OGC, WMS and WFS

The Vision and the Mission Vision: Realization of the full societal, economic and scientific benefits benefits of integrating electronic location resources into commercial and institutional processes worldwide. Mission: To serve as a global forum for the collaboration of developers and users of spatial data products and services, and to advance the development of international standards for geospatial interoperability.

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Strategic Goals Goal 1 - Provide free and openly available standards to the market, tangible value to Members, and measurable benefits to users. Goal 2 - Lead worldwide in the creation and establishment of standards that allow geospatial content and services to be seamlessly seamlessly integrated into business and civic processes, the spatial web and and enterprise computing. Goal 3 - Facilitate the adoption of open, spatially enabled reference architectures in enterprise environments worldwide. Goal 4 - Advance standards in support of the formation of new and innovative markets and applications for geospatial technologies. Goal 5 - Accelerate market assimilation of interoperability research through collaborative consortium processes.

What is the OGC ? The Open Geospatial Consortium, Consortium, Inc (OGC) International Industry Consortium Industry, government, and university members Over 355 members

Consensus Process to Develop Specifications OpenGIS® OpenGIS® Specifications interoperable solutions that "geo"geo-enable" the Web, wireless and locationlocationbased services, and mainstream IT. The specifications empower technology developers to make complex spatial information and services accessible and useful with all kinds of applications.

OGC collaborates and works closely with: International Organization for Standardization (ISO) World Wide Web Consortium (W3C) OASIS ( Organization for the Advancement of Structured Information Information Standards) And others… others…

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Brief History The OGC was rooted in GRASS and the governing group of GRASS, the OGF ( Open GIS Foundation ) in 1992 The OGC OGC was formed out of this group in 1994, with eight charter members. The first commercial Principal member: Intergraph. The first spec, released in 1997: Simple Features Specification. Number of approved, publicly available OpenGIS Satndard now: 27

Industry Benefits OpenGIS links geographic data with mainstream IT… IT… Standardization is an essential and growing element in the success of the Information Technology industry. The success of the Internet, the the World Wide Web, and ee-Commerce, and are all based on successful Standardization. Most new Information Technology (IT) industry initiatives center around the concept of interoperability, interoperability, and over the last 10 years has become a fundamental goal of IT Standardization. There are no more 'homogeneous islands of computing' which marked marked the late 1980s; today's environment is worldwide and fast paced. The Internet is a formidable promoter of open standards that actually actually work.

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Publicly Available OpenGIS® Standards Catalogue Service Coordinate Transformation Filter Encoding Geographic Objects Geography Markup Language Geospatial eXtensible Access Control Markup Language (GeoXACML (GeoXACML)) GML in JPEG 2000 Grid Coverage Service KML Location Services (OpenLS (OpenLS)) Observations and Measurements Sensor Model Language Sensor Observation Service Sensor Planning Service

Simple Features Simple Features CORBA Simple Features OLE/COM Simple Features SQL Styled Layer Descriptor Symbology Encoding Transducer Markup Language Web Coverage Service Web Feature Service Web Map Context Web Map Service Web Processing Service Web Service Common

WMS & WFS Web Map Service

SLD

Web Feature Service

(WMS)

(WFS) Filter

Save current state Web Map Picture Context (Styled layer) (WMC)

GML Objects Rendering

Picture

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WMS (Web Map Service) Provides images of map data defined by a geographic / spatial component Provides point based query functionality Interoperable means of map compositing from multiple servers

WMS (Web Map Service) HTTP based (GET or POST) Currently version 1.1.1 Operations GetCapabilities GetMap GetFeatureInfo Operation keywords are CaSeCaSe-InSeNsItIvE Opearation values are casecase-sensitive

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WMS (Web Map Service) GetCapabilities Provides XML of service functionality metadata, and layer metadata such as what data layer can be served, format available, SRS projection etc. Parameters Version (version of specification) Service (multiple services may exist from this service, e.g. WMS, WFS, WCS) Request (GetCapabilities (GetCapabilities)) http://127.0.0.1/cgihttp://127.0.0.1/cgibin/mapserv?map=/path/config.map& version=1.1.1& =1.1.1&servic servicee=WMS&requ bin/mapserv?map=/path/config.map&version WMS&requ est= est=GetCapabilities

GetCapabilities (WMS)

Site Title Name

URL Link for WMS

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GetCapabilities (WMS) Image Format available for request

Info format available for request

GetCapabilities (WMS)

Spatial Reference System: Projection/Datum of this webmap

:Bounding of this webmap in Lat/Long :Bounding in define SRS

Layer Name, SRS of layer This layer does not define bounding box, thus extent is equal to entire webmap

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GetCapabilities (WMS)

This layer define its own extent and different map projection from webmap.

WMS (Web Map Service) GetMap Returns generate graphic image of data according to extent, layer etc. of map data Image, not features, not attributes Key parameter LAYERS : data desired to be draw [road,river,sea [road,river,sea,,…] First list item is the most bottom of image map BBOX : extent of image map [minx, miny ,maxx ,maxy ] SRS : reference system/ projection of bounding box http://www.epsg.org http://www.epsg.org)) such epsg:4326 -> Lat/Long (WGS84) FORMAT : image format return from WMS Server

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WMS (Web Map Service) Key parameter (GetMap (GetMap cont) STYLES : (desired portrayal of data) e.g.. layers=elevation,roads,railways&styles =default,red,blue layers=elevation,roads,railways&styles=

Empty list value for non styled layers

REQUEST ( = GetMap) GetMap) VERSION SERVICE WIDTH : width of return image HEIGHT : height of return image

WMS (Web Map Service) Key parameter (GetMap (GetMap cont) TRANSPARENT : Either TRUE or FALSE Useful for layering data from multiple remote WMS services atop eachother for map composition Depends on image format (JPEG is not transparent) Depends on web browser support GIF transparency is supported in all browser but PNG is only Netscape7, etc

BGCOLOR : optional background color of image

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WMS (Web Map Service) http://server=1.1.0& http://server-maps.com/mapserv?map= maps.com/mapserv?map=mapfile.map&VERSION mapfile.map&VERSION=1.1.0& REQUEST= REQUEST=GetMap& GetMap& SRS=EPSG:4326& SRS=EPSG:4326& BBOX= BBOX=-97.105,24.913,78.794,36.358& WIDTH=560& WIDTH=560& HEIGHT=350& HEIGHT=350& LAYERS=WATER,ROAD,POLBNDL& LAYERS=WATER,ROAD,POLBNDL& STYLES=0XFF8080,0X101040,BLACK& STYLES=0XFF8080,0X101040,BLACK& FORMAT=image/ png& & FORMAT=image/png BGCOLOR=0xFFFFFF& BGCOLOR=0xFFFFFF& TRANSPARENT=TRUE& TRANSPARENT=TRUE& SERVICE=WMS& SERVICE=WMS&

Web Map Service

Client’ Client’s GIS data base Field Survey

Bathy map

WMS Service From Multi Servers Request internet Result

User

Seamless: No need to know servers WMS at Other Mapserver Dynamic Link to Server : No Need to Copy Huge Dataset internet

WMS Connection WMS Service Request internet

Tsunami Web Map Server

Result

User Remote Sensing Image

Existing Map Socio Economic Data

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OGC WMS WMS Service

GetMap

Internet

Hurricane Image

a-map-co.com

GetMap User

OGC WMS

Map Image

b-maps.com

Web Map Service (WMS) GetFeatureInfo Asks for information about features display in the map by pointpoint-based queries on map data No ability for complex, expressionexpression-like queries

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Web Map Service (WMS) GetFeatureInfo Parameters Use request=GetFeatureInfo request=GetFeatureInfo instead of GetMap Pass on ALL GetMap keywordkeyword-value pairs as if performing a GetMap request x (pixel value in X image coordinates) y (pixel value in Y image coordinates) query_layers (layers to be queried) Can be one or multiple layers This does not substitute passing the layers parameter

Web Map Service (WMS) GetFeatureInfo Info_fomat HTML : Difficult for parser GML.1 :XML:XML-Based Lack of common definition structure between vendor implementation

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WFS (Web Feature Service) Feature level access to spatial data (vectors) Rich query interface Returns GML Transactional capability A transaction request is composed of operations that modify features; that is create, update, and delete operations on geographic features.

Security considerations for OGC:WFSOGC:WFS-T A web feature service may be able to process a lock request on one or more instances of a feature type for the duration of a transaction.

WFS (Web Feature Service) Operations GetCapabilities DescribeFeatureType GetFeature

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WFS (Web Feature Service) GetCapabilities Same WMS - > GetCapabilities Parameters VERSION SERVICE REQUEST

WFS (Web Feature Service) DescribeFeatureType Provides an outline of the structure of a feature type (fields, etc.) in XML schema XML schema document must be a valid GML application schema and defines the schema of the feature types listed in the request. Parameters VERSION SERVICE REQUEST TYPENAME

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WFS (Web Feature Service) GetFeature Parameters VERSION SERVICE REQUEST TYPENAME FILTER (optional) BBOX (can also be done through FILTER)

GML - Geography Markup Language

WFS - Web Feature Server • Get Capabilities • Describe Feature Type

XML GML Schema

• Get Features • Lock Feature • Transaction

GML

- Insert - Update - Delete

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Basics of GML Geography Markup Language (GML) is an XML grammar written in XML Schema for the modeling, transport, and storage of geographic information. GML provides a variety of kinds of objects for describing geography including features, coordinate reference systems, geometry, topology, time, units of measure and generalized values. GML includes Geometries and Coordinate Reference System (based on EPSG) A temporal reference system (based on ISO 8601) A Units of Measure (UOM) dictionary

GML - Geography Markup Language

Encoding GML Features Without Geometry XML Feature ID

Smith 42 Smithy Bonehead

GML

A nice old chap Smith 42 Smithy Bonehead 5.040.0 http://www.opengeospatial.org/specs/

More & More OGC : SLD ( Styled Layer Description) “AddAdd-on” on” specification to OGC:WMS Enables custom styling

OGC : Filter “Add on” on” specification to OGC:WFS Custom XML query language such as draw only “Capital City” City” point.

OGC :WMC (WEB MAP CONTEXT) Save Web Mapping Application State Like “save project” project”

OGC : WCS (WEB COVERAGE SERVICE) More Advanced of WMS and WFS Multidimensional : returns representations of spacespace-varying phenomena that relate a spatiospatio-temporal domain to a range of properties.

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More & More OGC Web Site http://www.opengeospatial.org /specs/?page=specs http://www.opengeospatial.org/specs/?page=specs

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