| In spite of considerable interest in using geographic information systems (GIS) in support of environmental modeling, there has been only limited success with integrating GIS and hydrologic models. Technical, semantic, and institutional barriers can cause such a problem. Technical barriers are mainly related to format incompatibility. They are considered a trivial barrier given the extensive research conducted on this issue.; This dissertation hypothesizes that semantic barriers, i.e., misunderstandings of meanings, are the major type of barrier in the integration of GIS and hydrologic models. The goal of this research is to provide a better explanation of the problems facing the integration of GIS and hydrologic models and thus provide guidance toward solving such problems. The probe of institutional barriers is beyond the scope of this study.; Identification of semantic barriers requires comparisons between concepts commonly used in GIS and those used in surface hydrology. Such comparisons require a list of concepts in both GIS and hydrologic models that are semantically rich and internally consistent. Concepts commonly used in GIS were extracted from the United States Spatial Data Transfer Standard. Concepts for surface hydrology were extracted through an analysis of three representative hydrologic models, i.e., HEC-HMS, TOPMODEL, and BLTM. Two tools were used during the extraction of those surface hydrology concepts. First, SNAP/SPAN Ontologies was used to help organize those concepts. Following that Haskell was used to test the consistency and completeness of the results.; The study identified many potential semantic barriers between concepts in GIS and hydrologic models. They fall into five categories: (1) multiple terms that refer to the same concept, (2) inconsistently applied typing system employed in the categorization of concepts, (3) one term that refers to multiple similar concepts, (4) one term that carries an ambiguous concept, and (5) two concepts that partially overlap in meanings. The study found that while it is possible to remove semantic barriers of the first and second types, it is difficult to remove the last three types of semantic barriers. The study therefore concludes that semantic barriers remain a major obstacle toward the integration of GIS and hydrologic models. |
