "Scanned geologic map of the...", explicitly excluding the word "Digital"; the original mylar or compilation map could be assigned a "Manuscript Map XX" number or, if published, the formal map series number. In the example below, John Doe was the geologist who mapped Walkers quadrangle:
Doe, John, 1997, Scan of the geologic map of the Walkers quadrangle, Virginia: Virginia Division of Mineral Resources Manuscript Map 97-3 (unedited), [CD-ROM; 1997, July 5].
3. When GIS software is used to produce a map image and that image is published (raster or paper), primary authorship remains with the source author (originator). The title of a GIS-created paper map should read "Digital Geologic Map of.... Use of the word "digital" in the title clearly indicates GIS data was used and available. Furthermore, a clear distinction should be made between the new GIS-created image and a previously published map. Under the title on the digital map (image), list "Geology by John Doe" which gives full credit to the original author for the original work and the map image, printed or raster. Under the author and in smaller font, list something like "Digital Conversion (and/or digital editing) by Jane Smith" where Jane was the creator of the digital files (GIS files). Because the map is not merely a scan of the original, the relator term "adapted from" is used in the citation:
Doe, J., 1998, Digital geologic map of the Walkers quadrangle, Virginia: Virginia Division of Mineral Resources Digital Publication DP-5-A [CD-ROM; 1998, June 21]. Adapted from John Doe, 1997, Scan of the geologic map of the Walkers quadrangle, Virginia: Virginia Division of Mineral Resources Manuscript Map 97-3 (unedited), [CD-ROM; 1997, July 5].
If the map had not previously been open-filed or conventionally printed, the citation (Rader and Gathright are the geologic authors) might simply read:
Rader, E.K., and Gathright, T.M., II, 1998, Digital geologic map of the Front Royal 30 x 60 minute quadrangle, Virginia: Virginia Division of Mineral Resources Map on Demand MOD-12 [1998, September 11].
4. The raster images and paper geologic maps created from GIS spatial data require a different intellectual contribution than that required by computer graphics alone. If the GIS files (tabular data) are published, cite this data separately from the map image by assigning a distinctive title (Digital Publication DP-5-B) and appropriate authorship, but link the GIS data to the map image (Digital Publication DP-5-A). In addition, relate the GIS data to the source map by using "Adapted from..." in citations. As in the following example, the creator of the vector data is Jane Smith:
Smith, Jane, 1998, Geologic spatial data of the Walkers quadrangle, Virginia: Virginia Division of Mineral Resources Digital Publication DP-5-B [CD-ROM; 1998, June 21]. Adapted from John Doe, 1997, Scan of the geologic map of the Walkers quadrangle, Virginia: Virginia Division of Mineral Resources Manuscript Map 97-3.
5. When the original map author is also the creator of the GIS files and the original map has been published, the citation could appear as in #6, below, or as:
Whitlock, W., 1998, Digital geologic map of the Gate City quadrangle, Virginia: Virginia Division of Mineral Resources Digital Publication DP-10-A [CD-ROM; 1998, August 10]. Adapted from W. Whitlock, 1997, Geologic map of the Gate City quadrangle, Virginia: Virginia Division of Mineral Resources Open-File Map 97-12.
There would be a companion publication for the GIS vector data, cited as follows:
Whitlock, W., 1998, Geologic spatial data of the Gate City quadrangle, Virginia: Virginia Division of Mineral Resources Digital Publication DP-10-B [CD-ROM; 1998, August 10]. Adapted from W. Whitlock, 1997, Geologic map of the Gate City quadrangle, Virginia: Virginia Division of Mineral Resources Open-File Map 97-12.
6. When the mapping geologists compile their own field data on a computer with the GIS software (using the DRG topographic maps for a base), there is no mylar or intermediate product to open-file, unless it is the field notes. Several of our staff in Virginia are currently creating a final map and GIS vector files directly from field data. There could be one or two publications (titles) by the mapping geologist(s):
Berquist, C.R., Jr., 1999, Digital geologic map and geologic spatial data of the Williamsburg 30 X 60-Minute quadrangle, Virginia: Virginia Division of Mineral Resources Digital Publication DP-25 [CD-ROM; 1999, November 21].
7. Shared authorship and the order of authors would follow normal standards of mutual agreement between those involved with creation of the particular work. This includes consideration of the level of effort of digital compilers and digital editors for authorship of the digital files. Deceased geologic authors will gain a posthumous publication for their geologic map (image) if this convention is adopted.
8. This proposed citation style is somewhat new, and users of map products should be fully informed of this convention for authorship and citation. For example, to insure better understanding, put the following text on the raster (and subsequently printed) map image as well as on the CD-ROM jewel case:
Nolde, J. E., Henderson, Jr., and Miller, R. L., 1998, Digital geologic map of the Virginia portion of the Appalachia quadrangle: Virginia Division of Mineral Resources Digital Publication DP-7-A [CD-ROM; 1998, August 26]. Adapted from Nolde, J. E., Henderson, Jr., and Miller, R. L., 1988, Geology of the Virginia portion of the Appalachia and Benham quadrangles: Virginia Division of Mineral Resources Publication 72.
Digital Publication 7B is the digital dataset. Geologic information, concepts, and other products gained from the use of its files should be credited as follows:
Uschner, N. E., Jones, K. B., Sheres, D. E., and Giorgis, S. D., 1998, Geologic spatial data of the Virginia portion of the Appalachia quadrangle: Virginia Division of Mineral Resources Digital Publication DP-7-B [CD-ROM; 1998, August 26]. Adapted from Nolde, J. E., Henderson, Jr., and Miller, R. L., 1988, Geology of the Virginia portion of the Appalachia and Benham quadrangles: Virginia Division of Mineral Resources Publication 72.
Rader, E. K and Gathright, T. M., II, 1998, Digital geologic map of the Front Royal 30 x 60 minute quadrangle, Virginia: Virginia Division of Mineral Resources Map
On Demand MOD-9 [1998, September 11]. Adapted from Rader, E. K. and Gathright, T. M., II, 1998, Scan of the geologic map of the Front Royal 30 x 60 minute quadrangle, Virginia: Virginia Division of Mineral Resources Open-File Map 98-1 (unedited).
Berquist, C.R., Jr., Uschner, N.E., and Ambroziak, R. A., 2000, Spatial data of the digital geologic map of Virginia: Virginia Division of Mineral Resources Digital Publication DP-14-B [CD-ROM; 1999, May 5; revised 2000, July 5]. Adapted from Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.
In summary, these suggestions rely on accepting the notion that a geologic map image is different from GIS spatial data, and that each work may receive a separate title. Relating new and original work by using a phrase "adapted from..." or "modified from..." will help insure complete and accurate citations. Reference to original work may require geological surveys to assign preliminary materials (drafted geology on topographic mylars, manuscript paper maps) to a series such as "Open-File Map" or "Manuscript Map".
Three online sources of information were also helpful:
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This site is https://pubs.usgs.gov/openfile/of99-386/berquist.html