OPEN GIS

WE DEVELOP PORTAL FOR UPLOADING MAPS USING UMN MAPSERVER. WE ALSO WORK ON PROJECTS USING OPEN GIS. WE USE WEB MAP SERVICE, WEB FEATURE SERVICE AND WEB COVERAGE SERVICE FOR SUCH PROJECTS. A BASIC IDEA OF WMS, WFS AND WCS IS AS GIVEN BELOW:

Web Map Service (WMS) operations can be invoked using a standard web browser by submitting requests in the form of Uniform Resource Locators . The content of such URLs depends on which operation is requested. In particular, when requesting a map the URL indicates what information is to be shown on the map, what portion of the earth is to be mapped, the desired coordinate reference system, and the output image width and height. When two or more maps are produced with the same geographic parameters and output size, the results can be accurately overlaid to produce a composite map.

The OpenGIS Web Feature Service (WFS) is an interface allowing requests for geographical features across the web using platform-independent calls. Geographical features can be thought of as the 'source code' behind a map, where as the WMS interface or online mapping portals return only an image, which can not be edited or spatially analyzed. The XML based GML is the default payload encoding for transporting the geographic features, but other formats like shapefiles can also be used for transport. The WFS specification defines interfaces for describing data manipulation operations of geographic features. Data manipulation operations include the ability to:

    • Create a new feature instance
    • Delete a feature instance
    • Update a feature instance
    • Get or Query features based on spatial and non-spatial constraints

The Web Coverage Service (WCS)  is an Open Geospatial Consortium standard web service for exchanging geospatial data. WCS provides available data together with their detailed descriptions; allows complex queries against these data; and returns data with its original semantics (instead of pictures) which can be interpreted, extrapolated, etc. -- and not just portrayed. This is in contrast to a WFS, which returns actual vector data, and a WMS which produces a digital image file.