A directional
spatial relationship to a reference object (e.g., “east of the post
office”) can be represented by a spatial template. The template
partitions the space into regions where the relationship holds (to
various extents) and regions where it does not hold. The objects for
which the relationship holds can then be located. A template can be
easily modeled. Computationally, however, exact calculation of the
model in case of 2D raster data is prohibitively expensive, and a
tractable approximation algorithm was proposed. Here, we introduce a
new concept: the concept of the Ftemplate. It leads to a new
approximation algorithm, which is faster, gives better results, and is
more flexible.
