The design rationale is a critical component of any GIS project, serving as the explicit documentation of the decisions made throughout the design process and the reasoning behind those decisions. It is not merely about recording choices; it’s about understanding the implications of those choices, providing a clear rationale that can guide future decisions, ensure consistency, and facilitate feedback and improvement.
In a GIS project, the design rationale covers several key areas:
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Ontology Choices: The rationale explains why certain ontologies were chosen to define the world of discourse for the project. It should detail the reasons for these choices, including how they align with the project’s goals and the implications for data categorisation and analysis.
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Data and Analysis: The design rationale should document the selection of datasets and the analytical methods employed. It must address why specific datasets were used, whether existing data was deemed sufficient, or why new data collection was necessary. Additionally, it should outline the chosen analytical approaches, consider alternatives, and explain why particular methods were preferred.
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Visualiaations: The rationale also includes the design choices for visualisations—why certain types of maps, charts, or other visual tools were used to communicate the project’s findings. This includes considerations of how these visualisations align with organisational design standards or branding requirements.
One key purpose of the design rationale is to clearly explain the consequences or artifacts created by different choices. By explicitly documenting the trade-offs and potential impacts of various decisions, the rationale helps avoid unintended consequences and ensures that all stakeholders understand the implications of the project’s design.
Moreover, the design rationale is essential for documentation and feedback. It provides a structured record that can be referenced throughout the project’s lifecycle, making it easier to review decisions, provide feedback, and make adjustments as needed. It also serves as a valuable resource for future projects, offering insights into the decision-making process and the outcomes of past choices.
In alignment with the concept developed by W.R. Kunz and Horst Rittel, the design rationale in a GIS project provides an argumentation-based structure that supports the collaborative and often complex process of designing geospatial systems. It ensures that decisions are not only recorded but also justified, considering all alternatives and trade-offs, ultimately leading to more robust and well-founded project outcomes.
By maintaining a clear and detailed design rationale, GIS professionals can enhance the transparency, consistency, and effectiveness of their projects, ensuring that the reasoning behind every decision is well-documented and understood.
There is an excellent article on design rationals in general on Wikipedia on design rationals