Geographic Bounding Box

The fundamental geometric description for any dataset that models geography. GeoBndBox is the minimum box, defined by west and east longitudes and north and south latitudes, that includes the largest geographic extent of the dataset's geographic coverage. This element is used in the first pass of a coordinate-based search. If the boundPoly element is included, then the geoBndBox element MUST be included.

Replication of the element geoBndBox is NOT recommended. The purpose of a bounding box is to support high level geographic point search systems. Most search systems of this type do not handle multiple instances of a bounding box. The bounding box should represent the full geographic coverage extent of the of the overall datasets being described by the Codebook instance. If there is a desire to provide the equivalent of a bounding box for each of multiple summary descriptions, use of the boundPoly is recommended. First provide a geoBndBox for the full area covered by the study. Then provide a boundPoly for each geographic area defined with a separate sumDscr. Note that when describing a bounding box using a boundPoly description the four corner points are described. The starting point and end point should match (closing the polygon).

The examples shown here show bounding box specifications for the coverage of two different data files.