Georeference
Georeference is another term for spatial reference or Geobezug and describes the situation in a reference system. Data and information through a space with respect to basic geodata and geodata. That is, they refer to a position in geographical space, and are georeferenced.
The spatial reference can be direct or indirect.
- From direct spatial reference is used when data is assigned coordinates.
- Indirectly, the spatial reference is when the information does not relate to long-term fixed coordinates.
Direct Spatial Reference
A direct spatial reference occurs when the spatial position of the information on the ground by means of two - or three-dimensional coordinates realized ( geo ) is. An example of direct spatial reference is the unique location of an address due to their geographical coordinates, or the computational mapping of pixels of a digital image ( eg scanned maps or aerial photographs) to real (world) coordinates using ground control points or world file. This mapping allows a GIS to tailor and scale overlay / localization of different pixel images also different scales and origins for evaluation and further processing in a unified coordinate system.
Indirect Spatial Reference
An indirect spatial reference occurs when the information on not well-defined coordinates, such as on an administrative area (country, city), on a road kilometer marker or a house number range, a block page or area of the aggregation of block pages (for B. postcode area ) refers to the so-called small-scale structure of the local statistics. The indirect spatial reference is used mainly in official statistics and the observation space for allocation, aggregation, analysis and visualization of geodata and is based on statistical information systems.
Standards
The use of spatial reference in spatial data can now be made standardized. Serves this purpose for the direct spatial reference the International Standard ISO 19107, together with ISO 19111th
Local spatial reference
The municipal spatial reference system used addresses (with coordinates: basic spatial data with direct spatial reference ) and a hierarchical organization of the urban area of Wohn-/Baublock to the district (so basic spatial data with indirect spatial reference ) for small-scale spatial mapping of existing data.
This can be without the collection of coordinates, the individual data from the administrative registers assign spatially geo data of local statistics, aggregate and evaluate, via the addresses the individual data can be georeferenced.
In official statistics, the data for administrative areas (usually on the NUTS levels, local to municipalities, precincts, etc.) aggregated. Also for the register-based census in 2011 ( census ), a " addresses and buildings register" built as a framework to merge the registry data.