Local versus remote access

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6.3 Coordinate Reference System CRS

The following sections have been extracted from: ฀ https:portal.opengeospatial.orgtwikibinviewOWS8AviationWeatherCrs ฀ OGC Web Coverage Service specification v 2.0 http:www.opengeospatial.orgstandardswcs ฀ WCS Core change request CR https:portal.opengeospatial.orgfiles?artifact_id=44308 ฀ Weather Exchange Information Model WXXM http:www.eurocontrol.intaimpublicstandard_pagemet_wie.html ฀ Encoding Representative Weather Datasets https:portal.opengeospatial.orgfiles?artifact_id=46115

6.3.1 Overview

The Coordinate Reference System CRS Domain Working Group develops strategies for encoding the earth coordinate reference systems and transformations between coordinate reference systems. The group has worked consistently on the joint OGC-ISO Document 19111 - Spatial Referencing by Coordinates. The Aviation Thread of OWS-8 will explore ways to address the following two issues: - How can a WCS client request a specific Coordinate Reference System CRS including projection, projection parameters, datum, etc when there is no existing EPSG or other code associated with the CRS? How can such CRSs be encoded in this case well-known text, GML, etc? - Can a WCS 2.0 server formally advertise the capability to support arbitrary CRSs as opposed to a fixed number of possible CRSs, as specified in the client query? As a background, in the weather domain, the set of projected spaces of interest to clients is potentially infinite. For example, a data set available in a Lambert Conformal projection with a certain projection origin and other parameterizations may be requested by a client in Lambert Azimuthal Equal Area projection with a completely different origin and other parameterization. EPSG codes have been insufficient to describe the combinations of projections and projection parameters that the clients may require. From the WCS server perspective, the requirement becomes that of supporting an infinite number of actual CRSs on-demand, and to be able to advertise such capability in their capabilities statement. Note the focus here is on solutions based on the WCS standard and not on the Web Processing Service WPS, which could also be used to support custom CRS conversions.