An efficient method and apparatus for regulating access to information objects stored in a database in which there are a large number of users and access groups. The invention uses a representation of a hierarchical access group structure in terms of intervals over a set of integers and a decomposition scheme that reduces any group structure to ones that have interval representation. This representation allows the problem for checking access rights to be reduced to an interval containment problem. An interval tree, a popular data structure in computational geometry, may be implemented to efficiently execute the access-right checking method.

The invention involves selecting a path through a multi-dimensional hyper-cube from a base vertex to an opposite corner or vertex of the hyper-cube. The path is selected by ranking the fractional components of the point or value to be interpolated. An N-dimensional interpolation is performed according to this sequence. During an interpolation a base vertex for an input color value is determined. The output value for the base vertex is accumulated. The fractional values of the input color value are sorted and ranked according to magnitude to produce an interpolation sequence. The interpolations are performed for each axis of the N-dimensions by selecting an axis for interpolation based on the order, performing an interpolation corresponding to the selected axis producing an interpolation result, and accumulating the interpolation result.

In apparatus and method for navigating a mobile body such as an automotive vehicle along a set route of travel, a road map stored in an external large-capacity memory unit such as a CD-ROM on a two-dimensional plane is graphically drawn on a display frame of an image screen with a degree of particulars of the road map data varied according to a displayed position of the image screen with respect to the display frame so that the graphically drawn road map in a form of a bird's eye view is viewed three-dimensionally with a feeling of depth given to a viewer. In an embodiment, as the displayed position of the image screen becomes upper with respect to the display frame, the degree of the particulars becomes lower.

A fixed or mobile image capturing device, coupled to a first computer, is remotely controlled over a global computer network by a second computer, and obtains a digital image of a scene. The first computer acquires a digital elevation model of the scene, which is data for creating a three-dimensional perspective model of the scene in two dimensions based on data corresponding, and registers the image with the digital elevation model. The registered digital image is provided to the second computer over the global computer network. When a user at the second computer points to an area of the registered image, the first computer augments the image provided with at least some information corresponding to the area pointed to.

A system and method for determining the boundaries of a field is disclosed. The system and method utilizes computational geometry and, in particular, the alpha shape of the field to derive the field boundary of a set of georeferenced data points. The method includes collecting georeferenced data for the field, assigning the georeferenced data to a data set, filtering the data to remove anomalous data points, filtering the data to remove known inside points, scaling the point coordinates from decimal to integer form, determining the alpha shape of the set, buffering the alpha shape to compensate for antenna position, and outputting the field boundary.