GEOG 468
GIS Analysis and Design

Marble and Wilcox Methodology: Looking Toward Software Engineering Practice


Marble and Wilcox developed a methodology that combines the Calkins methodology with concepts from software engineering and stresses the importance of involving all levels of an organization in the design process (Marble and Wilcox 1991). Figure 2.03 indicates the different parties that Marble and Wilcox recommend for participation in the process. These parties include members from within the organization as well as external parties relevant to the process. The external parties supplement the expertise and knowledge of the organization. This expertise includes knowledge of specific GIS software and digital data products and knowledge of the design process itself. The interaction of all of these parties contributes to the success of a GIS implementation project.

Figure 2.04 is a generalized diagram of the Marble and Wilcox methodology. The first step of functional and organizational feasibility is emphasized in this methodology. During this step not only are the objectives and requirements for the system defined, but the organizational implications of the system are also assessed (Marble and Wilcox 1991). The role that the system will play in the organization, the impacts the system will have on its members, the need for and value of implementing a GIS, and other such issues are addressed and made known to all members of the organization. This process of planning for both the technical and organizational specifications and impacts greatly reduces the possibility of later difficulties.

The explicit identification of organizational factors is the cornerstone of a successful GIS implementation according to the Marble and Wilcox methodology. The general ordering is similar to the other methodologies, but the emphasis is distinctly different. Listed below are a number of the specific issues that are stressed in this methodology (Marble and Wilcox 1991, pp. 9-11):

  • The design must explicitly define any changes in the structure of the organization, especially with respect to those areas directly affected by the implementation of the GIS.
  • The designer should produce not the most technically elegant solution, but the best technical solution that will realistically function within the organization.
  • The staff must view the GIS as both valuable and non-threatening.

The Marble and Wilcox methodology is significant with regard to its emphasis on the organizational aspects of GIS design and implementation. A factor that seems to be lacking, however, is a feedback mechanism to account for the incremental discovery of requirements. It is an overall linear process with no opportunity to return to the fundamental step of system objectives and requirements definition.

Figure 2.05 shows a detailed graphical description of the methodology. In this diagram, a step for optional pilot studies is shown. The omission of this step introduces risk by not allowing for feedback and incremental discovery of system requirements. The pilot study step consists of a reduced version of the entire methodology, where a physical product is generated, usually consisting of a simplified database and some commercial GIS software package acquired for evaluation purposes. The users evaluate the pilot system and reassess their needs and requirements. Feedback mechanisms and the implementation of the pilot system are key means to ensure that the requirements are correct and the ultimately implemented system is appropriate.

The Marble and Wilcox methodology, however, lacks an explicit education process. As stated earlier, the users cannot accurately assess their needs unless they are acquainted with the technology and understand its concepts. An initial step that consists of training and education is essential for an accurate definition of requirements. The pilot system will also provide a significant amount of education for the users as they interact with the system.

Marble and Wilcox strongly encourage broad organizational participation and illustrate this in a diagram (see Figure 2.03). By emphasizing the participation of many participants, Marble and Wilcox also address the communication requirement. The iterative discovery requirement is only partially addressed by Marble and Wilcox. There is no significant feedback mechanism back to requirements definition; however, an optional pilot study is included. This pilot study, if required and made a more prominent component of the methodology, would yield a better definition of requirements. The requirements of effective group work environments and education are not explicitly addressed in this methodology.