Standard (ISO 19128) of the OGC (Open Geoespatial Consortium).
It produces spatial data maps, in a dynamic manner, from the spatial information stored in the Gipuzkoa Spatial Data
Infrastructure. This standard defines the map as a representation of the geographical information in a standard image format (PNG, GIF, JPEG, etc.).
The link to the Gipuzkoa SDI
WMS
is:
http://b5m.gipuzkoa.net/ogc/wms/gipuzkoa_wms?service=wms&request=getcapabilities
The WMS service defines three operations invoked by means of petitions in
URL (Uniform Resource Locator) form:
- 1. GetCapabilities: this provides, in
XML
format, metadata on the spatial objects to serve.
- 2. GetMap: this provides a geographically-referenced map in the form of a digital image.
- 3. GetFeatureInfo: this provides information on the particular characteristics shown in the map.
An example of a GetMap-type petition for the Web Map Service of the Gipuzkoa Spatial Data Infrastructure is:
http://b5m.gipuzkoa.net/ogc/wms/gipuzkoa_wms?service=wms&version=1.3.0&request=getmap&layers=udal_barrutiak_limites_municipales
&styles=&crs=epsg:23030&bbox=530000,4740000,610000,4820000
&width=600&height=600&format=image/png
Here the parameters are:
- styles: styles of visualisation (not yet supported).
- crs: spatial reference system to which the map is to be projected; it is in EPSG Geodetic Parameter Dataset format.
- bbox: corners of the window in the units defined in the previous section.
- width: width in pixels of the picture to be served.
- height: height in pixels of the picture to be served.
- format: outcoming format of the picture.
An example of a GetFeatureInfo-type petition for the Web Map Service of the Gipuzkoa Spatial Data
Infrastructure is:
http://b5m.gipuzkoa.net/ogc/wms/gipuzkoa_wms?service=wms&version=1.3.0&request=getfeatureinfo&layers=udal_barrutiak_limites_municipales&query_layers=udal_barrutiak_limites_municipales&info_format=text/html&crs=epsg:23030&bbox=519966,4740000,612114,4820000&width=1024&height=889&x=495&y=390
Here the parameters are:
- service: type of service required.
- version: version of the Web Map Service (defined in the GetCapabilities petition).
- request: type of petition.
- layers: layer or layers implied in the information request (separated by commas).
- query_layers: same as in the previous section (it is necessary to repeat the same information as in layers).
- info_format: outcoming format of the request (this can be application/vnd.ogc, gml, MIME, or text/html).
- x: the X coordinate of the element in pixels (measured from the upper left hand corner = 0).
- y: the Y coordinate of the element in pixels (measured from the upper left hand corner = 0).
For more information, see:
http://www.opengeospatial.org/
http://en.wikipedia.org/wiki/Web_Map_Service
http://www.epsg.org/
