Only the file formats and the corresponding input and output routines, usually of the model, have to be adapted.
Depending on the implementation however, a solution based on files
shared between two separate applications, usually with a different user
interface, is cumbersome 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).