# Geo-data Services

Geo-data service provides access to a geo-database by local area network (LAN) or the internet using ArcGIS server or open-source GIS servers, i.e., geo server to view, search and queries into database. Open Geospatial Consortium (OGC) regulates rules and standards for geo-data services. So called “OGC services” are listed in this chapter. They are widely accepted and applied by geo-data providers and users. Requirements, types and structure of services are defined in EN ISOS 19119:2016 and ISO 19133:2007 (data types, operations and implementation).

# Overview of existing standards

All OGC standards on web services (OWS) and supporting documents are available to the public at no cost, e.g.:

# WMS (Web Map Service)

WMS offer geo-registered map images in different format (e.g. JPEG, PNG) from distributed geo-database system through GIS servers. It is basically a HTTP/HTTPS link, which provides different request types, two of which are required by any WMS server: GetCapabilities and GetMap, defines a certain geographic location and layer(s) to be managed. Request types that WMS optionally support include: GetFeatureInfo, DescribeLayer and GetLegendGraphic (OpenGeoSpatial). Rules and applications of WMS are provided by EN ISO 19128:2008.

# WFS (Web Feature Service)

WFS allow any usage that might work with web services to get geographic features from one or more distributed spatial information system or a map itself. Similar to WMS (mapping output as an image), WFS deal with create, update, delete and query functions of feature instances from regarding database. WFS serve eight general operations: Capabilities, DescribeFeatureType, DescribeFilterModel, Feature, FeatureWithLock, Property, LockFeature and Transaction. Rules and applications of WFS are provided by EN ISO 19142:2010.

# WCAS (Web Catalogue Service)

# Also known as: CSW, Catalogue Services for the Web

CSW service provides options to publish and searching capabilities of metadata about geospatial data, services, and related information objects. Request types that CSW services offers include: GetCapabilities, DescribeByRecord, GetRecords, GetRecordById, GetDomain, Harvest and Transaction. Requests can encode the parameters in three different ways: GET with URL parameters, POST with form-encoded payload and POST with XML payload.

# WCS (Web Coverage Service)

WCS returns the original data with its descriptions along with actual semantics. This service allows access into coverage data for client-side rendering. WCS also offers clients to get information of a certain portions based on constraints and certain criteria, similar to WFS and WMS service.

# WMTS (Web Map Tile Service)

WMTS makes detailed rendering of a raster data or a large volume of vector data in tiles which supports Key-Value-Pair (KV, process oriented) encoding interfaces, REST (Representational state transfer) encoding and SOAP encoding.

# TJS (Table Joining Service)

The TJS standard joins attribute data with its associated geospatial framework. Attribute data can be stored in one network and mapped with geographic data into another network which contains geometries for the attribute data. TJS provides simple web-based services for searching, accessing and using attribute data from different sources which can generate database, perform analysis and populate maps.

# WMC (Web Map Context)

The OGC XML file standard WMC describes meta-information of a WMS (e.g. the URL, different layers within the service, bounding box rectangle, coordinate system) in XML file, stores and loads XML schema which belongs to it.

# WPS (Web Processing Service)

WPS service defines how to implement a geoprocessing service, geographic calculations or models as a service. It offers simple web-based standardized method of finding, accessing and using of geoprocessing services, at the same time also direct requests and responses of those services. WPS uses HTTP GET, HTTP POST, SOAP and XML as a mechanism for describing the data and for interoperability.