Object-relational Datamodel Components for Geologic Mapping Conduct

Processes of terrestrial geologic mapping and preparation of geologic maps are supported by Geographic Information Systems (GIS) and respective datamodels of which an assessable number are currently available. Such datamodels help mappers to define spatial geologic map units by integrating field and remote-sensing information and relate them to non-spatial information about unit details, in particular rock composition, age and age relationships, attitude data, and other characteristics. Apart from any interpretive tasks concerned with the delineation of various surface units in terms of geological and geomorphological boundaries and contents, basic mapping tasks involve an efficient management of attribute data needed for (1) applying an assignment of standardized cartographic symbols or color schemes, (2) performing spatial queries and data analyses, or for (3) combining and homogenizing mapping results generated by different groups. A unit usually carries multiple assignments to which an appropriate cartographic symbology representation is related. Such an assignment may describe the surface unit material, its stratigraphic name and relative position, or its chronostratigraphic and absolute position. The assignments of surface materials or the assignments of stratigraphic units within or without an absolute chronologic context and the subsequent selection of cartographic symbols can usually be handled using a standard geologic relationship model for which surface materials are the most important attributes. The complexity grows significantly if a data model needs to be employed which is capable of dealing with all such requirements at the same time and which is able to guide the mapper through entities and attribute values by employing object-relational concepts. We here present a geologic mapping data model design that has been implemented within Environmental Systems Research Institute’s (ESRI) ArcGIS environment for systematic mapping conduct of different planetary surfaces. The model copes with each planet’s specific stratigraphic system, surface chronologies, specific naming conventions, and different body references. Additionally, standards developed by the Federal Geographic Data Committee (FGDC) for cartographic symbols in geologic mapping have been implemented on an abstract level and are incorporated via subtype-domain controls to achieve a high level of integrity of attribute data.