179 Mapping the Literature of GIS Edith A. Scarletto Edith A. Scarletto is Assistant Professor, Head Map Library, and Subject Librarian for Geography and Geology in the University Library at Kent State University; e-mail: escarlet@kent.edu. © 2014 Edith A. Scarletto, Attribution-NonCommercial (http://creativecommons.org/licenses/by-nc/3.0/) CC BY-NC This study analyzed citations in four journals, Annals of the Association of American Geographers, Cartography and Geographic Information Science, International Journal of Geographical Information Science, and Cartographic Journal, using Bradford’s Law of Scattering to identify three influence zones indicating core and peripheral titles in the study areas of GIS. Journals were ranked resulting in twenty-three core journals and 187 secondary journals. Scores for relevant indexing/abstracting services are also given to describe access points and coverage. The results can assist librarians and collection managers to support research in their institutions where GIS is both used and studied. cademic librarians have tra- ditionally fit emerging dis- ciplines into their existing structure, and Geography and Map Librarians (among others) have integrated Geographic Information Sci- ence (GIS) into their duties as quickly as faculty and students have adopted them. The ARL (Association of Research Librar- ies) GIS Literacy Project began during the early 1990s to recognize the increasing interest in GIS, and several SPEC KITS have been issued about its support includ- ing Davie1 and Salem.2 Using a working definition from the Encyclopedia of GIS, GIS is “knowledge acquired through processing geographically referenced data. Geographic Information Services are… provisions of information gener- ated from geospatial data.”3 As GIS has evolved into a discipline of its own, the challenge of supporting this research area has become more acute. Practitioners and researchers at many ends of the technical and theoretical spectrum need literature to support research and to contribute additional knowledge to their discipline. Academic libraries support research by collecting and providing access to journal literature in their institutions. The chal- lenge of selecting journals is exacerbated as budgets shrink and is especially dif- ficult for a multidisciplinary research area like GIS. This article examines and creates a list of the GIS journals in three ranked zones of influence using Bradford’s Law of Scattering.4 Analyzing citations in four source journals, Annals of the Association of American Geographers, Cartography and Geographic Information Science, Interna- tional Journal of Geographical Information Science, and Cartographic Journal, the resulting three influence zones can as- sist librarians in identifying core and peripheral titles in the study areas of GIS. Comparing these results with other bib- liometric studies of GIS and geography journals cited in this paper, in addition to using Impact Factors and metrics, can crl12-389 180 College & Research Libraries March 2014 help librarians determine where funding should be spent to cover the most ground for GIS literature support. Literature Review The discipline of Geographic Informa- tion Science (GIS or GIScience) has its history in both technical and theoretical disciplines. The development includes geographic information systems, com- puter science, remote sensing, geography, and statistics, making it nearly impossible to isolate where GIS begins and ends. To- gether with the technical and theoretical aspects of acquiring geographically refer- enced data (remote sensing and others), tools and knowledge contribute to the growing research area. This is sometimes referred to as GIScience, a scholarly discipline that addresses fundamental issues surrounding the use of a variety of digital technolo- gies to handle geographic informa- tion, namely information about places, activities and phenomena on and near the surface of the Earth that is stored in maps or images. GIScience includes the existing tech- nologies and research areas.5 The interdisciplinarity of GIS has been documented by Robert Allen,6 who identified the topics in the following areas: Biology/Ecology, Urban/Regional Planning, Technology, Natural Resources, Hydrology, Geography, Library Science, Atmospheric Science, Education, Trans- portation, Archeology, Criminology, and Medicine. He found that these disciplines both use and write about GIS. Other interdisciplinary studies of geography have included Anne Buchanan and Jean- Pierre Herubel.7 Buchanan and Herubel used citation analysis to identify the interdisciplinary nature of Historical Ge- ography, finding that the subdisciplines draw deeply from the related subject area, historical geography from history, economic geography from economics. As GIS is also expected to draw from the subdisciplines noted by Allen and Buchanan and Herubel above, many of the subdisciplines are likely to be present in the results of this study. Geography and GIS have also been studied using citation analysis to examine the characteristics of literature use in the disciplines. William Robinson and Paul Poston8 used citation analysis to inves- tigate this idea, looking at how authors used literature and the nature of what they cited. They found that authors in different journals used different percentages of lit- erature formats depending on the journal in which they published. The proportion of books cited compared to periodicals and report literature differed between publications. They also found a similar difference in the age of the literature used and the country where it was published. Each journal in turn exhibited different au- thor characteristics. The proportional use of different source formats is one aspect of the literature that will be examined in the Results section of this study. Additional studies have used the core journal approach with bibliometrics and citation analysis in geography to rep- resent the discipline, identifying most cited authors, classic authors over time, and the network of geography journals. These studies attempt to find the most influential or “classic” authors of the field. They include: Andrew Bodman;9 J.W. Whitehand;10 Neil Wrigley and Stephen Matthews;11 Robinson and Poston;12 and David Lee and Arthur Evans.13 Because the choice of source journals was a critical issue in the development of this study, a review of their methodologies follows. Bodman used the journals in the geography category listed in the Social Science Citation Index to generate his core journal list. He suggests that using a core journal list in affiliated disciplines could contribute to the breadth of the geography core for future studies.14 Wrigley and Mat- thews15 examined the geography journals Area, Transactions of the Institute of British Geographers, Annals of the American As- sociation of Geographers (AAAG), and Pro- Mapping the Literature of GIS 181 fessional Geographer for the articles cited most often in a ten-year period. Their list of most cited articles features four of the articles they deem as potential classics in geography. These classics were found in the journals Transactions of the Institute of the British Geographers, Progress in Human Geography, Geographical Analysis, and Environment and Planning A. Wrigley and Matthews are looking specifically at the field of geography. Robinson and Poston also looked at literature use, implementing what they considered to be “leading periodicals,” studying the titles AAAG, Applied Ge- ography, CJ, Economic Geography, and Geographical Analysis.16 Sampling these titles and examining citation patterns, they found that the authors in each of these journals differed in how they used geographic literature. Gatrell and Smith17 looked at journal citation networks using a set of twenty-two journals in geography to determine how journals were repre- sented in the citations of others on the list. They specifically excluded cartogra- phy journals making their resulting core list of literature less applicable to GIS, a cartographic tool. The journals AAAG, Antipode, Environment and Planning A, Geoforum, Geographical Analysis, Profes- sional Geographer, and Transactions of the Institute of British Geographer18 were high on their list in the citation networks. These articles present several meth- odologies for examining citations to illustrate user behavior with different perspectives, all with the idea that choos- ing core journals in an area of study can help to define the literature through the window of the study sample. Some could argue that GIS has moved beyond geography, making this background not as relevant. Often, the reputation of journals builds over time, and many titles have merged, split, or changed the focus of their publication to meet the changing direction of the discipline. As experienced in the course of this study, they both move away from traditional geography and move with it to include GIS. Studies have also been done looking at perceptions of quality and the impact status of journals in geography and GIS. Caron et al. (2008) comes closest to the purpose of this study by using a com- bination of subjective journal ranking (Delphi method) and objective Impact Factor analysis19 to determine an overall journal ranking in the field of GIS, using an international focus. The final ranking of GIScience journals20 by Caron et al. included forty-six titles. Their list contains a majority of international titles, including quite a few from remote sensing. Methodology The “Protocol for Mapping the Lit- erature for Nursing and Allied Health Professions”21 was followed as a model for this study. This protocol has been used primarily in the nursing and allied health professions22 and has been a well- respected methodology of the Medical Library Association for eighteen years. The protocol consists of choosing several source journals in a field and examining the citations to articles in those journals over a period of time to determine the most cited journals, or core literature. These journals are ranked into three zones of influence by the number of times they are cited by the articles included in the study: Zone 1, highest influence journals; Zone 2, moderate influence journals; Zone 3, lesser influence journals. GIS is a synthesis and applied methodology for remote sensing, surveying, mapping (cartography), computer engineering, statistical analysis, and (of course) geog- raphy. This makes it similar to the nursing and allied health fields, which are also based on several “sister” disciplines that contribute to and share resources. These similarities in how the fields relate to one another presented a unique application of the “protocol” to GIS literature. Selecting Source Journals The methodology of this study can be divided into the selection of source jour- nals, data collection, and Bradford’s Law. 182 College & Research Libraries March 2014 The first step in “mapping the literature of GIS” was the selection of source jour- nals. Source journals are the journals from which the articles and subsequent citations listed in those articles are stud- ied. All of the citation data collected was drawn from articles published in the source journals during the time of analy- sis (2008–2010). This is arguably the most important step in the analysis process and subject to the most debate. When trying to determine the core literature of the discipline based on ranking, which source journals are chosen for analysis can create a source of bias in the results. Several criteria were applied to the selection of source journals for this study. Using English language titles, the first criterion was the association with a pro- fessional organization, the second was the presence of a Thompson Reuters Journal Impact Factor from the Journal Citation Reports, the third was focus on the topic of Geographic Information Science, and the fourth was broad circulation. While professional associations are not the only source of scholarly journals, they do indi- cate a level of responsibility to the profes- sion. All four source journals had some affiliation with a professional association. Also, three of the four journals selected are listed in the Thompson Reuters Journal Citation Reports (JCR), which calculates the Journal Impact Factor. Cartography and Geographic Information Science (CGIS) was the exception. Impact Factors are defined as the “average number of times articles from the journal published in the past two years have been cited in the JCR year.”23 Many studies have noted the flaws of the Journal Impact Factor;24 however, it is a recognizable and repeatable metric. A broad circulation provides evidence of interest in the publication and the oppor- tunity for professionals to be exposed to its content. The professional affiliations, publishers, and one-year/five-year Impact Factor and Journal Citation Reports half-life for each source journal are listed in table 1. As CGIS is not indexed in the Journal Citation Reports and does not have an Impact Factor, the metrics from Scopus, SJR for prestige, and SNIP for normalized impact are also listed.25 Starting with the Magazines for Libraries (2010) list of journals in “Cartography, TABLE 1 Source Journal Details Journal Professional Association Publisher Impact Factor (2010) 1yr/5yra Scopus Metrics (2010) SJR/ SNIPb Half Life (2010) AAAG Association of American Geographers Routledge 1.889/2.986 .045/1.985 >10.0 IJGIS Association of American Geographers/ Royal Geographical Society Taylor & Francis 1.489/2.162 .061/2.854 8.9 CGIS Cartography & Geographic Information Society American Congress on Surveying and Mapping .036/1.056 CJ British Cartographic Society Maney Publishing 0.607/0.644 .032/.822 7.7 a. Institute for Scientific Information, Journal Citation Reports, 2010. b. Elsevier Science Publishers, Scopus. Mapping the Literature of GIS 183 GIS and Imagery,”26 the Annals of the As- sociation of American Geographers (AAAG), International Journal of Geographical Infor- mation Science (IJGIS), Cartography and Geographic Information Science (CGIS), and Cartographic Journal (CJ) were chosen based on the above criteria. Exclusions in the choice of source journals were inevi- table in the scope of the present analysis. While both remote sensing and engineer- ing of GIS systems are critical to the GIS endeavor, journals focused primarily on those topics were excluded for this analysis. Two titles that were considered and then excluded were Cartographica and Transactions in GIS. Transactions in GIS was excluded because it lacked a profes- sional association affiliation and Journal Impact Factor at the time of analysis, while Cartographica was excluded because of its very small circulation (433 accord- ing to Magazines for Libraries)27 and a lack of Journal Impact Factor. In the Results section, both of these journals are repre- sented as influence Zone 1, indicating that their exclusion as source journals did not adversely affect their standing, though it may have affected the position within the zone rankings. Data Collection Using the source journals, the sample comprised all articles published in a three-year period (2008 through 2010) excluding editorials and book reviews. The references for the study articles were downloaded from the Thompson Reuters Science Citation Index, Social Sciences Cita- tion Index, and Elsevier Scopus and then entered into a Microsoft Excel spread- sheet for the first stage of analysis. Each entry contained the source journal title, source article title, source article author, and source article publication year. Each cited reference was then associated with a source article, cited author, title, volume, issue, and year of publication where ap- propriate. The published reference list of each source article was used to verify each of the citations listed in the resulting database. Format types were assigned to each citation according to its publication type in the electronic version of Ulrich’s Periodi- cals Directory:28 journal (scholarly journal), book (monograph), proceeding, and other (including Internet sources, software programs, government documents, unknown). Ulrich’s Periodical Directory was chosen as a valid, repeatable, and independent determiner for assigning the format of “journal” or “book” to a title and to verify journal title changes. All previous titles were listed under the cur- rent title when possible. Some exceptions are noted in the Discussion section of the study. The resulting information was tabulated in a Microsoft Access database so that queries by format type, source journal, and publication date could be analyzed. The dataset was examined to determine how many citations of each for- mat were found for each source journal. Percentages were calculated to illustrate how much of the citation activity was at- tributed to journals, as journals were the primary focus of the study. Bradford’s Law Bradford’s Law of Scattering was then ap- plied to the resulting data from the source journals. Bradford’s Law states that, when you divide the total number of citations in a list of literature by three, the top third of the accumulated citations constitute the most influential journals in the field; the second group constitutes the broader influence in the field. This influence drops considerably with the third grouping of citations, which made up the major- ity of the database. 29 For this study, the total number of citations (n=12,081) was divided into thirds. Then, journals were listed in descending order by total number of citations. Using a cumulative count of the number of citations, when the number of citations reached one third of the total, the cluster for Zone 1 was drawn. When the count was made with the remaining journals and again reached one third of the total, this cluster was labeled Zone 2. The remainder of the list was clustered into 184 College & Research Libraries March 2014 Zone 3. When Zone 1 was divided from Zone 2, the difference in the numbers of citations on each side of the zone was very distinctive. Zone 1 contained journals with a minimum of seventy-seven citations and Zone 2 a maximum of sixty-eight citations. However, the division between Zone 2 and Zone 3 was less distinct. The Zone 3 grouping occurred in the middle of the list of journals all with nine citations. The journals having been listed alphabetically within their citation counts, all journals cited nine or fewer times were reassigned to Zone 3. The journals in Zones 1 and 2 were examined for indexing coverage using the bibliographic databases Social Sciences Citation Index (SSCI), Science Citation Index Expanded (SCIE), GEOBASE, GeoRef, and Scopus. Scopus is a citation indexing tool similar to Science and Social Science Cita- tion Index is a multidisciplinary indexing source. GEOBASE was chosen for its concentration on Geographic literature and GeoRef as a complement to physical geography coverage. Using the protocol method provided by Delwiche, Schloman, and Allen,30 each journal was searched in the indexing source to identify the total number of entries for the three years of the study. The largest number of entries for each title was determined to be the 100 percent coverage level and assigned a score of five. The remainders were compared against it using the percentage method and assigned a coverage score based on the point system below: 5 point= 95–100% coverage 4 points= 75–94% coverage 3 points= 50–74% coverage 2 points= 25–49% coverage 1 point= 1–24% coverage 0 point= <1% coverage (Delwiche, Schloman, and Allen, Map- ping the Literature of Allied Health: Project Protocol, 21)31 Results A total of 12,081 citations in 486 articles were published during the study period 2008–2010. The results of the format as- signments for citations in each of the source journals are listed in table 2. The data give an indication of the level of citation activity in the source journals for each format type. It also shows the variety of citations per journal and the variety of citation activity (number of citations) per journal. The citations were also divided based on year of publication to examine the currency of each citation format. The Annals of the Association of American Geog- raphers (AAAG) and International Journal of Geographical Information Science (IJGIS) by far contributed the most journal articles to this dataset, AAAG being the largest contributor at 5,987 journal articles and IJGIS contributing 4,390. Together they represent more than double the num- ber of journal articles in either of the remaining journals. These two journals also contributed the largest number of citations to the overall database by more than half. The average number of citations TABLE 2 Format Types by Source Journal and Citation Frequency Number of Citations in Source Journals Cited Format Type AAAG IJGIS CGISC CJ Totals No. % No. % No. % No. % No. % Journal Articles 5,987 47.2% 4,390 52.3% 1,191 50.9% 513 31.6% 12,081 48.2% Books 4,246 33.4% 1,870 22.3% 510 21.8% 627 38.7% 7,253 28.9% Other 2,346 18.5% 1,312 15.6% 468 20.0% 361 22.3% 4,487 17.9% Proceedings 118 0.9% 827 9.8% 170 7.3% 121 7.5% 1,236 4.9% Total 12,697 100.0% 8,399 100.0% 2,339 100.0% 1,622 100.0% 25,057 100.0% Mapping the Literature of GIS 185 per article differs by journal, showing that AAAG had an average of thirty-six citations per article (n=163 articles), while IJGIS had an average of twenty citations per article (n=213 articles). Cartography and Geographic Information Science (CAGIS) had nineteen citations per article (n=62 ar- ticles), and Cartographic Journal (CJ) had an average of ten citations per article (n=48 articles). Overall, the average number of citations per article was twenty-four. Except in CJ, journal articles comprised nearly half of the citations in the source ar- ticles. Journal articles comprised one third of the citations in CJ, with another third composed of books. Books constituted 28 percent of the total citations compared to the 48 percent for journal articles and 17 and 4 percent for other and proceed- ings formats respectively. Making up a third of the citations, books constituted a significant part of the cited literature in the study and are indicating a significant component in GIS research. Conference proceedings were also a significant portion. Many conferences could have been examined on their own for levels of influence in the profession as several of them made multiple appearances (such as AutoCarto). The age of citations is always a topic of discussion in citation analysis, especially regarding the half-life32 of book, journal use, and impact.33 As seen in table 3, over 50 percent of the journal articles in the dataset were published between 2001 and 2011, 30 percent from 1991 to 2000, and the remainder distributed through the remaining years examined. For books, 40 percent of the citations were from 2001 to 2011 and a third from 1991 to 2000. Current literature from both books and journals are the primary citations for the studied literature. The remain- ing formats, “other” and “proceedings,” exhibited over 50 percent representation in 2001–2011. Conferences are often a source of new developments in the field, especially with applied tools such as GIS. Websites and trade journals may also be more impactful in recent years detailing newer procedures and activity. Overall, the most recent two decades comprise more than 90 percent of the total citations. This lends to support the half-life theory of currency as a large measure of useful- ness for the studied literature. GIS is also a relatively new discipline, and this fact has no doubt contributed to the currency represented in the citations. The division of journals into three influence zones based on Bradford’s Law of Scattering is displayed in table 4. Zone 1 contains twenty-three journals, or 1 percent of the cited journals. The second Zone comprises only 10 percent of the cited journals and 190 moderate influ- ence journals. The last influence zone, TABLE 3 Cited Format Types by Publication Year Periods Publication Year (Range) Cited Format Type Journal Articles Books Other Proceedings Total No. % No. % No. % No. % 2001–2010* 6,644 55.0% 2,896 39.9% 2,876 64.1% 747 60.4% 13,163 1991–2000 3,734 30.9% 2,579 35.6% 962 21.4% 362 29.3% 7,637 1981–1990 886 7.3% 911 12.6% 228 5.1% 90 7.3% 2,115 1971–1980 420 3.5% 424 5.8% 116 2.6% 12 1.0% 972 pre-1971 397 3.3% 443 6.1% 239 5.3% 25 2.0% 1,104 unknown 0 0.0% 0 0.0% 66 1.5% 0 0.0% 66 12,081 100.0% 7,253 100.0% 4,487 100.0% 1,236 100.0% 25,057 186 College & Research Libraries March 2014 Zone 3, contained 1,857 cited journals. These comprised 89 percent of the cited journals. These results are consistent with the numbers for other core literature studies using this protocol34 where similar percentages of journals make up the three influence zones. Of the journals in Zone 1, fifteen titles were found with more than 100 citations. These include major titles in geography, remote sensing, computer systems and GIS, cartography, The journals in Zone 1 and Zone 2 are listed in table 5 with their relevant indexing coverage. Indexing coverage was determined using Delwiche, Schlo- man and Allen’s methodology.35 Scopus, GEOBASE, Science Citation Index Expanded (SCIE), and Social Science Citation Index (SSCI) provided the most complete cov- erage of the source journals, with both high average and cumulative indexing scores. This is not surprising, since Scopus and the SSCI/SCIE seek to provide broad subject as well as scholarly coverage. These provide the bulk of the indexing coverage for Zone 1 titles. Surprisingly, GeoRef provided less indexing coverage than was expected based on the perceived applied uses for GIS in earth sciences. It may be that the methodology (number of citations in the index based on the study timeline) did not indicate as much use as was expected. GEOBASE provided good indexing coverage in Zone 1 titles on par with SSCI/SCIE and Scopus. Zone 2 titles had less indexing coverage overall, but especially from GEOBASE, perhaps due to the interdisciplinarity of the titles from outside the geography scope. Scopus maintained coverage throughout the listing and seems to cover with more consistency even than SSCI/SCIE. Discussion Many of the core journals listed in Zone 1 of this study have also appeared in other core journal lists providing validation for the first zone of influence. Four of these, Transactions of the Institute of British Geographers, Progress in Human Geography, Geographical Analysis, and Environment and Planning A, were noted as contain- ing “classics in geography” by Wrigley and Matthews.36 Robinson and Poston37 also identified important titles: AAAG, Applied Geography, Cartographic Journal, Economic Geography, and Geographical Analysis, which appear in Zone 1, except for Economic Geography, which is near the top of Zone 2. From Gattrell and Smith, seven of their selections appear in Zone 1, including: AAAG, Antipode, Environment and Planning A, Geoforum, Geographical Analysis, Professional Geographer, and Transactions of the Institute of British Ge- ographers. In the final ranking of GIScience jour- nals by Caron et al.,38 sixteen titles are listed in Zone 1 and eleven of the journals are listed in Zone 2. His final rankings con- tain more international titles and remote sensing titles than this study. This study specifically excluded remote sensing titles as source journals in favor of the more TABLE 4 Distribution by Influence Zone of Cited Journals and References Cited Journals Cited Journal References Zone No. % No. % Cumulative Total 1 23 1.1% 4,027 33.3% 4,027 2 190 9.1% 4,028 33.3% 8,030 3 1,857 89.7% 4,051 33.5% 12,081 Total 2,070 99.9%a 12,106 100.0% a. Totals may not add to 100 due to rounding. Mapping the Literature of GIS 187 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 International Journal of Geographical Information Science 838 4 0 4 5 5 Annals of the Association of American Geographers 458 3 0 3 0 5 Cartography and Geographic Information Science 262 4 0 5 0 4 Environment and Planning A 216 4 0 4 0 5 Computers Environment and Urban Systems 162 4 0 5 0 5 Photogrammetric Engineering and Remote Sensing 162 4 0 4 5 1 Geographical Analysis 161 4 1 4 0 5 Cartographica 144 4 0 5 0 1 Transactions in GIS 141 4 0 5 0 3 Progress in Human Geography 139 2 0 2 0 5 Professional Geographer 136 2 1 2 5 0 Science 129 3 0 4 5 1 Environment and Planning B 126 3 0 3 0 5 Computers and Geosciences 113 5 0 5 0 0 Political Geography 112 3 0 4 0 5 Environment and Planning D 101 3 0 4 0 1 International Journal of Remote Sensing 97 4 1 5 5 1 Cartographic Journal 94 3 0 4 0 5 Geoinformatica 87 4 0 5 5 1 Institute of the British Geographers Transactions 86 4 0 5 0 5 Nature 81 3 1 4 1 5 188 College & Research Libraries March 2014 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 Antipode 80 4 0 4 0 5 Geoforum 77 4 0 5 0 5 Total Indexing Coverage for Zone 1 83 1 95 31 80 Average Score 3.6 0.04 4.1 1.3 3.4 ZONE 2 Water Resources Research 68 4 3 4 5 0 Journal of Geographical Systems 66 4 0 5 0 4 Journal of Hydrology 66 4 4 5 5 0 Ecological Modeling 65 0 5 5 1 4 Economic Geography 65 0 3 0 5 3 Remote Sensing of Environment 63 5 1 5 5 1 Geomorphology 61 5 4 5 5 0 World Development 60 5 0 5 5 0 Geographical Review 59 3 0 3 0 5 Landscape Ecology 58 5 0 5 5 1 Urban Studies 57 3 0 3 0 5 Journal of Climate 56 4 1 5 5 0 IEEE Transactions on Visualization and Computer Graphics 52 0 0 5 5 1 URISA Journal 51 0 0 5 0 0 Urban Geography 50 3 0 4 0 5 Climatic Change 46 2 1 5 5 1 Landscape and Urban Planning 46 4 0 5 5 5 Hydrological Processes 45 4 3 5 5 0 Conservation Biology 41 4 0 5 5 1 Geoderma 40 5 4 5 5 0 Statistics in Medicine 39 0 0 5 5 1 Mapping the Literature of GIS 189 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 International Journal of Health Geographics 37 4 0 5 0 5 Social Science and Medicine 36 4 0 5 0 0 Area 35 3 0 3 0 5 Global Environmental Change 35 4 0 5 5 5 Agriculture Ecosystems and Environment 34 5 0 5 5 1 Human Ecology 34 3 0 4 0 5 Papers in Regional Science 34 3 0 3 0 5 Monthly Weather Review 31 4 0 5 2 5 Social & Cultural Geography 31 3 0 3 0 1 American Planning Association Journal 30 2 2 0 5 5 American Statistical Association Journal 30 0 0 5 5 1 Ecology 30 4 0 5 5 1 Geopolitics 30 4 0 4 0 5 International Journal of Urban and Regional Research 30 3 0 3 0 5 Geographical Journal 29 5 2 2 0 5 Information Visualization 28 0 2 0 5 2 Biosciences 26 0 4 5 1 0 Geografiska Annaler B 26 0 0 0 0 0 Geojournal 26 0 3 5 5 3 Geophysical Research Letters 26 0 5 0 0 3 ISPRS Journal of Photogrammetry and Remote Sensing 26 2 5 5 0 4 Society and Natural Resources 26 0 0 5 0 4 190 College & Research Libraries March 2014 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 Environmental Management 25 0 4 5 5 4 Geological Society of America Bulletin 25 0 5 4 2 0 International Journal of Human Computer Studies 25 0 5 5 0 4 Journal of Biogeography 25 4 0 5 5 0 Mathematical Geosciences 25 4 1 3 5 0 Parallel Computing 25 0 0 2 5 1 Quaternary Research 25 5 5 5 5 1 Ecological Applications 24 4 0 5 5 1 Emerging Infectious Diseases 24 0 0 5 5 0 IEEE Transactions on Pattern Analysis and Machine Intelligence 24 0 0 5 5 1 International Journal of Climatology 24 5 1 5 5 0 Progress in Physical Geography 24 4 5 5 5 0 Earth Surface Processes and Landforms 23 4 0 5 0 0 Environmental Modeling and Software 23 4 0 5 5 0 Cartographic Perspectives 22 4 0 5 0 0 Ecological Economics 22 0 3 0 5 4 IEEE Transactions on Geoscience and Remote Sensing 22 3 1 5 5 0 Journal of Geography 22 3 0 3 0 5 Soil Science Society of America Journal 22 5 1 5 5 0 American Journal of Public Health 21 0 0 5 5 5 Mapping the Literature of GIS 191 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 American Meteorological Society Bulletin 21 0 1 3 5 1 Computers & Operations Research 21 0 0 5 5 1 European Journal of Operational Research 21 0 0 5 5 2 Journal of Applied Meteorology and Climatology 21 4 0 4 5 0 Journal of Environmental Management 21 4 0 5 5 1 Journal of Geophysical Research 20 3 2 4 5 1 Spatial Cognition and Computation 20 0 0 2 0 5 American Economic Review 19 0 0 5 0 4 Cultural Geographies 19 2 0 2 0 5 Gender Place and Culture 19 3 0 3 0 5 Graphical Models 19 4 0 5 5 0 IEEE Transactions on Knowledge and Data Engineering 19 0 0 5 5 1 Journal of Economic Geography 19 3 0 3 0 5 Regional Studies 19 4 0 4 0 5 American Journal of Sociology 18 0 0 1 0 5 American Sociological Review 18 5 0 5 0 5 Atmospheric Environment 18 5 0 5 5 0 Biological Conservation 18 5 0 5 5 0 Canadian Geographer 18 3 0 3 0 5 Journal of Historical Geography 18 2 0 2 0 5 192 College & Research Libraries March 2014 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 ACME: An International E-Journal for Critical Geographies 17 0 0 5 0 0 Ambio 17 4 1 5 4 1 American Journal of Epidemiology 17 2 0 2 5 1 Annual Review of Environment and Resources 17 0 1 5 5 5 Annual Review of Sociology 17 0 0 5 0 5 Artificial Intelligence 17 0 0 5 5 1 Concurrency and Computation Practice and Experience 17 0 0 5 0 0 Geology 17 4 0 5 5 0 ACM Computing Surveys 16 0 0 5 5 0 Annals of Regional Science 16 3 0 5 0 3 Canadian Journal of Forest Research 16 5 0 5 5 1 Cognitive Science 16 0 0 4 0 5 Development and Change 16 2 0 2 0 5 Global Ecology and Biogeography 16 5 0 5 5 0 Information Sciences 16 0 0 5 5 1 International Journal of Applied Earth Observation and Geoinformation 16 4 0 4 5 1 Journal of Transport Geography 16 4 0 4 0 5 Royal Statistical Society Journal A 16 0 0 2 5 5 Social Forces 16 0 0 3 0 5 Tijdschrift voor Economische en Sociale Geografie 16 0 0 3 0 5 Mapping the Literature of GIS 193 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 Climate Research 15 4 0 4 5 1 Ecology and Society 15 4 0 5 5 3 Forest Ecology and Management 15 4 0 5 5 1 Fuzzy Sets and Systems 15 0 0 5 5 1 Health and Place 15 5 0 5 0 0 Journal of Coastal Research 15 2 1 2 5 1 Operations Research 15 0 0 5 5 4 AIDS Care 14 4 0 4 0 5 Applied Geography 14 0 0 5 0 5 Cognitive Psychology 14 5 0 5 0 5 Environmental Health Perspectives 14 0 0 5 5 5 Geografiska Annaler A 14 0 0 4 5 1 Geography Compass 14 4 4 5 5 1 IEEE Transactions on Systems Man and Cybernetics 14 5 0 5 0 0 Journal of Urban Affairs 13 0 0 5 5 1 ACM Transactions on Graphics 13 2 0 3 0 5 Biometrika 13 0 0 5 5 1 Catena 13 0 0 5 5 1 D Lib Magazine 13 3 5 5 5 1 Demography 13 0 0 5 0 0 Economic and Political Weekly 13 0 0 5 0 0 Eurasian Geography and Economics 13 5 0 4 0 5 Historical Geography 13 5 0 5 0 0 Journal of Visual Languages and Computing 13 0 0 5 5 1 194 College & Research Libraries March 2014 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 Management Science 13 0 0 4 5 5 Numerische Mathematik 13 0 0 5 5 0 Population, Space and Place 13 4 0 4 0 5 Sociologia Ruralis 13 4 0 5 0 5 Epidemiology 12 0 0 1 5 1 International Regional Science Review 12 5 0 5 0 5 Pattern Recognition 12 0 0 5 5 0 Risk Analysis 12 4 0 5 5 5 Social Science Quarterly 12 0 0 5 0 5 Surveying and Land Information Science 12 4 0 5 0 0 Theory Culture and Society 12 0 0 5 0 0 Third World Quarterly 12 5 0 5 0 5 Transportation 12 4 0 5 5 5 Transportation Research A 12 5 0 5 5 5 Accident Analysis and Prevention 11 0 0 5 0 5 Algorithmica 11 0 0 5 4 1 Annals of Mathematics and Artificial Intelligence 11 0 0 5 5 1 Biometrics 11 4 0 5 5 1 Computational Statistics & Data Analysis 11 0 0 5 5 0 Ecosystems 11 5 0 5 5 1 Environmental Conservation 11 4 0 5 5 1 Environmental Science and Policy 11 0 0 5 5 2 GIScience and Remote Sensing 11 5 5 5 0 0 Global Biogeochemical Cycles 11 4 2 4 5 0 Mapping the Literature of GIS 195 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 International Migration Review 11 2 0 2 0 5 Journal of Conflict Resolution 11 0 0 5 0 5 Journal of Geophysical Research Atmospheres* (Georef includes all parts) 11 4 5* 1 0 0 Journal of Peace Research 11 0 0 2 0 5 Journal of Soil & Water Conservation 11 4 0 5 5 1 Lancet 11 0 0 5 5 2 Psychological Review 11 0 0 5 5 5 Review of African Political Economy 11 4 0 5 0 5 Royal Statistical Society Journal B 11 0 0 4 5 1 Stochastic Environmental Research and Risk Assessment 11 5 1 5 5 1 Transportation Research B 11 4 0 5 5 5 Transportation Research C 11 4 0 5 4 2 Urban Affairs Review 11 3 0 3 0 5 Agricultural and Forest Meteorology 10 4 0 5 5 1 Annals of Operations Research 10 0 0 5 4 2 Annual Review of Anthropology 10 5 0 5 0 5 Boundary Layer Meteorology 10 5 0 5 5 0 British Medical Journal 10 0 0 0 5 1 Climate Dynamics 10 5 1 5 5 0 Computer Graphics Forum 10 0 0 5 5 0 Computer Journal 10 0 0 5 5 1 196 College & Research Libraries March 2014 TABLE 5 Distribution and Indexing of Coverage 2008–2010 of Cited Journals in Zones 1 and 2a Cited Journal # of Citations GEOBASE GeoRef Scopus Science Citation Index Expanded Social Science Citation IndexZONE 1 Computers and Graphics 10 0 0 5 5 1 Environment and Behavior 10 4 0 4 0 5 Estuarine Coastal and Shelf Science 10 5 0 5 5 0 Hydrology and Earth System Sciences 10 4 1 5 5 1 Journal of Political Economy 10 5 0 5 0 5 Journal of Rural Studies 10 3 0 4 0 5 Journal of Wildlife Management 10 4 0 5 5 1 Land Economics 10 4 0 5 0 5 Natural Hazards 10 4 1 5 5 1 Pattern Recognition Letters 10 0 0 5 5 0 Physical Geography 10 2 1 5 2 1 Population Research and Policy Review 10 4 0 5 0 5 Public Administration Review 10 0 0 3 0 5 Quarterly Journal of Engineering Geology and Hydrogeology 10 4 4 5 5 1 Quaternary Science Reviews 10 4 2 5 5 1 Technometrics 10 0 0 5 5 0 Transportation Research Record 10 0 0 5 5 2 Water International 10 0 1 5 5 1 Total Indexing Coverage for Zone 2 443 113 805 559 432 Average Score 2.33 0.59 4.23 2.94 2.27 a. Adapted from Burtis and Taylor, Mapping the Literature of Health Education: 2006-2008, 210. Mapping the Literature of GIS 197 general GIS titles, while remote sensing remained an important part of the Caron et al. listings. Caron et al. also focused on international coverage, while the study discussed here focused only on English language titles. Sixteen of the titles ranked by the Caron et al. study are not included in this study’s Zone 1 or Zone 2 rankings. These variations could be due to the meth- odologies employed. The Delphi method was a series of rankings based on perceived prestige and Journal Impact Factor rank- ings. Second, Journal Citation Reports does not index all of the journals listed in Zones 1 and 2. This would specifically exclude them from the Caron et al. rankings. Third, quite a few of the titles noted by Caron et al. are foreign language publications, which could limit their accessibility for North American and British researchers. The results of this citation analysis can be applied in academic libraries as noted in other core journal studies.39 They can be used as a core journal list by which to measure journal coverage of a discipline by a library. Determining a usable core list of GIS journals is a difficult endeavor and depends heavily on intended purpose of the final list. Several of the studies cited above corroborate the significance of jour- nals selected in Zone 1 to the field of GIS. These journals represent the most reliable finding of the study and can be used as a strong measure of core literature. Since the purpose of this research was to sup- port academic librarians and their efforts to provide collection and research sup- port, librarians can be fairly confident in using the core journal lists as a benchmark for their own collections. The journals in Zone 2 present a moderate influence in the field based on Bradford’s Law of Scattering and a corresponding moderate corroboration in other similar research. The journals in this secondary list provide a supplement to a GIS core journal collec- tion. A secondary journal list can be used to build the interdisciplinarity of a GIS journal collection at an institution. Core journal lists can also be used to measure the influence of journals where faculty have published and to identify influential journals where they could potentially publish. Paynter40 has noted that supporting faculty research using core lists and impact factors is an impor- tant role for librarians. Librarians can provide core journal lists with several metrics to faculty who are expected to publish so that they can indicate the value of their work. While Impact Factors are an important metric, GIS is an interdisciplin- ary field, and interdisciplinary lists may be more difficult to identify for faculty.41 The subject categories used by the Journal Citation Reports Impact Factors do not provide a category that cleanly represents GIS. Because it is so interdisciplinary, journals may fall into several categories that are more difficult to identify in the rankings. Librarians who work with fac- ulty who need to publish can point them to Zone 1 and Zone 2 journal listings as a metric for their publications and for publishing opportunities. A multitiered core journal list can be used to identify related disciplines and applied areas for GIS. Both traditional and related areas of geography are rep- resented in the study results including remote sensing, computer science, com- puter engineering, applied geography, physical and human geography, as well as related fields such as psychology. The titles in Zone 2 can help fill in less popular or lesser known titles and supplement a journal collection in GIS. This is often the most difficult part of collections as noted in Corby (2003).42 The Zone 2 titles trail off considerably from most to least cited. A variety of disciplines is repre- sented throughout Zone 2 and it seems to expand beyond Geography the further down the list it goes. Depending on the reach of GIS into other disciplines at a particular institution, librarians may use that variety to build the case for promo- tion of GIS into other disciplines as both a research area and as an applied tool. At my own institution, I have used such a list to work with the Heath Sciences librarian to locate a variety of journals related to 198 College & Research Libraries March 2014 health informatics and health geography publications. As the Public Health College on campus becomes more interested in GIS, their interest has reflected back to the GIS professionals on campus. While it was not originally one of the concentrations of the Geography department, they have also become more interested as a result of their colleagues on campus. Now these journals can support several groups of researchers with similar interests. Other GIS librarians might use this example to expand or market services to researchers, providing examples of applied research from the journals noted in those fields. The characteristics of the source jour- nals studied here can also be extrapo- lated to some extent to the researchers themselves. The authors in the journals studied tend to use literature (both book and journal literature) published in the last ten years, indicating a preference for recent information. Whether this is because GIS is technology based and researchers are closely watching new developments in their field, or just that technology moves so quickly that it begs discussion, is not clear. GIS researchers also use journal literature more than any other format, closely followed by books. Journals are clearly an important source for GIS researchers, and the collection development implications should be closely monitored. Librarians can use this information when making weeding issues or when deciding what materials should be kept in close reach on campus and which might be candidates for storage or off-campus relocations. Other decisions such as funding issues between serial and monographic collections can also be examined by looking at the characteristics of the literature the authors cite. These authors are continuing to use both books and journal articles rather evenly, while other disciplines may move in one direc- tion or the other. Using this information, librarians may be less likely to generalize GIS researchers with other disciplines who have changed this type of literature usage. Using the study results related to in- dexing, librarians can have a better idea of which databases are best at discover- ing the core journals in GIS. Traditional subject-based databases are not necessar- ily the only products covering the inter- disciplinarity of the field. GEOBASE is not the only strong indexer of this literature. Librarians should be aware of this when directing GIS-focused researchers. They would be wise to direct them to Scopus and the SSCI/SCIE for comprehensive literature coverage as well as traditional sources. Especially in the case of Zone 2 titles, the aggregate indexing sources Scopus and SSCI/SCIE are more useful to researchers. Undergraduate students, who are less likely to be familiar with peripheral databases, or those in subject areas other than their own, may not re- alize that GIS is covered in many other places. They would also benefit from the broad coverage of Scopus and SSCI/ SCIE for both technique and application resources in GIS. Careful citation analysis with both sampling and nonsampling method- ologies can bring into focus the literature used by scholars, providing librarians and researchers with insight into the informa- tion usage patterns in a discipline. While the information can be parsed into the many variables described above, it is the goal of this study to determine a ranked list of influential journals for the academic GIS discipline. These findings contribute to the body of knowledge that informs what literature is important to the grow- ing discipline and provides librarians with behavioral data about GIS research- ers and their literature needs. Limitations of Study There were several challenges to compil- ing the data for this study. Unknown citations, incomplete information in the citation databases used to download references, foreign language titles, theme journal issues, and the selection of core journals could possibly contribute to different results. While the Thompson Mapping the Literature of GIS 199 Reuters SSIE/SSCI are extensive databases of knowledge for analysis, the data pre- sented several challenges for this study. Many nonjournal citations were excluded from the data, and many citations were misattributed in both the author and title fields in the SSIE/SSCI. The published manuscript was used to verify a complete citation list for each article, but this also created some problems. The authors of the journal articles also misattributed sources in their bibliographies and refer- ence lists. If the information provided by the source author was not sufficient to verify a citation and assign it to a unique journal title, the citations were assigned an “other” format. Some foreign language titles were also difficult to locate in the Ulrich’s Periodical Directory using either the title or the ISBN number or because the author chose to use a romanized title. A translated or romanized title was not always the formal name of the non-English language journal. Journals with common titles were investigated to confirm that the assigned article was attributed to the correct journal, as many journals share similar titles. Again, if this was not verifiable, the title was assigned to the “other” format. A second data challenge was a theme issue in AAAG that examined the cover- age of core topics over the course of the journal’s history (Volume 100, Issue 5, 2010 Centennial Issue). These articles specifically examined other articles from the AAAG and traced all of the articles on a specific topic over the course of the journal’s publications. Consequently, these articles often cited over 100 articles in the review, increasing the self-citation of AAAG. Many journals compile theme issues throughout publication; while one theme issue in a three-year span might not skew the data, in this case, the sheer volume of self-citations was determined to be a significant variable in the analy- sis. Therefore, all statistics and counts were calculated without the theme issue data. While the source journals are well represented, any study of this type could find that self-citation could influence the results. Two of the journals excluded from this study were represented highly in Zone 1. These exclusions are a potential limitation; but their positions in the final ranking (Cartographica and Transactions occupy positions 8 and 9 respectively in the descending list of total citations) affirm their influential role in the disci- pline. In a follow-up study, Transactions would be included as a source journal as it was recently added to the Journal Citation Reports. Other limitations are the cited journals themselves. Many of them have changed titles and split titles over the course of publication. If possible, these were collated under the current title name. For others, where the reference was made to the previous title, which was split into more than one journal, determining the final journal attribution was difficult. In the case in which the current title could not be de- termined, the citation was listed under the older title. The result was that some journals are represented in the zone listings multiple times under different iterations of the title name (Journal of Geophysical Research; IEEE Transactions on Systems Man and Cybernetics are ex- amples). This does skew the zone listing, but attributing the citations to newer titles that may or may not have been the destination journal when the article was written seemed like a less subjective research decision. Another limitation was the split be- tween Zones 2 and 3. The calculated one third number of cumulative citations oc- curred between the lists of journals with the same number of citations. In the list, Zone 2 divided the group of journals cited nine times. Zone 2 was moved up to incor- porate only the journals with ten citations. Another researcher may have included all nine citation titles and therefore changed the makeup of the zone. As these journals make up the end of a last zone, the listing seemed less compromised by moving the zone up instead of down. 200 College & Research Libraries March 2014 Conclusion The importance of this study can be found in the Zone 1 journal listings. These twenty-three journals represent significant bodies of literature influential in the GIS disciplines. Librarians can use this list to cross-check their literature sup- port for GIS in the variety of subject areas around a campus and as a core title list when building a collection. The rate of use for older journal literature, particularly in these influential journals, can influ- ence decisions for retention, relocation, and back-file purchases to support GIS researchers. Collaboration in collection development is a must in a discipline with such breadth and reach. Creating a core list of journals for an emerging discipline, or one that crosses many disciplinary lines can be a great asset for librarians especially as they focus on user behavior to tailor services and instruction. Index- ing and abstracting tools are another area of collection development that is always under review and another area for col- laboration. Using the levels of coverage for Zone 1 and Zone 2 journals, a librarian can identify the best tools to either pur- chase or point to when GIS researchers are looking for journal literature. While several other core lists, Magazines for Libraries and the Caron et al. Delphi study provide additional lists, this study provides one based on citation data from core journals in the field. The Zone 2 list- ings are particularly important at the top of the list and reflect current trends in the application of GIS as well as its direc- tions. Using this list, and referring to an institution’s research areas, GIS can be more supported in the academic library. Librarians try to choose the best research for their patrons and often make those decisions based on journal package deals as well as recommendations from faculty. It is important to provide data to back up those decisions when approaching budget officers and selection managers for purchasing and deaccessioning. These data can supplement researchers’ recom- mendations and provide a solid basis for consideration. Future researchers could repeat this study using additional source journals and compare the results to those in this study to check for self-citation bias and new areas of research. Examining changing formats and especially the use of eBooks as well as the influence of specific conference proceedings as scenes of innovation are insights that could inform the literature. Notes 1. D. Kevin Davie, The ARL Geographic Information Systems Literacy Project: A SPEC Kit (Wash- ington, D.C.: Association of Research Libraries Office of Leadership and Management Services, 1999), 35–37. 2. Joseph A. Salem, Spatial Data Collections and Services (Washington, D.C.: Association of Research Libraries Office of Leadership and Management Services, 2005), 139–42. 3. Encyclopedia of GIS, eds. Shashi Shekhar and Hui Xiong (New York ; London: Springer, 2008), 578. 4. Samuel Clement Bradford, Documentation (Washington, D.C.: Public Affairs Press, 1950), 156. 5. Encyclopedia of Geography, Vol. 3, ed. Barney Warf (Thousand Oaks, Calif.: Sage Publications, 2010), 84–85. 6. Robert S. Allen, “Interdisciplinary Research: A Literature-Based Examination of Disciplinary Intersections Using a Common Tool, Geographic Information System (GIS),” Science & Technology Libraries 21, no. 3/4 (2001): 191–209, doi:10.1300/J122v21n03_12. 7. Anne L. Buchanan and Jean-Pierre V. M. Hérubel, “Interdisciplinarity: The Case of Histori- cal Geography through Citation Analysis,” Collection Building 14, no. 1 (1994): 15-21, doi:10.1108/ eb023390. 8. William C. Robinson and Paul E. Poston, “Literature Use by Geography Scholars,” Behavioral & Social Sciences Librarian 25, no. 1 (2006): 13–31, doi:10.1300/J103v25n01_02. 9. Andrew Bodman, “Weavers of Influence of Contemporary Geographic Research,” Transac- tions of the Institute of British Geographers 16, no. 1 (1991): 21–37, available online at www.jstor.org/ stable/622904 [accessed 18 February 2014] Mapping the Literature of GIS 201 10. J.W.R. Whitehand, “The Impact of Geographical Journals: A Look at the ISI Data,” Area 16 (June 1984): 185–87, available online at www.jstor.org/stable/20002055 [accessed 18 February 2014]. 11. Neil Wrigley and Stephen Matthews, “Citation Classics and Citation Levels in Geogra- phy,” Area 18, no. 3 (1986): 185–94, available online at www.jstor.org/stable/20002339 [accessed 18 February 2014]. 12. Robinson and Poston, “Literature Use by Geography Scholars,” 13–31. 13. David Lee and Arthur Evans, “Geographers’ Rankings of Foreign Geography and Non-Geography Journals,” Professional Geographer 37, no. 4 (1985): 396–402, doi:10.1111/j.0033- 0124.1985.00396.x. 14. Bodman, “Weavers of Influence of Contemporary Geographic Research,” 21–37. 15. Wrigley and Matthews, “Citation Classics and Citation Levels in Geography,” 185–94. 16. Robinson and Poston, “Literature Use by Geography Scholars,” 13–31. 17. Anthony C. Gatrell and Anthony Smith, “Networks of Relations among a Set of Geographi- cal Journals,” Professional Geographer 36, no. 3 (1984), doi:10.1111/j.0033-0124.1984.00292.x. 18. Ibid. 19. Claude Caron, Stéphane Roche, Daniel Goyer, and Annick Jaton, “GIScience Journals Rank- ing and Evaluation: An International Delphi Study,” Transactions in GIS 12 (June 2008): 293–321, doi:10.1111/tgis.2008.12.issue-3. 20. Ibid., 308. 21. Francis A. Delwiche, Barbara F. Schloman, and Margaret P. Allen, “Mapping the Literature of Nursing and Allied Health Professions: Project Protocol,” (2010). 22. Amber T. Burtis and Mary K. Taylor, “Mapping the Literature of Health Education: 2006–2008,” Journal of the Medical Library Association 98, no. 4 (2010), doi:10.3163/1536-5050.98.4.005; Jonathan Potter, “Mapping the Literature of Occupational Therapy: An Update,” Journal of the Medical Library Association 98, no. 3 (2010), doi:10.3163/1536-5050.98.3.012. 23. Institute for Scientific Information, “Help, Impact Factor,” Journal Citation Reports: JCR. Institute for Scientific Information, available online at http://admin-apps.webofknowledge.com/ JCR/help/h_impfact.htm [accessed 18 February 2014]. 24. Robert A. Buchanan, “Accuracy of Cited References: The Role of Citation Databases,” Col- lege & Research Libraries 67, no. 4 (2006): 292–303, available online at http://search.ebscohost.com/ login.aspx?direct=true&db=lih&AN=21788776&site=ehost-live [accessed 26 March 2012]; “Errors in Citation Statistics,” Nature 415, no. 6868 (2002), available online at www.nature.com/nature/ journal/v415/n6868/pdf/415101a.pdf [accessed 26 March 2012]. 25. Elsevier Science Publishers, “Help, Metrics” Scopus (2004), available online at http://help. scopus.com/flare/schelp_Left.htm#CSHID=h_jrneval.htm|StartTopic=Content%2Fh_jrneval. htm|SkinName=sc_help_rebrand [accessed 12 March 2012]. 26. Katherine H. Weimer, “Cartography, GIS and Imagery,” in Magazines for Libraries, ed. Cheryl LaGuardia (New York: ProQuest, 2010), 190–93. 27. Weimer, “Cartography, GIS and Imagery,” 191. 28. Ulrich’s Periodicals Directory (New Providence, N.J.: R.R. Bowker, 2001). 29. Bradford, Documentation, 156. 30. Delwiche, Schloman, and Allen, “Mapping the Literature.” 31. Ibid. 32. R.E. Burton and R.W. Kebler, “The ‘Half-Life’ of Some Scientific and Technical Literatures,” American Documentation 11, no. 1 (1960), doi:10.1002/asi.5090110105. 33. Pedro Albarrán and Javier Ruiz-Castillo, “References Made and Citations Received by Scientific Articles,” Journal of the American Society for Information Science and Technology 61 (Jan. 2011): 40–49, doi:10.1002/asi.21448. 34. Burtis and Taylor, “Mapping the Literature of Health Education: 2006–2008,” 297; Potter, “Mapping the Literature of Occupational Therapy: An Update,” 239. 35. Delwiche, Schloman, and Allen, “Mapping the Literature.”. 36. Robinson and Poston, “Literature Use by Geography Scholars,” 13–31. 37. Ibid. 38. Caron et al., “GIScience Journals Ranking and Evaluation,” 293–321. 39. Thomas E. Nisonger, “Journals in the Core Collection,” Serials Librarian 51, no.3/4 (2007), doi:10.1300/J123v51no03_05. 40. Robin A. Paynter, Rose M. Jackson, and Laura Bowering Mullen, “Core Journal Lists: Classic Tool, New Relevance,” Behavioral and Social Sciences Librarian 29 (2010): 15–31, doi:10.1080/01639260903571096. 41. Ibid. 42. Katherine Corby, “Constructing Core Journal Lists: Mixing Science and Alchemy,” portal: Libraries and the Academy 3 (Apr. 2003): 207–17, doi:10.1353/pla.2003.0029.