![]() ![]() This was one of the primary threads that formed the subdiscipline of geographic information science in the early 1990s.įurther developments in GIS data modeling in the 1990s were driven by rapid increases in both the GIS user base and computing capability. Īs commercial off-the-shelf GIS software, GIS installations, and GIS data proliferated in the 1980s, scholars began to look for conceptual models of geographic phenomena that seemed to underlay the common data models, trying to discover why the raster and vector data models seemed to make common sense, and how they measured and represented the real world. This led to efforts at the Harvard Lab and elsewhere focused on developing a new generation of generic data models, such as the POLYVRT topological vector model that would form the basis for commercial software and data such as the Esri Coverage. During the 1970s, the early systems had produced sufficient results to compare them and evaluate the effectiveness of their underlying data models. Most first-generation GIS were custom-built for specific needs, with data models designed to be stored and processed most efficiently using the technology limitations of the day (especially punched cards and limited mainframe processing time). Unlike CGIS, these were all raster systems inspired by SYMAP, although the MLMIS was based on subsections of the Public Land Survey System, which is not a perfect regular grid.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |