The article by Stephen J. Carver discusses the integration of multi-criteria evaluation (MCE) techniques with geographical information systems (GIS) to enhance decision-making in spatial planning, particularly in the context of site selection for radioactive waste disposal. The author highlights the limitations of traditional GIS, which are primarily suited for deterministic analyses and area screening using map overlays. MCE techniques, on the other hand, are well-suited for evaluating multiple and conflicting criteria and objectives, making them valuable additions to the GIS toolset. The paper outlines the basic principles of MCE, including the construction of an evaluation matrix, standardization of criterion scores, and the use of criterion weights. It also describes three MCE methods—ideal point analysis (IPA), hierarchical optimization (HO), and concordance-discordance analysis (CDA)—and their application within a GIS framework. The author emphasizes the importance of data handling and the need for a user-friendly interface to integrate MCE routines into GIS. A practical example is provided, demonstrating how the combined GIS-MCE approach is applied to identify suitable sites for radioactive waste disposal in the UK. The example illustrates the process from initial survey using GIS overlays to preliminary site identification through MCE techniques. The results highlight the need for sensitivity analysis to account for variations in technique and priority bias, leading to the identification of robust sites. The author concludes that the integration of GIS and MCE offers significant advantages in making complex and controversial decisions, particularly in spatial decision support systems (SDSS). This approach can provide a more rational, objective, and non-biased decision-making process, enhancing the capabilities of GIS in spatial planning and decision support.The article by Stephen J. Carver discusses the integration of multi-criteria evaluation (MCE) techniques with geographical information systems (GIS) to enhance decision-making in spatial planning, particularly in the context of site selection for radioactive waste disposal. The author highlights the limitations of traditional GIS, which are primarily suited for deterministic analyses and area screening using map overlays. MCE techniques, on the other hand, are well-suited for evaluating multiple and conflicting criteria and objectives, making them valuable additions to the GIS toolset. The paper outlines the basic principles of MCE, including the construction of an evaluation matrix, standardization of criterion scores, and the use of criterion weights. It also describes three MCE methods—ideal point analysis (IPA), hierarchical optimization (HO), and concordance-discordance analysis (CDA)—and their application within a GIS framework. The author emphasizes the importance of data handling and the need for a user-friendly interface to integrate MCE routines into GIS. A practical example is provided, demonstrating how the combined GIS-MCE approach is applied to identify suitable sites for radioactive waste disposal in the UK. The example illustrates the process from initial survey using GIS overlays to preliminary site identification through MCE techniques. The results highlight the need for sensitivity analysis to account for variations in technique and priority bias, leading to the identification of robust sites. The author concludes that the integration of GIS and MCE offers significant advantages in making complex and controversial decisions, particularly in spatial decision support systems (SDSS). This approach can provide a more rational, objective, and non-biased decision-making process, enhancing the capabilities of GIS in spatial planning and decision support.