At the heart of every GIS service is a GIS source: map, database, the geoprocessing tool, etc. GIS service is the link between the source resource and the client application (desktop or mobile GIS, web application, etc.), performing the data transmission from the resource to the client and back, serving the various needs of users. In order to refer to geographic information resource, the client application does not need to understand storage formats of geographic data and functions — all this assumes the GIS service. It is enough to send standard query to the GIS service on the Internet/Intranet to get the desired result. For example, to send the coordinates of the plot area and receive in response a corresponding image.
GIS services can be used in the following ways:
As a part of web-GIS — for realization on web sites the opportunities of access to spatial data and functionality of geoprocessing.
For example, a real estate agency can create a corporate website for their agents, which will display a detailed map of the city, the location offered for sale/lease of real estate with the ability to view detailed information about each object. In this case, the display of the map and information about the objects will be provided by a web mapping service that is published on the GIS server in the organization.
As independent web services — for presenting to other organizations the possibility of introducing the services in your own applications on a paid or free basis.
For example, the Ministry of water resources can create a web map service that contains relevant information about water bodies in the region (boundaries, characteristics, contamination, etc.) and provide other interested state bodies and organizations with the ability to add the service into their own web GIS on a paid or free basis.
The advantages of using GIS services in the web GIS are:
- standardization of the use of geographic information resources in the organization (users work with the same data and functions);
- reduced cost of purchasing desktop GIS applications and organization of local data storage.
The advantages of using GIS services as independent web services are:
- for organizations that have developed GIS service — an opportunity for additional revenue by providing paid access to their GIS services;
- for third-party organizations that use GIS service — the ability to access relevant data in another subject area without the need to independently develop, update and maintain this data.
There are several major types of GIS services differentiated by their functionality.
|Map service||Providing access to the contents of a map, including the ones to individual layers, objects and attributes|
|Image service||Providing access to datasets, including to the pixel values, metadata and channels|
|Geocode service||Search for objects on the map by address, identifying the address of the specified point on the map|
|Geodata service||Providing access to the contents of a geodatabase for querying, retrieval and data replication|
|Network analysis service||Analysis of the transport network (building optimal routes)|
|Geoprocessing||Modeling and analysis of spatial relationships (forecasting the spread of flooding, the analysis of patterns of occurrence of disease outbreaks, etc.)|
For standardization of created GIS services and to ensure access to them from various applications, developers often adhere to the standards of the Open Geospatial Consortium (OGC). The main standards of GIS services are:
- Web Map Service (WMS) — to work with collections of layers as map images;
- Web Map Tile Service (WMTS) — to work with map layers as cached map tiles;
- Web Feature Service (WFS) — to work with the data as vector features;
- Web Coverage Service (WCS) — to work with the data as raster coverages;
- Web Processing Service (WPS) — to provide geoprocessing tools.
ДTo publish and support GIS services, server software (GIS server) is need, for example, ArcGIS for Server of the Esri company
SOVZOND Company offers services for the development of GIS to meet the needs of the customer. Examples of offered GIS services can be found in section Online geoinformation services.