and possibly error prone if it involves a significant amount of manual tasks. Deeper integration provides a common interface and transparent file or information sharing and transfer between the respective components. Possible ways are the use of higher-level application language or application generators increasingly common as built-in features of commercial GIS packages as the basis of numerous integrated applications. Application generators and modeling capabilities with commercial GIS also offer the possibility of tight integration within the limits of the respective package options. An alternative is to use an open GIS tool kit, that uses a standardized interface, such as GRASS (Gardels 1988, Fedra and Kubat 1993).