Print this pageGIS Data Models for Geology
McCOLLOCH, JR. GAYLE H.
A variety of spatial data models can be applied to different aspects of geology. The simple vector data models found in various Computer Aided Drafting (CAD) programs are sometimes used for routine mapping and some simple analyses. However, more sophisticated applications that maintain the topological relationships between cartographic elements enhance analytical potential. Also, vector data models are best for producing various types of high quality, conventional maps.
The raster data model is generally considered best for representing data that varies continuously over a geographic area, such as the thickness of a coal bed. Information is lost when contour lines are threaded through raster grids for display, so volumes and tonnages are more accurately determined by working directly with raster data. Raster models are especially well suited to computationally simple surface-to-surface analysis, or overlay functions.
Another data model, triangulated irregular networks (TINs) are superior at portraying visible surfaces because many TIN programs support break lines. Break lines locate sharp breaks in slope such as those generated by bodies of water or ridge crests. TINS also "honor" data points so that a surface generated from a set of points will be forced to pass through those points. TINs ,or grids generated from TINs, are particularly good at determining the intersections of surfaces such as coal seam outcrops and geologic unit boundaries.
No single technique works best for all applications. The ability to use a variety of data models and transform from one model to another is essential for obtaining optimum results in a timely manner.