Week 7 - Module 4a - Interoperability Standards. WFS & WCS

Overview ### {.module04a02a}

OGC Web Feature Services (WFS)
- Capabilities and purpose
- Overview of the collection of WFS commands
- Sample WFS requests
OGC Web Coverage Services (WCS)
- Capabilities and purpose
- Overview of the collection of WCS commands
- Sample WCS requests

OGC Web Feature Service (WFS) ## {.module04a02a}

Background ### {.module04a02a}

The documents related to the OGC WFS standard are available from: http://www.opengeospatial.org/standards/wfs and all operation parameter tables presented here are based upon the OpenGIS Web Feature Service 2.0 Interface Standard - Panagiotis (Peter) A. Vretanos, editor - 2010-11-02

From the Version 2.0.0 WFS Scope Section:

This International Standard specifies the behaviour of a service that provides transactions on and access to geographic features in a manner independent of the underlying data store. It specifies discovery operations, query operations, locking operations, transaction operations and operations to manage stored parameterized query expressions.

Discovery operations allow the service to be interrogated to determine its capabilities and to retrieve the application schema that defines the feature types that the service offers.

Query operations allow features or values of feature properties to be retrieved from the underlying data store based upon constraints, defined by the client, on feature properties.

Locking operations allow exclusive access to features for the purpose of modifying or deleting features.

Transaction operations allow features to be created, changed, replaced and deleted from the underlying data store.

Stored query operations allow clients to create, drop, list and described parameterized query expressions that are stored by the server and can be repeatedly invoked using different parameter values.

WFS Requests/Operations ### {.module04a02a}

These request types are submitted as part of the required REQUEST key in a KVP HTTP GET request.

GetCapabilities : service metadata (XML) that documents the types of features supported by the service and the operations supported by each feature type

DescribeFeatureType : metadata (XML) that describes the structure of supported feature types

GetPropertyValue : a request for the value(s) of a specified property for a specified featuretype

GetFeature (GetFeatureWithLock) : a request for actual features (XML, or other formats) from the service. The request may include both spatial and non-spatial query constraints

LockFeature : Feature locking operation

Transaction : a request to a WFS that may create, update, or delete features

CreateStoredQuery : a request to create a named WFS query that is stored on the server for future reuse

DropStoredQuery : a request to remove a named WFS query that has previously been stored on the server

ListStoredQueries : a request to retrieve a list of named WFS queries that have been stored on the server

DescribeStoredQueries : a request for more detailed information about specific named WFS queries that are stored on the server

WFS Conformance Levels ### {.module04a02a}

WFS 2.0.0 Requests and their corresponding WFS Compliance Levels

Operation (`REQUEST=`)	V 1.1.0	V 2.0.0	Simple	Basic	Transactional	Locking
`GetCapabilities`
`DescribeFeatureType`
`ListStoredQueries`
`DescribeStoredQueries`
`GetFeature`
`StoredQuery`
`GetPropertyValue`
`Transaction`
`GetFeatureWithLock`
`LockFeature`
`GetGMLObject`

Request Composition ### {.module04a02a}

Requests submitted to a WFS may be submitted either via

HTTP GET : a request that includes all request parameters within the URL submitted to the service. Request parameters are included in the URL as “key=value” pairs (KVPs)

HTTP POST : a request where the URL consists of only the Host and path, with all other request parameters included in the body of the POST document submitted to the service. The request parameters supplied to the server are encoded as XML within the POST document.

SOAP : a request submitted as an encapsulated message within a SOAP transaction.

Servers implementing WFS may support either the HTTP GET, POST, or SOAP request model

Conceptually FeatureType = Layer

KVP for Base WFS Requests ### {.module04a02a}

Base request parameters for all HTTP GET KVP requests

VERSION is required for all operations except the GetCapabilities request

Sample GetCapabilities Requests ### {.module04a02a}

Sample request to USGS Framework Layer (Governmental Units) WFS Service advertised by the USGS TNM Access API page service list - Live Link

http://services.nationalmap.gov/arcgis/services/WFS/govunits/MapServer/WFSServer?
	request=GetCapabilities&
	service=WFS

Sample request to NM RGIS (NM 2010 Census Block Groups) - Live Link

http://gstore.unm.edu/apps/rgis/datasets/715663ba-c1c3-414c-84a7-c671526f8316/services/ogc/wfs?
	SERVICE=wfs&
	REQUEST=GetCapabilities&
	VERSION=1.0.0

KVP for DescribeFeatureType Request ### {.module04a02a}

DescribeFeatureType HTTP GET KVP request

Sample DescribeFeatureType Requests ### {.module04a02a}

USGS Framework Layer (Governmental Units) WFS Service linked from the USGS TNM Access API page service list - Live Link

http://services.nationalmap.gov/arcgis/services/WFS/govunits/MapServer/WFSServer?
	version=1.1.0&
	request=DescribeFeatureType&
	service=WFS&
	typeName=WFS_govunits:State_or_Territory_High-res

Sample request to NM RGIS (NM 2010 Census Block Groups) - Live Link

http://gstore.unm.edu/apps/rgis/datasets/715663ba-c1c3-414c-84a7-c671526f8316/services/ogc/wfs?
	VERSION=1.0.0&
	SERVICE=wfs&
	REQUEST=DescribeFeatureType&
	TYPENAME=tl_2010_35_bg10

KVP for GetFeature Request ### {.module04a02a}

GetFeature HTTP GET KVP request

\

KVP for GetFeature Request - Presentation Parameters ### {.module04a02a}

\

KVP for GetFeature Request - Resolve Parameters### {.module04a02a}

\

KVP for GetFeature Request - Ad-hoc Query Parameters (Figure ) ### {.module04a02a}

\

KVP for GetFeature Request - Stored Query Parameters (Figure )### {.module04a02a}

\

Sample GetFeature Requests ### {.module04a02a}

USGS Framework Layer (Governmental Units) WFS Service linked from the USGS TNM Access API page service list - Live Link

Note: TYPENAME for VERSION=1.1.0 instead of TYPENAMES for VERSION=2.0.0

http://services.nationalmap.gov/arcgis/services/WFS/govunits/MapServer/WFSServer?
	VERSION=1.1.0&
	REQUEST=GetFeature&
	SERVICE=WFS&
	TYPENAME=WFS_govunits:State_or_Territory_High-res

Alternative request (Live Link) that includes an OUTPUTFORMAT parameter

http://services.nationalmap.gov/arcgis/services/WFS/govunits/MapServer/WFSServer?
	VERSION=1.1.0&
	REQUEST=GetFeature&
	SERVICE=WFS&
	TYPENAME=WFS_govunits:State_or_Territory_High-res&
	OUTPUTFORMAT=text/xml;%20subType=gml/3.1.1/profiles/gmlsf/1.0.0/0

OGC Web Coverage Services ## {.module04a02a}

Background ### {.module04a02a}

The documents related to the OGC WCS standard are available from: [http://www.opengeospatial.org/standards/wcs][wcs] with the sample parameters in the following slides based upon the OGC Web Coverage Service 2.0 Interface Standard - KVP Protocol Binding Extension - Peter Baumann, editor - 2010-10-27

From the OGC WCS 2.0 Introduction

The OGC Web Coverage Service (WCS) supports electronic retrieval of geospatial data as "coverages" – that is, digital geospatial information representing space/time-varying phenomena.

This document specifies the WCS core; every implementation of a WCS shall adhere to this standard. This standard thus defines only basic requirements. Extensions to the core will define extensions to meet additional requirements, such as the response encoding. Indeed, additional extensions are required in order to completely specify a WCS for implementation.

A WCS provides access to coverage data in forms that are useful for client-side rendering, as input into scientific models, and for other clients. The WCS may be compared to the OGC Web Feature Service (WFS) and the Web Map Service (WMS). As WMS and WFS service instances, a WCS allows clients to choose portions of a server's information holdings based on spatial constraints and other query criteria.

WCS Requests/Operations ### {.module04a02a}

GetCapabilities : service metadata (XML) that documents the service, including brief information about the data coverages available from the service

DescribeCoverage : a request for more detailed metadata (XML) for one or more coverages listed in the output of the GetCapabilities request

GetCoverage : a request for an actual data product representing a specified coverage. The specific data formats available for delivery will vary from service to service.

Request Composition ### {.module04a02a}

Requests submitted to a WCS may be submitted either via the following protocols, as defined in the three extensions developed thus far for the core WCS standard.

HTTP GET : a request that includes all request parameters within the URL submitted to the service. Request parameters are included in the URL as “name=value” pairs. Extension Link

HTTP POST : a request where the URL consists of only the Host and path, with all other request parameters included in the body of the POST document submitted to the service. The request parameters supplied to the server are encoded as XML within the POST document. Extension Link

XML/SOAP : a request-response model between the client that conforms with the W3C SOAP web services protocol Extension Link

KVP for Base WCS Requests ### {.module04a02a}

Name	Mandatory/Optional	Definition	Data Type
service	M	Identifier of the OGC service	`String`, fixed to "WCS"
request	M	Request type name	`String`, set to operation name
version	M (except for GetCapabilities)	Request protocol version	`String`

Sample WCS `GetCapabilities` requests ### {.module04a02a}

NOAA Global Forecast System THREDDS catalog. Live Link

http://nomads.ncdc.noaa.gov/thredds/wcs/gfs-004/201602/20160228/
	gfs_4_20160228_0000_384.grb2?
	service=WCS&
	version=1.0.0&
	request=GetCapabilities

New Mexico Resource Geographic Information System PRISM Precipitation Normals WCS Service. Live Link

http://gstore.unm.edu/apps/rgis/datasets/2ce10b57-3925-4971-b876-b6fc66d3cca2/services/ogc/wcs?
	SERVICE=wcs&
	REQUEST=GetCapabilities&
	VERSION=1.1.2

KVP for DescribeCoverage Request ### {.module04a02a}

DescribeCoverage HTTP GET KVP request (Figure {@fig:wcsTable01})

{#fig:wcsTable01}

Sample DescribeCoverage Request ### {.module04a02a}

NOAA Global Forecast System THREDDS catalog. Live Link

http://nomads.ncdc.noaa.gov/thredds/wcs/gfs-004/201602/20160228/
gfs_4_20160228_0000_384.grb2?
	service=WCS&
	version=1.0.0&
	request=DescribeCoverage&
	COVERAGE=Categorical_Rain

New Mexico Resource Geographic Information System PRISM Precipitation Normals WCS Service. Live Link

http://gstore.unm.edu/apps/rgis/datasets/2ce10b57-3925-4971-b876-b6fc66d3cca2/services/ogc/wcs?
	SERVICE=wcs&
	REQUEST=DescribeCoverage&
	VERSION=1.1.2&
	COVERAGE=us_ppt_1971_2000_11

KVP for GetCoverage Request ### {.module04a02a}

GetCoverage HTTP GET KVP request (Figure {@fig:wcsTable01})

Subset Definition for GetCoverage Request ### {.module04a02a}

Subset definition for the GetCoverage HTTP GET KVP request

Example from the 2.0 specification:

http://www.myserver.org:port/path?
	service=WCS
	&version=2.0
	&request=GetCoverage
	&coverageId=C0002
	&subset=lon,http://www.opengis.net/def/crs/EPSG/0/4326(-71,47)
	&subset=lat,http://www.opengis.net/def/crs/EPSG/0/4326(-66,51)
	&subset=t,http://www.opengis.net/def/trs/ISO- 8601/0/Gregorian+UTC("2009-11-06T23:20:52Z")

Sample GetCoverage Request ### {.module04a02a}

New Mexico Resource Geographic Information System PRISM Precipitation Normals WCS Service. Live Link

http://gstore.unm.edu/apps/rgis/datasets/2ce10b57-3925-4971-b876-b6fc66d3cca2/services/ogc/wcs?
	SERVICE=wcs&
	REQUEST=GetCoverage&
	VERSION=1.1.2&
	COVERAGE=us_ppt_1971_2000_11&
	CRS=urn:ogc:def:crs:EPSG::4326&
	BBOX=24.0625,-125.02083333333,49.93749998965,-66.47916669008&
	FORMAT=image/tiff&
	WIDTH=2048&
	HEIGHT=905

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lecture07_Mod04_a_02_a.md

lecture07_Mod04_a_02_a.md

Week 7 - Module 4a - Interoperability Standards. WFS & WCS

Overview ### {.module04a02a}

OGC Web Feature Service (WFS) ## {.module04a02a}

Background ### {.module04a02a}

WFS Requests/Operations ### {.module04a02a}

WFS Conformance Levels ### {.module04a02a}

Request Composition ### {.module04a02a}

KVP for Base WFS Requests ### {.module04a02a}

Sample GetCapabilities Requests ### {.module04a02a}

KVP for DescribeFeatureType Request ### {.module04a02a}

Sample DescribeFeatureType Requests ### {.module04a02a}

KVP for GetFeature Request ### {.module04a02a}

KVP for GetFeature Request - Presentation Parameters ### {.module04a02a}

KVP for GetFeature Request - Resolve Parameters### {.module04a02a}

KVP for GetFeature Request - Ad-hoc Query Parameters (Figure ) ### {.module04a02a}

KVP for GetFeature Request - Stored Query Parameters (Figure )### {.module04a02a}

Sample GetFeature Requests ### {.module04a02a}

OGC Web Coverage Services ## {.module04a02a}

Background ### {.module04a02a}

WCS Requests/Operations ### {.module04a02a}

Request Composition ### {.module04a02a}

KVP for Base WCS Requests ### {.module04a02a}

Sample WCS `GetCapabilities` requests ### {.module04a02a}

KVP for DescribeCoverage Request ### {.module04a02a}

Sample DescribeCoverage Request ### {.module04a02a}

KVP for GetCoverage Request ### {.module04a02a}

Subset Definition for GetCoverage Request ### {.module04a02a}

Sample GetCoverage Request ### {.module04a02a}

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Week 7 - Module 4a - Interoperability Standards. WFS & WCS

Overview ### {.module04a02a}

OGC Web Feature Service (WFS) ## {.module04a02a}

Background ### {.module04a02a}

WFS Requests/Operations ### {.module04a02a}

WFS Conformance Levels ### {.module04a02a}

Request Composition ### {.module04a02a}

KVP for Base WFS Requests ### {.module04a02a}

Sample GetCapabilities Requests ### {.module04a02a}

KVP for DescribeFeatureType Request ### {.module04a02a}

Sample DescribeFeatureType Requests ### {.module04a02a}

KVP for GetFeature Request ### {.module04a02a}

KVP for GetFeature Request - Presentation Parameters ### {.module04a02a}

KVP for GetFeature Request - Resolve Parameters### {.module04a02a}

KVP for GetFeature Request - Ad-hoc Query Parameters (Figure ) ### {.module04a02a}

KVP for GetFeature Request - Stored Query Parameters (Figure )### {.module04a02a}

Sample GetFeature Requests ### {.module04a02a}

OGC Web Coverage Services ## {.module04a02a}

Background ### {.module04a02a}

WCS Requests/Operations ### {.module04a02a}

Request Composition ### {.module04a02a}

KVP for Base WCS Requests ### {.module04a02a}

Sample WCS GetCapabilities requests ### {.module04a02a}

KVP for DescribeCoverage Request ### {.module04a02a}

Sample DescribeCoverage Request ### {.module04a02a}

KVP for GetCoverage Request ### {.module04a02a}

Subset Definition for GetCoverage Request ### {.module04a02a}

Sample GetCoverage Request ### {.module04a02a}

Sample WCS `GetCapabilities` requests ### {.module04a02a}