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Web Coverage Service (WCS)
OKMaps implements WCS specifications 1.0.0 and 1.1.0 using GeoServer 1.7.6. All layers
published by OGI WCS are also available via WMS.
Basic WCS allows retrieval and querying of unfiltered geographic "coverages" (see definition below).
WCS is for those OKMaps users that wish to query and spatially analyze geographic data rather than
just view pre-rendered images of layers.
The Open Geospatial Consortium (OGC) Web Coverage
Service Interface Standard (WCS) enables interoperable access to geospatial coverages across the web. The
term "coverage" refers to any data representation that has multiple values for each attribute type, where
each direct position within the geometric representation of the feature has a single value for each attribute
type. Examples of a coverage include a raster image, a digital elevation model, or polygon overlay.
Coverages are most commonly associated with the raster data model (and not to be confused with the ESRI data
format with the same name).
Each of the topics below presents an overview of different client-side WCS requests. For more
information on WCS in general, see the Web Coverage
Service (WCS) Implementation Standard.
Currently, only a couple of client-side applications support WCS.
Overview and Request Examples
Click each topic to expand/collapse.
The OGC Geographic Markup Language (GML) is an XML encoding of geospatial data for
the storage, transport, processing and transformation of geographic information. The OGC
Web Features Service
(WFS) enables a client to retrieve and update GML encoded geospatial data.
The following are common WFS operations:
-
GetCapabilities
HTTP GET request that provides service metadata in an XML document.
-
DescribeCoverage
Describes the structure of a specified coverage.
-
GetCoverage
Retrieves a coverage instance.
Software Specific Examples
Currently, there are a limited number of client applications that support WCS.
Click each topic to expand/collapse.
ArcGIS Desktop is a suite of
desktop GIS applications designed for geospatial data management, viewing, editing, and
analysis.
To add a WCS layer to ArcGIS, you must first establish a connection with a map server. This can
be done with ArcCatalog or directly within ArcMap.
In ArcCatalog:
- Expand the GIS Servers folder in the catalog tree
- Double click Add WCS Server
- In the URL text box, enter http://ogi.state.ok.us/geoserver/wcs?
- Click the Get Coverages button
- If the connection is successful, click the OK button
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In ArcMap:
- Click the Add Data button
- From the Look in: list, select GIS Servers
If you already added a connection in ArcCatlog, select that connection, otherwise:
- Double-click Add WCS Server
- In the URL text box, enter http://ogi.state.ok.us/geoserver/wcs?
- Click the Get Layers button
- If the connection is successful, click the OK button
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To add a WCS coverage to ArcMap:
- Double-click the WCS server in the GIS Servers list
- Double click the correct Web Coverage Service
- Select the coverages(s) from the list you wish to add
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gvSIG is a free and
open source desktop GIS designed for managing geographic data. gvSIG supports numerous vector
and raster spatial data formats and can consume standard geospatial web services, such as
WMS, WFS, and WCS.
In gvSIG:
- Open a View
- (Recommended) change coordinate system from UTM N Zone 30 to GCS WGS 84 (EPSG:4326)--see below
- Select Add Layer from the View drop down menu
- Click the WCS tab
- In the Server text box, enter http://ogi.state.ok.us/geoserver/wcs?
- Click the Connect button
- Click the Next button
Once the connection is established:
- Select the Coverage tab
- Select the coverages(s) you wish to add
- Click the OK button
Note: gvSIG is a Spanish project and the default coordinate system for all new views is
UTM Zone 30 N (EPSG:23030). It is highly recommended you change the View to GCS WGS 84 (EPSG:4326)
or a more appropriate coordinate system for Oklahoma data prior to adding WFS layers from OKMaps.
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