An integrated terrain modeling system is disclosed. The integrated terrain modeling system has a site module. The site module includes a database having a terrain model of a site. The integrated terrain modeling system has a first field unit which includes a sensor operable to generate geodetic data of the site formatted in a first format. The system also has a further field unit which includes a sensor operable to generate geodetic data of the site formatted in a further format. The integrated terrain modelling system has an integration system operable to manipulate the geodetic data generated by the first filed unit and the further filed unit to be in a common format, thereby to provide seamless integration of the geodetic data at the site module to update the terrain model.