GIS Basics - Why Use ESRI's ArcGIS?

The choice of which GIS software package to employ is as important as the use of the software itself. Three major considerations present themselves when selecting a GIS package: cost, functionality and system requirements, and ability to exchange data with others. Currently, four major GIS software packages compete for market shares in the GIS world: Environmental Systems Research Institute (ESRI) founded in 1969 makers of ArcGIS, Clark Labs founded in 1987, makers of Idrisi; MapInfo founded in 1986, makers of MapInfo; and Golden Software formed in 1983, makers of Surfer®. Each of these four companies and their associated software packages currently enjoy success in a range of markets. ArcGIS is certainly the industry standard for GIS and remains the fastest-growing and most-widely used software package in the world. The ESRI website states that its software is used by “more than 300,000 organizations worldwide including most U.S. federal agencies and national mapping agencies, 45 of the top 50 petroleum companies, all 50 U.S. state health departments, most forestry companies, and is the standard in state and local government used by more than 24,000 state and local governments including Paris, France; Los Angeles, California, USA; Beijing, China; and Kuwait City, Kuwait” (ESRI Website: May 2005).

A perspective GIS user’s first consideration is most often the price of these different software packages. ArcGIS and Idrisi software packages both offer educational discounts. The price for the central system component and extensions are outlined in Table 4-1 (GIS software packages typically have a ‘core’ program that has expandable functionality through add-on ‘extension’ programs, unfortunately prices for the MapInfo extensions was not available even after contacting numerous people at MapInfo).

Retail and Educational Prices for Leading GIS Software Packages (current May 2005)

Software packages purchased at the individual level are comparable, and price becomes negligible for the student or individual buyer (corporate prices are not included here, even though they are typically how universities and CRM firms would purchase the software).

The next consideration, after price, is functionality and system requirements. Defining appropriate functionality is difficult due to the various needs and expectations of users. For instance, any of these products will create two-dimensional maps with data collected by a total station or a GPS receiver. They each have interfaces that run in a Microsoft Windows environment, and purchased versions include supporting literature. However, only ArcGIS and MapInfo have online tutorial courses to ‘walk’ a user through the software.

These online courses range in price from $0 to $150. The online courses for ArcGIS are free if an institution or company that owns a site-license, granting a large number of user-licenses for individual machines on a computer-network (e.g. at a university). The Surfer® program is specifically designed for generating realistic 3D terrain maps. To construct these types of virtual re-constructions with other ArcGIS and MapInfro requires expensive extension programs, unless purchased at the educational discount. Ultimately, the functionality of these software packages from an archaeological standpoint is equal as each program will create standard two-dimensional maps, complete basic database-style queries of the data, carry out simple geostatistical analysis (such as slope), and even cast 3D views of landscapes (sometimes requiring an extension program). Surfer® stands out due to its very specific design, focusing on the creation of 3D representations of data. In other words, complex GIS functions such as geocoding addresses (assigning a street address to spatial coordinates) are absent from this software package. Also, Idrisi’s focus on image manipulation, which makes it ideal for dealing with remote sensing data, means that it has limited appeal to the larger GIS community who rarely require advanced image manipulation (although MapInfo and ArcGIS have extensions to accomplish this).

The system requirements of each software package are similar, with the exception of Surfer®. All require Windows 98, Me, 2000, XP, or higher operating systems. Typical RAM vary somewhat; Surfer® recommends 64 MB, while the other programs recommend 512 MB. The larger requirements of the other software packages reflect the limited functionality of Surfer®, which focuses on creating 3D views. Surfer® also requires the least amount of hard disk space to install, at only 25 MB it requires a fraction of the 500-600 MB required by ArcGIS, Idrisi, and MapInfo. Again, these larger requirements reflect the increased functionality of these other programs. The system requirements of most of these software packages has become a moot point as recent microcomputer arrangements have far surpassed these requirements. In fact, an off-the-shelf laptop (retailing for $1,000) or a desktop computer (retailing for $700) from most electronic stores have sufficient system resources to effectively make use of these programs.

Therefore, the defining factor that drives most GIS professionals to choose ESRI products centers on its wide-spread use. As mentioned previously, ESRI products dominate – with all the positive and negative connotations that implies – the GIS marketplace. Some estimates place ESRI’s share of the GIS market at more than eighty percent (ESRI website, 2005). This is partially a reflection of the earlier history of ESRI as a company. Founded in 1969, this company has grown and actively defined the uses of GIS in a variety of industries, designing extension programs that address specific needs of certain businesses (i.e. surveyors, city planners, utility companies, etc.).

However, ArcGIS has not completely cornered the archaeology market, and many archaeologists continue to use other programs. Kenneth Kvamme continues to use Idrisi for complex image analysis of remote-sensing data (i.e. ground-penetrating radar, resistivity, conductivity, etc.) in his work at the Center for Advanced Spatial Technologies (CAST) at the University of Arkansas. Nigel Chang in the University of Otago’s Department of Anthropology maintains that MapInfo satisfactorily creates two-dimensional maps for his research into the Iron Age of Southeast Asia. Jerry Hilliard at the Arkansas Archaeological Survey has recently begun using Surfer® to virtually re-construct archaeological landscapes for use in report preparation and public outreach.

Ultimately, my decision to use ESRI’s ArcGIS centers on two factors: its availability to students at most universities (thanks to campus-wide site-licenses held by one or more departments on campus), and my familiarity with the software due to four semesters of coursework making use of ArcView 3.2 and 3.3, ArcGIS version 8.2, 8.3, and 9.0. The facts that ArcGIS enjoys a dominant role in the GIS industry (both domestically and abroad), is used by more federal and local agencies than any other program, and contains numerous tools for importing and exporting data between formats are all beneficial side-effects.

Obviously, the individual abilities of each of these software packages cannot be completely explored in such as short space and might require a thesis all its own. However, the basic concepts of GIS outlined in the next section is not ESRI specific and could be applied to a general examination of any GIS software package.