Topology allows many GIS operations to be done without accessing the point files. TINs use an optimal Delaunay triangulation of a set of irregularly distributed points. TINs are popular in CAD and surveying packages. Triangulated Irregular Network Way to handle field data with the vector data structure. More efficient than a grid.
Data formats can be industry standard, commonly accepted or standard.
Vector Data Formats Vector formats are either page definition languages or preserve ground coordinates. Most raster formats are digital image formats. If a GIS supports many data structures, changing structures becomes the user s responsibility. Data also are often exchanged or transferred between different GIS packages and computer systems. The history of GIS data exchange is chaotic and has been wasteful.