Annotating Uncertainty in Geospatial and Environmental Data

The Geography Markup Language (GML) -- the existing standard for encoding geospatial data -- has no mechanism for annotating such data with uncertainty. To address this issue while supporting the geospatial community's existing data and service standards, the authors extend GML to enable uncertainty markup. They demonstrate this extension's use with some common geospatial data types and Web services. The result is a robust capability to share error information while maintaining compatibility with existing geospatial data clients.