Web Coverage Service (WCS)
Unlike WMS, which delivers static map images, WCS provides raw raster data that can be used for detailed analysis in GIS applications.
Web Coverage Service (WCS) is a geographical data format provided by the Open Geospatial Consortium (OGC). WCS is an internet protocol that allows raster data to be requested, manipulated, and retrieved over the internet. The geographic data transported by this service is known as "coverage". Coverage refers to the digital representation of a spatial-temporal phenomenon, which includes satellite images, digital aerial photos, digital elevation models, and other geographically referenced raster data.
The main operation of WCS is GetCoverage which allows the user to retrieve coverage data from a server. This is different from the Web Map Service (WMS) which only provides static images. While WMS gives the user a cartographic representation of data, WCS provides the actual data that is used to make the map. Thus, WCS data can be used for more than just visualization. It can be analyzed and manipulated to derive useful information in GIS applications.
In a WCS request, the user specifies the desired coverage offering and the section of interest. They can also specify the output format desired for the data. The request can further be altered to adjust the interpolation method, the resolution, and the coordinate reference system. The server interprets this request and returns the data in the specified format.
One crucial advantage of WCS data is that it is interoperable. This means that it can be used across different software platforms and applications. This is because WCS adheres to standards set by the OGC, facilitating seamless communication across different GIS systems.
Even more, WCS supports various formats including GeoTIFF, HDF-EOS, and netCDF. GeoTIFF is widely used for its ability to embed georeferencing information directly into a TIFF file, while HDF-EOS is useful for handling large datasets, and netCDF is beneficial for multidimensional data. The choice of format depends on the needs of the user and the capabilities of the server.
In summary, WCS provides an effective way of transporting raw raster data over the web, mainly for analysis and manipulation in GIS applications. The interoperability and wide range of supported formats are key features that contribute to the utility of WCS data. However, it is important to note that the use of WCS requires a robust internet connection, given the potentially large size of the datasets being transferred. If this condition is met, WCS proves to be a valuable tool for any GIS expert or user.
