ABSTRACT
Over the last two decades , the collection of digital spatial data has grown beyond the few early adopters to virtually all resource management, facility management, and governing organizations in the United States. In 2001, for example, the combined expenditures for software in the geospatial industry exceeded a billion dollars (DaraTech, Inc. 2002). Over the last fifteen years, the industry has spent more than $3.5 billion on the collection and maintenance of digital spatial data. Data were collected both in raster imagery form as well as detailed vector databases to support general mapping, facility management, resource management, visualization, and spatial analysis. Raster data are features that are represented by pixels—a value that corresponds to a particular feature (National Research Council 1998). Most remotely-sensed data are raster data sets. Examples include surface temperatures, land use/land cover, digital elevation models, snow coverage, and nighttime illumination. Vector data represent features as points, lines, and polygons. For example, a point represents a city, a line a city street, and a polygon represents the area served by the city water supply system. The uses for these data across the nation are many and varied, as shown in Table 4.1.1. Spatial Data Themes
|
Theme |
Example |
|---|---|
|
Streets |
City, suburban, rural roads |
|
U.S., Canada, Mexico |
|
|
Administrative |
Cities, counties, states |
|
U.S., Canada, Mexico |
|
|
Demographics |
Current census demographic statistics and geographies, business demographic statistics by census geographies |
|
Business Locations |
Business facilities identified by Standard Industrial Classification (SIC) Codes |
|
Points of Interest |
National, state, and local parks, shopping malls, amusement parks, financial districts, public health facilities |
|
Lines of Communication |
Highways, railway lines, subway lines, bus lines, telecommunication lines, telecommunication hubs, natural gas pipelines, electrical transmission lines, bridges, flight paths, navigation equipment |
|
Transportation |
Airports, harbors, ports, rail yards, trucking depots, bus stations. |
|
Natural Resources |
Rivers, streams, lakes, forests, swamps, marshes, geology |
|
Environmental |
Ecosystems, hazardous sites, habitats, weather |
|
Agriculture |
Soils, crops |
|
Industry |
Power plants, refineries, factories |
|
Imagery |
High resolution, current black & white/color |
|
Digital Elevation Model |
High resolution |
