Section 2.4.1.2.2 Field


User defined subclasses of Field describe the distribution of a single phenomenon over a given portion of space. The geometry of the spatial object for a field represents a continuous region in space. It may for example correspond to a set of isolines, a set of velocity vectors at irregularly spaced points, a triangulated irregular network, a regular grid or a digital elevation model. Because of the nature of a field, estimated values for a phenomenon at arbitrary locations may be determined through interpolation. The way in which the interpolation proceeds will depend on the kind of field and the particular spatial representation being used.

2.4.1.2.3 PartitionedCoverage

User defined subclasses of PartitionedCoverage are applicable where the coverage consists of a series of discrete features, such as forest stands or census tracts, or combinations of discrete features, such as roads and railroads. The features composing the coverage are not necessarily space filling. Areal features (such as forest stands) in a 2D space cannot overlap, and similarly, volumetric features (such as ore bodies) in a 3D space cannot overlap.

In some situations such overlap may reasonably exist, as with a map showing both surface and subsurface rights. Such a situation can be handled in different ways. The surface rights may represent one partitioned coverage and the subsurface rights another. If it is desirable to treat both coverages together, they can both be incorporated into a spatial composite (as described later). The surface and subsurface rights may be integrated into a single partitioned coverage only if an overlay (i.e. intersection) procedure has been carried out, such that every resultant area has a value for both surface and subsurface rights.


Links to the SAIF 3.1 Specification document and the complete SAIF class list