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Lesson Navigation IconFundamental spatial concepts

Unit Navigation IconThe Scale

Unit Navigation IconGeoreferencing: Positioning and Projections

LO Navigation IconGeoreferencing

LO Navigation IconMap Projections

LO Navigation IconPositioning

Unit Navigation IconSpatial Relations

Unit Navigation IconTopology, fundamental concept

Unit Navigation IconSpatial Distance and Properties of the Environment

Unit Navigation IconGlossary

Unit Navigation IconBibliography

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Georeferencing: Positioning and Projections

The location of objects in space describes both, its position in space as well as its relation to other objects. The location includes two concepts: The position and the neighborhood. In everyday life, the notion of neighborhood is often used to locate objects; for example, one would say that the grocery store is located next to the church. In this example, location involves the concept of neighborhood, the measuring of proximity in relation to a reference object whose position is perceived implicitly. Obviously, such a location does not fit to the description of a set of complex objects such as those described in GIS. In GIS the requirements are even higher as they were for conventional mapping. In this case, one talks about the positioning of objects on the terrestrial surface. The establishment of a reference system and the definition of a metric space to measure distances are necessary. The simplest and most frequently used system is the Euclidean metric. The space is assumed to be flat; the metric space is assumed to be constant, defined by a perpendicular axis system. The mapping systems based on this principle are adopted by GIS.

In addition you can consult the book Datums and Map Projections for remote sensing, GIS and surveying (Jonathan Iliffe 2000).

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