Standards for Web dissemination
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Standard web services for accessing geo-spatial data
This section provides a tabular overview of standards required for accessing geo-spatial datasets through the internet. Services provide users (and applications) to access geo-spatial data in a variety of formats ranging from a JPEG map image to a GeoJSON file containing the geometry and attribute data. The services described provide a standard interface that can be deployed in various geo-spatial applications, as well as in spatial data infrastructures (SDIs). The standard interface allows the services to be interchangeable and chained to create more sophisticated services. The services outlined in this section are only some of the basic and well-known geo-spatial services used for accessing geo-spatial data.
Services (ISO 19119:2005)
| Full name | ISO 19119:2005, Geographic information – Services |
| Version | Edition 1 |
| Amendments | Amendment 1 |
| Corrigenda | None |
| Published by | ISO/TC 211 |
| Languages | English, French |
| Online overview | https://www.iso.org/obp/ui/#iso:std:iso:19119:ed-1:v1:en:1 |
| Type of standard | ISO International Standard Meta level |
| Related standard(s) | ISO 19128:2005, Geographic information – Web Map Server interface ISO 19142:2010, Geographic information – Web Feature Service |
| Application | ISO 19119 is a high-level standard that describes service architectural patterns, presents a taxonomy for geographic services, and provides guidelines for the selection of services. OGC Web Service Common Implementation Specification is a similar standard. |
| Conformance classes | Service architecture test module Service specification test module |
| Implementation benefits | The taxonomy provides standard terms that can be used to describe services in a standard way. ISO 19119 provides details on chaining patterns that assist developers when implementing a service chain. Furthermore, the standard defines the basic concepts required when developing or implementing services to ensure integration and interoperability of the services. |
| Products | Standards such as Web Map Server and Web Feature Service are based on the concepts described in ISO 19119. |
Web Map Server interface (ISO 19128:2005)
| Full name | ISO 19128:2005, Geographic information – Web Map Server interface (also published as OpenGIS Web Map Service Implementation Specification) |
| Version | ISO: Edition 1 OGC: V1.3.0 |
| Amendments | None |
| Corrigenda | None |
| Published by | ISO/TC 211 and OGC |
| Languages | English, French |
| Online overview | https://www.iso.org/obp/ui/#iso:std:iso:19128:ed-1:v1:en |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19119:2005, Geographic information – Services ISO 19142:2010, Geographic information – Web Feature Service OpenGIS Catalogue Services Specification |
| Application | ISO 19128 describes the interface for a Web Map Server (WMS). WMS allows a client to request a map image, for example, a JPEG file, from a web service. OpenGIS Web Map Tile Service Implementation Specification is a similar standard. |
| Conformance classes | Basic WMS Queryable WMS |
| Implementation benefits | Through implementing a WMS interface, data can be exposed in a standardized way so that any client familiar with the WMS interface can request a map image of available data. The client specifies parameters, such as the data source, bounding box, and symbology, for the map, through the interface. WMS does not generate map elements, such as a legend. The service can be reused by different clients and is more cost effective than developing a custom service. |
| Products | deegree 3.3 is an example of an OGC compliant open source implementation of the WMS interface. GeoServer 2.5.2 is an example of an open source implementation of the WMS interface. These implementations are generally easy to use, and libraries, such as OpenLayers, have integrated support for WMS calls. |
Web Map Tile Service
| Full name | OpenGIS Web Map Tile Service Implementation Standard |
| Version | V1.0.0 |
| Amendments | None |
| Corrigenda | None |
| Published by | OGC |
| Languages | English |
| Online overview | http://www.opengeospatial.org/standards/wmts |
| Type of standard | OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19119:2005, Geographic information – Services ISO 19142:2010, Geographic information – Web Feature Service OpenGIS Catalogue Services Specification |
| Application | The OGC WMTS provides a complementary approach to the Web Map Service (WMS) for tiling maps. WMS focuses on rendering custom maps and is an ideal solution for dynamic data or custom styled maps (combined with the OGC Style Layer Descriptor (SLD) standard). WMTS trades the flexibility of custom map rendering for the scalability possible by serving of static data (base maps) where the bounding box and scales have been constrained to discrete tiles. The fixed set of tiles allows for the implementation of a WMTS service using a web server that simply returns existing files. The fixed set of tiles also enables the use of standard network mechanisms for scalability such as distributed cache systems. |
| Conformance classes | Client test module Server test module |
| Implementation benefits | With WMS (ISO 19128) custom maps can be rendered for dynamic data or custom styled data. OGC WMTS trades the flexibility of custom maps for the scalability possible by serving static data (base maps) more efficiently. The main benefit of using WMTS is that tiles can be rendered server-side and then cached client-side. This reduces waiting time and bandwidth limitations. OGC WMTS is used to accelerate and optimize map image rendering and delivery. |
| Products | GeoWebCache 1.5.3 is one example of an implementation of OGC WMTS. |
Web Feature Service (ISO 19142:2010)
| Full name | ISO 19142:2010, Geographic information – Web Feature Service (also published as OpenGIS Web Feature Service Implementation Specification) |
| Version | ISO: Edition 2 OGC: V2.0.0 |
| Amendments | None |
| Corrigenda | None |
| Published by | ISO/TC 211 and OGC |
| Languages | English, French |
| Online overview | http://www.opengeospatial.org/standards/wfs |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19119:2005, Geographic information – Services ISO 19128:2005, Geographic information – Web Map Server interface OpenGIS Web Map Tile Service Implementation Standard OpenGIS Catalogue Services Specification |
| Application | ISO 19142 describes the interface for a Web Feature Service (WFS). WFS allow a client to access and perform transactions on geographic features independent of the underlying data store. These WFS implementations allow clients to edit geographic features online and store the changes to the underlying data store. |
| Conformance classes | Simple WFS Basic WFS Transactional WFS Locking WFS |
| Implementation benefits | WFS allow a client to retrieve features or values of features (attribute data) from an underlying data store, and also to access the features to modify or delete features. With WFS the data can be stored in any database or as a shapefile on a server, for example, and the same operations can be performed on the data. This allows the user to query and edit data without having to consider the format of the data. |
| Products | deegree 3.3 is an example of an OGC compliant open source implementation of the WFS interface. |
Filter encoding (ISO 19143:2010)
| Full name | ISO 19143:2010, Geographic information – Filter encoding (also published as OpenGIS Filter Encoding 2.0 Encoding Standard) |
| Version | ISO: Edition 1 OGC: V2.0.0 |
| Amendments | None |
| Corrigenda | None |
| Published by | ISO/TC 211 and OGC |
| Languages | English, French |
| Online overview | https://www.iso.org/obp/ui/#iso:std:iso:19143:ed-1:v1:en |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19117:2012, Geographic information -- Portrayal ISO 19119:2005, Geographic information – Services ISO 19128:2005, Geographic information – Web Map Server interface ISO 19142:2010, Geographic information – Web Feature Service OpenGIS Styled Layer Descriptor Profile of the Web Map Service Implementation Specification OpenGIS Symbology Encoding Implementation Specification |
| Application | ISO 19143 describes XML and Key-Value Pairs (KVP) encodings of a system-neutral syntax for expressing projections, selections and sorting clauses, collectively called a query expression. |
| Conformance classes | Query Ad-hoc Query Functions Resource Identification Minimum Standard Filter Standard Filter Minimum Spatial Filter Spatial Filter Minimum Temporal Filter Temporal Filter Version navigation Sorting Extended Operators Minimum XPath Schema Element Function |
| Implementation benefits | Filter Encoding (FE) describes XML and KVP encodings for expressing filters for spatial queries to select a subset of features based on specific attributes. FE is used in conjunction with other standards and thus allows a client to, for example, create a map using a WMS that only shows residential areas. |
| Products | FE is implemented in conjunction with other services, such as WMS or WFS. An open source examples of an implementation of FE is OpenGeo Suite 4.1.1. |
Catalogue Service
| Full name | OpenGIS Catalogue Service Implementation Specification |
| Version | V2.0.2 |
| Amendments | None |
| Corrigenda | None |
| Published by | OGC |
| Languages | English |
| Online overview | http://www.opengeospatial.org/standards/cat |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19115:2003, Geographic information – Metadata ISO 19119:2005, Geographic information – Services ISO 19128:2005, Geographic information – Web Map Server interface ISO 19136:2007, Geographic information -- Geography Markup Language (GML) ISO 19142:2010, Geographic information – Web Feature Service OpenGIS Web Map Tile Service Implementation Standard OpenGIS |
| Application | Catalogue services support the ability to publish and search collections of descriptive information (metadata) for data, services, and related information objects. The OGC Catalogue Services Specification defines the requirements for the interface and bindings to realise these functionalities. This specification includes an HTTP protocol binding, called the Catalogue Services for the Web (CSW). |
| Conformance classes | None specified |
| Implementation benefits | Catalogue services are an important aspect of most spatial data infrastructures (SDI). It allows the client to search and discover data and associated services. The catalogue service relies on metadata of the data and service. |
| Products | The geoportal of an SDI is commonly an example of a catalogue service. A proprietary catalogue service implementation is the Esri Geoportal Server 1.2.5. |
Sensor Observation Service (SOS)
| Full name | OpenGIS Sensor Observation Service Interface Standard |
| Version | V 2.0 |
| Amendments | None |
| Corrigenda | None |
| Published by | OGC |
| Languages | English |
| Online overview | http://www.opengeospatial.org/standards/sos |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19156:2011, Geographic information – Observations and Measurements OGC Sensor Planning Service Implementation Standard Service OGC SensorML: Model and XML Encoding Standard |
| Application | OpenGIS Sensor Observation Service Interface Standard defines a standardized interface for managing and retrieving metadata and observations from heterogeneous sensor systems. |
| Conformance classes | Main Requirements class Transactional Extension Result Handling Extension Enhanced Operations Extension Spatial Filtering Profile Binding Extension |
| Implementation benefits | Sensors are currently the largest contributor of data in the geo-spatial system. The OGC Sensor Observation Service (SOS) allows the aggregation of readings from live, in-situ and remote sensors. OGC SOS provides the client with the capability to discover or bind with individual sensors, sensor platforms, or networked constellations of sensors. |
| Products | An open source implementation of the SOS service interface is available from 52° North, 52N Sensor Observation Service (SOS) 4.0. |
Standards for styling geo-spatial data
This section provides a tabular overview of standards required for styling geo-spatial data on the web. The standards outlined in this section are rarely implemented without one another. Styled layer descriptor (SLD) and symbol encoding (SE) are also mainly implemented with WMS that supports specifying a style for rendering geo-spatial data allow the user more freedom in their design decisions when requesting a map.
Styled Layer Descriptor (SLD)
| Full name | OpenGIS Styled Layer Descriptor Profile of the Web Map Service Implementation Specification |
| Version | V1.1 |
| Amendments | None |
| Corrigenda | None |
| Published by | OGC |
| Languages | English |
| Online overview | http://www.opengeospatial.org/standards/sld |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19117:2012, Geographic information -- Portrayal ISO 19119:2005, Geographic information – Services ISO 19128:2005, Geographic information – Web Map Server interface ISO 19143:2010, Geographic information – Filter encoding OpenGIS Symbology Encoding Implementation Specification |
| Application | SLD is an XML schema that defines the structure of a layer style. SLD defines styles that can be used for publishing raster and vector data available through a WMS. Basically, SLD is what makes the map more colourful and user-friendly and it is responsible for telling the server how to render the map. |
| Conformance classes | Integrated SLD-WMS Component SLD-WMS Feature Portrayal Service Coverage Portrayal Service |
| Implementation benefits | SLD allows users to define their own styles. With SLD users can develop style sheets that can be used for specific maps, such as topographic maps. This provides consistency and is an effective method for generating maps. The SLD style sheets are reusable and interoperable. |
| Products | Commonly, SLD is implemented in conjunction with a WMS. A number of these implementations also provide extensions on the standard SLD. An example of an SLD implementation is GeoServer 2.5.2. |
Symbology Encoding (SE)
| Full name | OpenGIS Symbology Encoding Implementation Specification |
| Version | V1.1.0 |
| Amendments | None |
| Corrigenda | None |
| Published by | OGC |
| Languages | English |
| Online overview | http://www.opengeospatial.org/standards/se |
| Type of standard | ISO International Standard and OpenGIS Implementation Specification Application level |
| Related standard(s) | ISO 19117:2012, Geographic information -- Portrayal ISO 19119:2005, Geographic information – Services ISO 19128:2005, Geographic information – Web Map Server interface ISO 19143:2010, Geographic information – Filter encoding OpenGIS Styled Layer Descriptor Profile of the Web Map Service Implementation Specification |
| Application | The OGC Symbology Encoding (SE) standard has initially been a part of the Styled Layer Descriptor (SLD) 1.0 standard. OGC SE describes the actual syntax for the description of styles. |
| Conformance classes | Basic Schema conformance Basic Feature Styling Functionality Basic Coverage Styling Functionality Full Feature Styling Functionality Full Coverage Styling Functionality |
| Implementation benefits | OGC SE defines a language for specifying the style of a map. This language can be used to portray the output of WMS, WFS and CSW. |
| Products | SE is implemented in conjunction with a SLD. An example of an SE implementation is GeoServer 2.5.2. |