Geografisk databas

In many systems, when a spatial column is defined in a table, it also includes a choice of coordinate system, chosen from a list of available systems that is stored in a lookup table. A spatial query is a special type of database query supported by spatial databases, including geodatabases. Almost all current relational and object-relational database management systems now have spatial extensions, and some GIS software vendors have developed their own spatial extensions to database management systems.

Because all geographic locations must be specified according to a spatial reference system , spatial databases must also allow for the tracking and transformation of coordinate systems.

Stockholm åren 1200 – 2050. – Temporal, geografisk data

The following are a few of the functions built into PostGIS , a free geodatabase which is a PostgreSQL extension the term 'geometry' refers to a point, line, box or other two or three dimensional shape : [ 7 ]. Tools Tools. Characteristics [ edit ]. References [ edit ]. List [ edit ]. Main category: Geographical databases. The core functionality added by a spatial extension to a database is one or more spatial datatypes , which allow for the storage of spatial data as attribute values in a table.

Download as PDF Printable version. Thus, a spatial join between a points layer of cities and a polygon layer of countries could be performed in a spatially-extended SQL statement as:. Att man skiljer på vanliga databaser och geografiska databaser beror på sättet att arbeta med data för att göra analyser.

Geografisk databas över platser över hela världen

Table of free systems especially for spatial data processing [ edit ]. Main category: Spatial database management systems. While typical databases have developed to manage various numeric and character types of data , such databases require additional functionality to process spatial data types efficiently, and developers have often added geometry or feature data types. The Open Geospatial Consortium OGC developed the Simple Features specification first released in [ 1 ] and sets standards for adding spatial functionality to database systems.

The function names for queries differ across geodatabases. Most spatial databases allow the representation of simple geometric objects such as points , lines and polygons. Wikidata item. Several types of operations are specified by the Open Geospatial Consortium standard:. Some spatial databases handle more complex structures such as 3D objects , topological coverages , linear networks, and triangulated irregular networks TINs.

Article Talk. Contents move to sidebar hide. Geographic database or geodatabase is a georeferenced spatial database, used for storing and manipulating geographic data or geodata, i. Some spatial databases also support the storage of raster data. En geografisk databas är en databas som används för att lagra geodata, det vill säga spatiala strukturer och deras inbördes samband. A spatial database is a general-purpose database usually a relational database that has been enhanced to include spatial data that represents objects defined in a geometric space , along with tools for querying and analyzing such data.

Notes [ edit ]. Retrieved The supported geometry types include points, lines, linestrings, curves, and polygons. Ett geografiskt informationssystem (GIS) är ett datorbaserat system för att samla in, lagra, bearbeta, analysera och presentera geografiska data. Spatial index [ edit ]. Read Edit View history.

Kommungränser geodata A geographic information system (GIS) consists of integrated computer hardware and software that store, manage, analyze, edit, output, and visualize geographic data.

Regso scb Geospatial data is typically large, stored in complex data types, and require specialized indexing, querying, processing, and analysis algorithms.

Scb geodata At its most basic level, an ArcGIS geodatabase is a collection of geographic datasets of various types held in a common file system folder, or a multiuser relational database management system such as IBM Db2, Microsoft SQL Server, Oracle, PostgreSQL, or SAP HANA.

The second major functionality extension in a spatial database is the addition of spatial capabilities to the query language e. The queries differ from non-spatial SQL queries in several important ways. Spatial query [ edit ]. The Intersect vector overlay operation a core element of GIS software could be replicated as:. Database optimized for data representing objects in a geometric space. Spatial database management systems [ edit ].

Database systems use indices to quickly look up values by sorting data values in a linear e. A spatial index is used by a spatial database to optimize spatial queries. Instead, spatial databases use a spatial index designed specifically for multi-dimensional ordering. The datatypes in most spatial databases are based on the OGC Simple Features specification for representing geometric primitives. Two of the most important are that they allow for the use of geometry data types such as points, lines and polygons and that these queries consider the spatial relationship between these geometries.