The exact site for a building should not be based solely on the soils map. It is important to understand the type of data you are modeling, whether it be continuous or discrete, when making decisions based on the resulting values. No matter where on the continuum the feature falls, the grid-cell storage can represent it to a greater or lesser accuracy. ![]() The determining factor for where a feature falls on the continuous-to-discrete continuum is the ease of defining the feature’s boundaries. Illustrations of features that fall along the continuum are soil types, edges of forests, boundaries of wetlands, and geographic markets influenced by a television advertising campaign. Most features fall somewhere between the extremes. A continuum is created in representing geographic features, with the extremes being pure discrete and pure continuous features. Other locomotion surfaces include dispersal of animal populations, potential customers of a store (cars being the means of locomotion and time being the limiting factor), and the spread of a disease.įor many objects, their boundaries can be represented and modeled as either continuous or discrete. The means of locomotion, whether it be bees, man, wind, or water, all affect the surface concentration of seed dispersal for the plant. Mode of locomotion can also limit and directly affect the surface concentration of a feature, as is the case with seed dispersal from a plant. For example, the movement of the noise from a bomb blast is governed by the inherent characteristics of noise and the medium it moves through. Another type of concentration surface is governed by the inherent characteristics of the moving phenomenon. In the source-concentration surface above, the concentration of the phenomenon at any location is a function of the capability of the event to move through the medium. The concentration is always greater near the source and diminishes as a function of distance and the medium the substance is moving through. ![]() In this type of continuous surface, there has to be a source. Surface characteristics of this type of movement include salt concentration moving through either the ground or water, contamination level moving away from a hazardous spill or a nuclear reactor, and heat from a forest fire. The first type of movement is through diffusion or any other locomotion in which the phenomenon moves from areas with high concentration to those with less concentration until the concentration level evens out. These surfaces are characterized by the type or manner in which the phenomenon moves. Illustrations of progressively varying continuous data are fluid and air movement. ![]() These include elevation (the fixed point being sea level) and aspect (the fixed point being direction: north, east, south, and west).Īnother type of continuous surface includes phenomena that progressively vary as they move across a surface from a source. One type of continuous surface is derived from those characteristics that define a surface, in which each location is measured from a fixed registration point. Continuous data is also referred to as field, nondiscrete, or surface data. Discrete objects are usually nouns.Ī continuous surface represents phenomena in which each location on the surface is a measure of the concentration level or its relationship from a fixed point in space or from an emitting source. Other examples of discrete objects include buildings, roads, and parcels. Where the water’s edge meets the land can be definitively established. A lake is a discrete object within the surrounding landscape. A discrete object has known and definable boundaries: it is easy to define precisely where the object begins and where it ends. Discrete data, which is sometimes called thematic, categorical, or discontinuous data, most often represents objects in both the feature (vector) and raster data storage systems.
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