Simple Features
Simple Features(officiallySimple Feature Access) is a set of standards that specify a common storage and access model ofgeographic featuresmade of mostly two-dimensional geometries (point, line, polygon, multi-point, multi-line, etc.) used bygeographic databasesandgeographic information systems. It is formalized by both theOpen Geospatial Consortium(OGC) and theInternational Organization for Standardization(ISO).
The ISO 19125 standard comes in two parts. Part 1, ISO 19125-1 (SFA-CA for "common architecture" ), defines a model for two-dimensional simple features, with linear interpolation between vertices, defined in a hierarchy ofclasses;this part also definesrepresentation of geometryin text and binary forms. Part 2 of the standard, ISO 19125-2 (SFA-SQL), defines a "SQL/MM"language bindingAPI forSQLunder the prefix "ST_".[1]Theopen accessOGC standards cover additionally APIs forCORBAandOLE/COM,although these have lagged behind the SQL one and are not standardized by ISO. There are also adaptations to other languages covered below.
The ISO/IEC 13249-3SQL/MM Spatialextends the Simple Features data model, originally based onstraight-line segments,addingcircular interpolations(e.g.circular arcs) and other features like coordinate transformations and methods for validating geometries, as well asGeography Markup Languagesupport.[1]
Details
[edit]Part 1
[edit]This sectionneeds expansion.You can help byadding to it.(November 2012) |
The geometries are associated withspatial reference systems.The standard also specifiesattributes,methodsandassertionswith the geometries, in theobject-orientedstyle. In general, a 2D geometry is simple if it contains no self-intersection. The specification definesDE-9IMspatial predicates and several spatial operators that can be used to generate new geometries from existing geometries.
Part 2
[edit]Part 2 is a SQL binding to Part 1, providing a translation of the interface to non-object-oriented environments. For example, instead of asomeGeometryObject.isEmpty()
as in Part 1, SQL/MM uses aST_IsEmpty(...)
function in SQL.
Spatial
[edit]The spatial extension adds the datatypes "Circularstring", "CompoundCurve", "CurvePolygon", "PolyhedralSurface", the last of which is also included into the OGC standard. It also defines the SQL/MM versions of these types and operations on them.
Implementations
[edit]This sectionneeds expansion.You can help byadding to it.(November 2012) |
Direct implementations of Part 2 (SQL/MM) include:
- MySQLSpatial Extensions.[2]Up to MySQL 5.5, all of the functions that calculate relations between geometries are implemented usingbounding boxesnot the actual geometries.[3]Starting from version 5.6, MySQL offers support for precise object shapes.[4]
- MonetDB/GISextension forMonetDB.[5]
- PostGISextension forPostgreSQL,also supporting some of the SQL/MM Spatial features.[6]
- SpatiaLiteextension forSQLite[7]
- Oracle Spatial,which also implements some of the advanced features from SQL/MM Spatial.[8]
- IBM Db2Spatial Extender andIBM InformixSpatial DataBlade.[6]
- Microsoft SQL Serversince version 2008,[6]with significant additions in the 2012 version.[9]
- SAPSybase IQ.[10]
- SAP HANAas of 1.0 SPS6.[11]
Adaptations include:
- Implementations of the CORBA and OLE/COM interfaces detailed above are mainly produced by commercial vendors maintaining legacy technology.
- R:The sf package[12]implements Simple Features and contains functions that bind toGDALfor reading and writing data, to GEOS for geometrical operations, and toPROJfor projection conversions and datum transformations.
- TheGDALlibrary implements the Simple Features data model in its OGR component.[13]
- TheJava-baseddeegreeframework implements SFA (part 1) and various other OGC standards.[14]
- TheRustlibrarygeo_typesimplements geometry primitives that adhere to the simple feature access standards.[15]
GeoSPARQLis anOGCstandard that is intended to allow geospatially-linked datarepresentation and querying based onRDFandSPARQLby defining anontologyfor geospatial reasoning supporting a small Simple Features (as well asDE-9IMandRCC8)RDFS/OWLvocabulary forGMLandWKTliterals.[16]
As of 2012, variousNoSQLdatabases had very limited support for "anything more complex than a bounding box or proximity search".[3]
See also
[edit]References
[edit]- ^abWolfgang Kresse; David M. Danko (2011).Springer Handbook of Geographic Information.Springer. pp.81–83.ISBN978-3-540-72678-4.
- ^"MySQL 5.1 documentation on Spatial extensions".mysql.com.Retrieved2 April2018.
- ^abFrank Hardisty (Fall 2012)."Penn State Geography 583: Geospatial System Analysis and Design. Databases".
- ^"MySQL:: MySQL 5.6 Reference Manual:: 12.15.9 Functions That Test Spatial Relations Between Geometry Objects".dev.mysql.com.Retrieved2 April2018.
- ^"GeoSpatial - MonetDB".4 March 2014.
- ^abcWolfgang Kresse; David M. Danko (2011).Springer Handbook of Geographic Information.Springer. pp.105–106.ISBN978-3-540-72678-4.
- ^"SpatiaLite: SpatiaLite".www.gaia-gis.it.Retrieved2 April2018.
- ^Ravikanth V. Kothuri; Euro Beinat; Albert Godfrind (2004).Pro Oracle Spatial.Apress. p. 65.ISBN978-1-59059-383-7.
- ^Alastair Aitchison (2012).Pro Spatial with SQL Server 2012.Apress. pp. 21–23.ISBN978-1-4302-3491-3.
- ^http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.infocenter.dc01964.1602/doc/html/saiq-standards-compatibility-spatial.htmlSAP Sybase IQ support for spatial data
- ^http://help.sap.com/saphelp_hanaplatform/helpdata/en/7a/2f4266787c1014a9b6ab6cf937f8ac/content.htm?frameset=/en/7a/2d11d7787c1014ac3a8663250814c2/frameset.htm¤t_toc=/en/99/d10e4fdaaf41588480a43478e840d5/plain.htm&node_id=12SAP HANA Spatial Reference: Supported Import and Export Formats for Spatial Data
- ^Pebesma, Edzer; Bivand, Roger; Cook, Ian; Keitt, Tim; Sumner, Michael; Lovelace, Robin; Wickham, Hadley; Ooms, Jeroen; Racine, Etienne (22 March 2018)."sf: Simple Features for R".Retrieved2 April2018– via R-Packages.
- ^"FAQ: What is this OGR stuff?".www.gdal.org.Retrieved2 April2018.
- ^Shashi Shekhar; Hui Xiong (2007).Encyclopedia of GIS.Springer. pp. 235–236.ISBN978-0-387-30858-6.
- ^"geo_types - Rust".docs.rs.Retrieved2023-03-19.
- ^Battle, Robert; Kolas, Dave (2012)."Enabling the Geospatial Semantic Web with Parliament and GeoSPARQL"(PDF).Semantic Web.3(4).IOS Press:355–370.doi:10.3233/SW-2012-0065.Retrieved21 November2012.
External links
[edit]Standard documents
[edit]- ISO/IEC:
- OpenGIS
- OpenGIS Implementation Specification for Geographic information - Simple feature access - Part 1: Common architecture (05-126, 06-103r3, 06-103r4),current version 1.2.1
- OpenGIS Simple Feature Access - Part 2: SQL Option (99-054, 05-134, 06-104r3, 06-104r4),current version 1.2.1, formerly OpenGIS Simple Features [Implementation Specification] for SQL
- OpenGIS Simple Features Implementation Specification for CORBA (99-054),current version 1.0
- OpenGIS Simple Features Implementation Specification for OLE/COM (99-050),current version 1.1