Geospatial Industry

Data Production Technologies

Geospatial data are the spatially referenced, geometric features, images, and associated attribute values that can be visualized on a hard-copy or digital map. Traditional methods for creating spatial data, such as land surveying and manual drafting and digitizing, are still practiced; however, many techniques are being replaced by automated or computer-aided data capture and processing. Remote sensing, in particular, has revolutionized the way in which many forms of spatial data are created.

Remote sensing is predominantly accomplished by means of two platforms: aerial sensors and satellite sensors. The initial product of most remote sensing instruments is a raster (a regular array of grid cells) image of Earth's surface. By themselves, satellite and aerial imagery are critical components of most data consumers’ libraries of information. In addition, aerial imagery has become the foundation from which other data are derived. In particular, vector data (geometric features composed of points, lines, and polygons) such as roads, streams, and building footprints can often be manually or automatically digitized from imagery with greater accuracy, speed, and convenience than can be achieved by traditional methods. The advantages of raster imagery combine to make the remote sensing industry an indispensible asset to nearly all geospatial endeavors.

Another data production technology that has revolutionized the geospatial industry is the global positioning system (GPS). The GPS is, in essence, a data production technology, due to the fact that its fundamental role is to produce the coordinate location of a receiver. With the addition of differential GPS and the Wide Area Augmentation System (WAAS), receivers can yield ground coordinates within fractions of an inch of their true position. GPS satellites were initially launched by the U.S. government for military applications, and an intentional degradation of the positioning accuracy, called Selective Availability, was installed to prevent nonmilitary receivers from attaining high accuracies. Selective Availability has since been deactivated, allowing commercial and recreational receivers to achieve higher accuracies, thus enabling the expansion of the geospatial industry into the realm of location-based services (LBS), which are discussed later in this entry.

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