OGC标准介绍 17
目录
I. WCS- 栅格Web服务
· 概述
WCS（OpenGIS® Web Coverage Service）当前版本是1.1.2。WCS标准定义了一些操作，这些操作允许用户访问“Coverage”数据，如卫星影像、数字高程数据等，也就是栅格数据。
· WCS 的操作
WCS包括以下3个操作：
- GetCapabilities（获取服务的元信息）
-
DescribeCoverage（获取Coverage的描述信息）
-
GetCoverage（获取Coverage）
关于服务涉及的基本元素，可以参考前面的章节：《服务涉及的基本元素》。
· GetCapabilities 操作
1. KVP格式请求
GetCapabilities操作需要以下的参数：
参数
是否必须
默认值
SERVICE
是
WCS
REQUEST=GetCapabilities
是
ACCEPTVERSIONS
SECTIONS
UPDATESEQUENCE
ACCEPTFORMATS
以下是一个WCS使用KVP格式的GetCapabilities操作示例：
http://hostname:port/path?
service=WCS&
request=GetCapabilities
2. XML格式请求
以下是一个WCS使用XML格式的GetCapabilities操作示例：
xml version="1.0" encoding="UTF-8"?>
<
GetCapabilities
xmlns
="http://www.opengis.net/wcs/1.1.1"
xmlns
:xsi
="http://www.w3.org/2001/XMLSchema-instance"
xsi
:schemaLocation
="http://www.opengis.net/wcs/1.1.1 ../wcsGetCapabilities.xsd"
service
="WCS"
/>
3. 响应示例
以下是一个WCS的GetCapabilities操作的响应示例：
xml version="1.0" encoding="UTF-8"?>
<
wcs
:Capabilities
xmlns
="http://www.opengis.net/wcs/1.1"
xmlns
:ows
="http://www.opengis.net/ows/1.1"
xmlns
:xsi
="http://www.w3.org/2001/XMLSchema-instance"
xsi
:schemaLocation
="http://www.opengis.net/wcs/1.1 ../wcsDescribeCoverage.xsd http://www.opengis.net/ows/1.1 ../../../ows/1.1.0/owsAll.xsd"
>
<
ows
:ServiceIdentification
>
<
ows
:Title
>
Web Coverage Service ows :Title >
< ows :Abstract > WCS ows :Abstract >
< ows :ServiceType > WCS ows :ServiceType >
< ows :AccessConstraints > NONE ows :AccessConstraints >
ows :ServiceIdentification >
< ows :OperationsMetadata >
< ows :Operation name ="GetCapabilities" >
...
ows :Operation >
< ows :Operation name ="DescribeCoverage" >
...
ows :Operation >
< ows :Operation name ="GetCoverage" >
...
ows :Operation >
< ows :Constraint name ="PostEncoding" >
< ows :AllowedValues >
< ows :Value > XML ows :Value >
ows :AllowedValues >
ows :Constraint >
ows :OperationsMetadata >
< wcs :Contents >
...
wcs :Contents >
wcs :Capabilities >
· DescribeCoverage 操作
1. KVP格式请求
DescribeCoverage操作需要以下的参数：
参数
是否必须
默认值
VERSION
是
1.1.2
SERVICE
是
WCS
REQUEST=DescribeCoverage
是
IDENTIFIERS
是
以下是一个WCS使用KVP格式的DescribeCoverage操作示例：
http://server_address/path/script?
service=WCS &
request=DescribeCoverage&
version=1.1.2 &
identifiers=Cov1,Cov2,Cov3
2. XML格式请求
以下是一个WCS使用XML格式的DescribeCoverage操作示例：
xml version="1.0" encoding="UTF-8"?>
<
DescribeCoverage
xmlns
="http://www.opengis.net/wcs/1.1"
xmlns
:xsi
="http://www.w3.org/2001/XMLSchema-instance"
xsi
:schemaLocation
="http://www.opengis.net/wcs/1.1 ../wcsDescribeCoverage.xsd"
service
="WCS"
version
="1.1.2"
>
<
Identifier
>
Cov1 Identifier >
< Identifier > Cov2 Identifier >
< Identifier > Cov3 Identifier >
DescribeCoverage >
3. 响应示例
以下是一个WCS的DescribeCoverage操作的响应示例：
xml version="1.0" encoding="UTF-8"?>
<
CoverageDescriptions
xmlns
="http://www.opengis.net/wcs/1.1"
xmlns
:ows
="http://www.opengis.net/ows/1.1"
xmlns
:xsi
="http://www.w3.org/2001/XMLSchema-instance"
xsi
:schemaLocation
="http://www.opengis.net/wcs/1.1 ../wcsDescribeCoverage.xsd http://www.opengis.net/ows/1.1 ../../../ows/1.1.0/owsAll.xsd"
>
<
CoverageDescription
>
<
ows
:Title
>
TBD ows :Title >
< ows :Abstract > TBD ows :Abstract >
< Identifier > TBD Identifier >
< Domain >
< SpatialDomain >
< ows :BoundingBox >
< ows :LowerCorner > -30.00 -30.00 ows :LowerCorner >
< ows :UpperCorner > 30.00 30.00 ows :UpperCorner >
ows :BoundingBox >
SpatialDomain >
Domain >
< Range >
< Field >
< ows :Title > TBD ows :Title >
< ows :Abstract > TBD ows :Abstract >
< Identifier > TBD Identifier >
< Definition >
< ows :AnyValue />
Definition >
< InterpolationMethods >
< InterpolationMethod > linear InterpolationMethod >
< Default > cubic Default >
InterpolationMethods >
Field >
Range >
< SupportedCRS > urn:ogc:def:crs:EPSG::XXXX
SupportedCRS >
< SupportedCRS > urn:ogc:def:crs:EPSG::YYYY
SupportedCRS >
< SupportedFormat > text/xml SupportedFormat >
CoverageDescription >
CoverageDescriptions >
