It must first be recognized that GIS and automated mapping have demonstrated their effectiveness in the public and private sectors for routine administrative and management applications. You see ample evidence of this at the meetings of the several organizations concerned with this field, and the demand for software has led to the establishment of a number of commercial GIS vendors. It is these non-routine tasks that are the subject of this brief essay. One reason is presumably because planning is rarely a routine task. The terms long used in geographic theory for these contrasting approaches are nomothetic and ideographic.
Planning theory recognizes a similar dichotomy, although less clearly defined.
One may argue that such data could simply be added as more layers, and technically that may be the easiest way to deal with singular or infrequent data. However, I suggest this should be viewed as allowing a variable number of attributes for every entity in a GIS, and further, a variable number of entities for every spatial location. Coupled with this exception orientation are a set of processing tools and a user interface that operate on and display places, sites or regions, rather than the factors that describe them. Subsequent commands in a place-oriented GIS might center on grouping into place categories, based on their similarities in description, their size, or their spatial relationships to neighbors. There are a number of less necessary but desirable features for a place-oriented GIS, for example the incorporation or linkage to a variety of data formats, such a a text description, a statement about some occurrence or special meaning of the location, a sketch or diagram, or photographs stored on a CD or similar media.