DELIVERY SPATIAL DATA USING WEB SERVICES (WEB MAP SERVICE AND WEB FEATURE SERVICE) BASED ON GEOGRAPHIC INFORMATION SYSTEMS

A.V. Ales Versic

Environmental agency of the Republic of Slovenia

aversic@gov.si

 

Article describes two web services with Geographic Information Systems, which enable exchange of spatial data between distributor (in this case government agency) and their customers, who need environmental spatial data. Environmental Agency of the Republic of Slovenia (EARS) had re-established Web Map and Web Feature service, which enable different users to get environmental spatial data. Environmental Agency of the Republic of Slovenia is the major administrator for environmental spatial data in Slovenia.

In the introduction the reasons for implementing this web services and standards for this topic are described. One of the main reasons to introduce this services was to be prepared to implement INSPIRE directive, to support strategic goals of EARS and to support government in improvements of the administrative information system and opening data bases to the public. For the realisation of these services we used the following standards: OpenGIS Web Map Service (WMS) Implementation Specification, 1.1.1; OpenGIS Web Feature Service (WFS) Implementation Specification 1.0 and OpenGIS Geography Markup Language (GML) Encoding Specification 2.0.

Furthermore are described the differences between web map and web feature service and their technological characteristic.

At the end two solutions, which were established in the Environmental Agency of the Republic of Slovenia, are presented. Web map service (WMS) enables access maps prepared in advance with appropriate symbols; meanwhile web feature service (WFS) enables the access to data in two ways. Users can download on JAVA technology based WFSUIClient to his computer, which then communicate with WFS server. WFSUIClient enables that the user can choose in which format (.shp or .gml) to download the data, choose the projection, which attributes will be added and use some query. Users also have advanced options where they can as before mentioned as well adjust the time of refreshing data. Second option is with WFS protocol, where users use the URL and add to their application.