Spatial-Query-by-Sketch

Funding Agency: Air Force Research Laboratory Principal Investigator: Max Egenhofer

Project Summary:

Today's methods for interacting with spatial databases are primarily aspatial, as they require the users to deal with geo-referenced data primarily through alphanumeric command languages. Currently, spatial querying is done by typing a command in some spatial query language, such as an extended version of SQL, or by selecting the same or a similar syntax from pull-down menus. Such spatial querying is a tedious process, because it often requires extensive training in the use of the particular query language, and forces users to translate a spatial image they may have in their mind into a non-spatial language. Graphical user interfaces provide only little improvement for such query languages, because they use the same type of syntax and grammar as the typed languages, and they only release users from remembering the particular syntax.

We propose to design an prototype Spatial-Query-by-Sketch, a sketch-based GIS user interface that focuses on specifying spatial relations by drawing them. It uses a more intuitive style of interaction with spatial data that is made possible by the advent of pen-based user interfaces and the increased interest in Mobile Computing. Rather than expressing a spatial query in lexical terms, users sketch a query in Spatial-Query-by-Sketch. This query style supports more directly human spatial thinking. This is critical, because users have frequently an image-like representation in their minds when they query about spatial configurations. Rather than forcing users to express such a situations in some (semi)-formal or natural language, it is a major step towards the successful use of spatial information systems if users are allowed to draw a sketch of the image they have in their mind, in order to retrieve the spatial data of interest.

This 2-year project will investigate the interaction and the query processing aspects associated with Spatial-Query-by-Sketch. The interpretation and processing of such a spatial query will be based on a solid theory of spatial relations, consisting of an extended version of the 9-intersection, a comprehensive model for topological relations. Software prototypes will be developed that will proof that the concepts developed from this theory are applicable.

Last updated on September 3, 1999.