Geobrain: Products: WCS4DEM

Brief Introduction

What is GeoBrain WCS4DEM?
GeoBrain WCS4DEM is an OGC-compliant Web Coverage Service, which is used to process multi-source DEM data. Currently, Elevations from the Shuttle Radar Topography Mission (SRTM) is archived.
Why do we need WCS for DEM data?
Each single DEM file covered a relevant spatial area, was stored in a fixed format and was rectified to an corresponding projection. But in many applications, the requested area is covered multiple DEM data or just a portion of one DEM file, and the user wants to customize the DEM into another projection or format. Based on this requirement, we (CSISS) developed a WCS to process such requests. The WCS4DEM will execute mosaic, subset, re-projection and re-format operations in the back end.
Who should use WCS4DEM?
If you need DEM data in your application, such as a scientific model or workflow, WCS4DEm may be a good choice. WCS4DEM will accept the requested URL and return the data stream or link address.
How do you use WCS4DEM?
The following parts will address more detailed WCS operation. The GetCapabilities and DescribeCoverage operations will give the user descriptive information on WCS4DEM server and the selected DEM coverage, and the GeoCoverage will be process your request and return the data stream or link address.

GetCapabilities operation

The Get Capabilities Operation allows WCS clients to retrieve service metadata from a WCS server. The response to a GetCapabilities request shall be an XML document containing service metadata about the server, usually including summary information about the data collections from which coverages may be requested.
Currently, multiple coverages were supported by GeoBrain WCS4DEM: SRTM_90m_Global.Other DEMs are no longer supported due to license issue.
URL: http://cube.csiss.gmu.edu/cgi-bin/gbwcs-dem.cgi?service=wcs&version=1.0.0&request=getcapabilities

DescribeCoverage operation

Once a client has obtained summary descriptions of a WCS server's available coverages, it may be able to make simple GetCoverage requests. However, in most cases the client will need to issue a DescribeCoverage request to obtain a full description of one or more coverages available.
URL: http://cube.csiss.gmu.edu/cgi-bin/gbwcs-dem.cgi?service=wcs&version=1.0.0&request=describecoverage&coverage=SRTM_90m_Global

GetCoverage operation

The mandatory GetCoverage operation allows retrieval of subsets of coverages. The user can execute a subset, re-format and re-project requests to the assign coverage.
Take the SRTM at 90m resolution as an example. The request area is (-90.0W, -89.0W), (38.0N, 39.0N). The output format is GeoTIFF and the projection is WGS84 Lat/Lon (EPSG:4326). The corresponding WCS request as follows: http://cube.csiss.gmu.edu/cgi-bin/gbwcs-dem.cgi?service=wcs&version=1.0.0&request=getcoverage&coverage=SRTM_90m_Global&bbox=-90,38,-89,39&crs=epsg:4326&format=image/tiff&store=false&width=300&height=300

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