Search: 
Location Analysis: 
Terrain Analysis: 
Distribution/ 
Neighborhood: 
Spatial Analysis: 
Measurements: 
Interpolation 
o 
Buffer 
Multivariate Analysis 
Thematic Search 
Corridor 
La 
Catchment/Basins 
Proximity 
Pattem/Dispersion 
Æ 
Spatial Search 
r^SSF 
]£.I 
Overlay 
Drainage/Network 
Q- 
Nearest Neighbor 
V/ 
rJ: 
Centrality/Connectedness 
(Re-)classification 
ThiessenA/oronoi 
Viewshed Analysis 
Shape 
Measurements 
Figure 1. The 20 universal analytical GIS operations 
3 The VGIS Concept 
VGIS is not intended to be yet another GIS. It is conceived as a shell that can be draped over an existing GIS, 
using the function offered by that GIS (see Figure 2). The current implementation requires one interpreter for 
each existing GIS, but the prospect of vendors adhering to the OGF's Open Geodata Model alleviates this 
necessity. Then VGIS could become a generally valid tool for all OGIS compliant GIS. 
The VGIS-Shell consists of four modules: 
• the graphical user interface (GUI) 
• an interpreter for the processing plans 
• a tool to generate the processing plans 
• the underlying of-the-shelf GIS 
3.1 The Graphical User Interface 
Compared to regular GIS user interfaces there are a number of significantly different features that cause the 
innovative user friendliness of VGIS: 
• Complete configurability of the user interface 
The GIS manager has complete freedom to adjust the user interface to the needs of his customers. Only 
those operations that are useful to solve the users' task will be offered. Their structure and presentation in