Introduction to OGC

ORNL OGC Services

Introduction to OGC

The Open Geospatial Consortium, Inc (OGC) is an international consortium of 400 companies, government agencies and universities participating in a consensus process to develop publicly available interface standards. OpenGIS® Standards support interoperable solutions that "geo-enable" the Web, wireless and location-based services, and mainstream IT. The standards empower technology developers to make complex spatial information and services accessible and useful with all kinds of applications.

The OGC standards baseline comprises more than 30 standards. OGC standards cover almost all aspects of geospatial information, including representation, management, monitoring, processing, and application. Most of the OGC standards depend on a generalized architecture captured in a set of documents collectively called the Abstract Specification, which describes a basic data model for representing geographic features. Atop the Abstract Specification, members have developed and continue to develop a growing number of specifications, or standards to serve specific needs for interoperable location and geospatial technology, including GIS.

OGC Standards Used by ORNL DAAC include

  • Web Map Service (WMS) v1.1.1  : defines a standard protocol for serving georeferenced map images over the Internet that are generated by a map server using data from a GIS database.
  • Web Coverge Service (WCS) v1.0.0  : defines a standard protocol and operations that enables interoperable access to geospatial "coverages". The term "grid coverages" typically refers to content such as satellite images, digital aerial photos, digital elevation data, and other phenomena represented by values at each measurement point.
  • Keyhole Markup Language (KML) v2.2  : XML-based language schema for expressing geographic annotation and visualization on existing (or future) Web-based, two-dimensional maps and three-dimensional Earth browsers.
  • Styled Layer Descriptor (SLD) v1.0.0  : describes the appearance of map layers. It is capable of describing the rendering of vector and raster data. A typical use of SLDs is to instruct a Web Map Service (WMS) of how to render a specific layer.
  • Well Known Text (WKT) : is a text markup language for representing vector geometry objects on a map, spatial reference systems of spatial objects and transformations between spatial reference systems. The formats are described in the OGC Simple Feature Access  and Coordinate Transformation Service  specifications.

ORNL OGC Services

The visualization and download capacilities provided by SDAT are based on ORNL DAAC OGC services. The ORNL DAAC OGC services were developed on MapServer . The OGC services include Web Coverage Service (WCS) v1.0.0 and Web Map Service (WMS) v1.1.1.

  • Web Coverge Service (WCS)
    • Version: 1.0.0
    • URL: https://webmap.ornl.gov/ogcbroker/wcs?
    • Supported Operations: GetCapabilities, DescribeCoverage, and GetCoverage
    • Supported GetCoverage Parameters:
      • service: WCS
      • request: GetCoverage
      • version: 1.0.0
      • coverage
      • format
      • bbox
      • crs: EPSG Code (e.g. EPSG: 4326)
      • width
      • height
      • resx
      • resy
      • time: ISO-8601 compatible time value (e.g. 2001-02-01T00:00:00)
      • bands: 1, 2, ...
      • interpolation
      • originator: optional and for internal use, it tells where a request is sent from (e.g. originator=SDAT means the request is sent from Spatial Data Access Tool (SDAT)
    • Supported Formats: ArcInfo ASCII Grid, Erdas Imagine, GeoTIFF, netCDF, and NITF
    • Supported Data Types: BYTE, INT16, and FLOAT32
    • Supported Projections: WGS84, Google Projection, Albers Equal Area Conic, etc.
    • Supported Interpolation Methods: Nearest Neighbor, Average, and Bilinear
  • Web Map Service (WMS)
    • Version: 1.1.1
    • URL: https://webmap.ornl.gov/ogcbroker/wms?
    • Supported Operations: GetCapabilities, GetMap, and GetLegendGraphic
    • Supported GetMap Parameters:
      • service: WMS
      • request: GetMap
      • version: 1.1.1
      • layers
      • format
      • bbox
      • srs: EPSG Code (e.g. EPSG: 4326)
      • width
      • height
      • time: ISO-8601 compatible time value (e.g. 2001-02-01T00:00:00)
      • bands: 1, 2, ...
      • transparent: true/false
      • exceptions: format of the response if error happens (e.g. application/vnd.ogc.se_xml, application/vnd.ogc.se_inimage)
      • sld: URL of SLD XML file
      • originator: optional and for internal use, it tells where a request is sent from (e.g. originator=SDAT means the request is sent from Spatial Data Access Tool (SDAT)
    • Supported Formats: PNG, GIF, and JPEG
    • Supported Projections: WGS84, Google Projection, Albers Equal Area Conic, etc.