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Free and Open Source Web Mapping Prof. Maria Antonia Brovelli, Dr. Eng. Giorgio Zamboni Politecnico di Milano – Como Campus – Italy Geospatial Web 2 Users INTERNET Data Processes Catalogues Web Mapping 3 Web Map and Geodata Servers Web Map and Geodata Clients INTERNET Map mashing-up 4 Servers Clients INTERNE T Interoperability / Standardization 5 • Open and interoperable components • Interchangeable data • De jure standard: technical instruction set by national and/or international standardization organizations (ISO/OGC/National standards) • De facto standard: technical instruction used by a noteworthy number of people and/or organizations. OGC Web Service (OWS) 6 • XML (eXtensible Markup Language) is used for the definition and the description of applications. The communication is based (in the majority of cases) on the HTTP protocol. Because of using XML, Web Services are platform and OS-independent. • The functioning of OWS (OGC Web Services) can be described in four steps : • the client contacts the server and queries it about its functionalities • the server sends back to the client an XML document containing the functionalities of the supported service • the client asks the server for data • the server provides the data as requested WMS Example 7 Client Server getCapabilities XML Service Metadata C B Map A A MapMap B B getMap Map C Map OGC Web Map and Geodata Services 8 • Data Delivery: • WMS : service that generates maps and makes them available as images or as a series of graphical elements • WFS : service that generates geographic entities or features . If the service is “transaction” (WFS-T), data manipulation is allowed • WCS : service that generates geospatial coverages, that are geospatial information representing space-varying phenomena (fields) OGC Web Map and Geodata Services 9 • Data formats: • SFS : Simple Feature Standard • GML : Geography Markup Language • KML : Keyhole Markup Language • Data search: • CSW : Catalogue Service • WFS-G: Gazetteer Service • Other: • WPS : Web Processing Service • CTS : Coordinate Transformation Service • WTS : Web Terrain Service • SLD : Styled Layer Descriptor • WMC : Web Map Context FOSS Web Map - Geodata Servers (1) 10 Birth: mid ‘90 2001 License: MIT GPL Web: www.mapserver.org www.geoserver.org OGC: WMS, WFS(-T), WCS, WMS, WFS(-T), WCS, GML, SLD, WMC GML, KML, SLD Language: C Java Operating Windows, Linux, Platform System: MacOSX independent FOSS Web Map - Geodata Servers (2) 11 Birth: 2004 2005 License: LGPL LGPL Web: www.mapguide.osgeo.org wiki.deegree.org OGC: WMS, WFS WMS, WFS(-T), WCS, GML, CSW, WFS-G, WPS, WTS, SLD, WMC Language: C++ Java Operating Windows, Linux Platform System: independent Web Map and Geodata Clients (1) 12 • They are interactive viewers in the most of cases simply running in a web browser (Mozilla Firefox, Opera, Internet Explorer, etc.). Sometimes, depending on the technology adopted, plug-ins, i.e. pieces of software providing specific functionalities not available in the simple browser interaction, are requested. • New generation web map and geodata clients are completely independent from the server application that lies behind them : they communicate indifferently by means of OGC open protocols with MapServer, GeoServer, MapGuide, deegree, etc. • By means of this kind of applications, which renders maps from Web Map and Geodata Services, users can navigate maps, zoom in, zoom out, pan, click and query, turn layers on and off or add more maps. They can additionally edit map features (if data are served by a Transactional Web Feature Service), build their own maps, contacting different services on different machines and save them to be used at any time or to be shared. 13 An example 13 Scale Main map Legenda Reference map Scalebar Different languages 14 An example 14 ZoomZoom to Selected fullForward extentBack IdentifyToolSelect Tip Zoom in/out Add ZoomPointZoomRefresh Pan ofoutMeasure inInterest Map 15 An example 15 Data stored in the WMSWFSlocal serverServicesServices (e.g.: shapefiles, rasters, MapInfo tables and all the other formats supported by MapServer) 16 An example 16 Searching tools: Searchitem Identify Select Tool Tip : Web Map and Geodata Clients (2) 17 Web mapping client comparison (German Carrillo, 2010 ) Web Map and Geodata Clients (3) 18 • Previous products are nicely presented for comparison in “Web mapping client comparison v.4” by German Carrillo (may 2010) (*) • The comparison is divided in three parts: • general description: license, origin country, origin company or entity, documentation (languages, formats, level [users, developers]), OSGeo support, comments ; • technical features: source code language, API language, OGC services supported, support of tile-based maps, need of proprietary plug-ins, inclusion of metadata component, mailing lists; • links of interest: screenshot, current version, official website, documentation, features/roadmap, gallery/demo. (*) http://geotux.tuxfamily.org/index.php?option=com_myblog&task=view&id=257&Itemid=59&lang=en Desktop Map and Geodata Clients (1) 19 GRASS Quantum GIS Birth: 1982 2002 License: GPL GPL Web: grass.osgeo.org www.qgis.org OGC: WMS, WFS, GML, WMS, WFS(-T), SFS, WPS GML, KML Language: CC Operating Windows, Linux, Windows, Linux, System: MacOSX MacOSX Desktop Map and Geodata Clients (2) 20 gvSIG OpenJump Birth: 2003 2002 License: GPL GPL Web: www.gvsig.org www.openjump.org OGC: WMS, WFS(-G), WMS, WFS(-T), SFS, WCS, GML, KML, GML, WPS, SLD CSW, SLD Language: Java Java Operating Platform Platform System: independent independent Desktop Map and Geodata Clients (3) 21 uDig MapWindow Birth: 2004 2004 License: Mozilla LGPL Web: www.mapwindow.org udig.refractions.net OGC: WMS, WFS WMS, WFS(-T), SFS, GML, WPS, SLD Language: C#, C++, Visual Basic, Java .NET Operating MS Windows Platform System: independent Multi-D Map and Geodata Clients (1) 22 • Currently the most of the Internet viewers are bi-dimensional (horizontal). • Virtual globe: a 3D representation of the Earth Advantages: • more immersive effects • intuitive interactions • ability to freely move around in the virtual environment by changing the viewing angle and location • capability of representing many different views on the surface of the Earth Multi-D Map and Geodata Clients (2) 23 NASA World Marble QGIS 3D Wind Java SDK OssimPlanet Earth3D deegree 3D Norkart Virtual osgEarth gvSIG 3D Globe Comparison of Open Source Virtual Globes presented at FOSS4G-2010 Barcelona by Mathias Walker, Pirmin Kalberer (http://2010.foss4g.org/presentations/3690.pdf) NASA World Wind (Java SDK) 24 • SDK (Software Development Kit) • Virtual Globe • NASA Open Source Agreement License • Multi -Platform ( Java: “Write Once, Run AnyWhere” ) • JOGL (Java OpenGL 3D - Engine) • Client – WMS Server (v0.6 nightly builds) • Web: worldwind.arc.nasa.gov/java WWJ SDK Architecture (1) 25 Main interfaces: • Globe: represents the planet's shape and terrain (ellipsoid and terrain) • Layer: overlaps geospatial information to the Globe (images, icons, markers, 3D objects, ) • Model: combines the Globe and Layers • SceneController: controls the rendering of the Model • View: controls the user's view of the Model (location – camera settings, ) WWJ SDK Architecture (2) 26 Application Window Environment (Swing, AWT, etc.) WorldWindow Scene Controller Notifier (Global) Configuration (Global) View Frame Controller Canvas Model Globe Layer Web Tessellator Cache WWJ SDK Architecture (3) 27 • Servers NASA – USGS ( U.S. Geological Survey ): • DTM: • SRTM30Plus (30 arc-sec ~900m), SRTM3 v2 v4.1 (3 arc-sec, ~90m), ASTER (~30m), USGS NED (~30m, ~10m US only) • IMAGERY: • BlueMarble (BMNG 1Km), i3-Landsat (15m), USGS Ortho-Topo (1m US only), Urban Area Ortho (0.5 – 0.25m selected US city) WWJ SDK Architecture (4) 28 • Microsoft has allowed World Wind to incorporate Virtual Earth high resolution data for non- commercial use. • It is possible to take from a whichever OGC compliant WMS server the geo-referenced images (and maps) we want to project on the globe . • It is possible to take from specific WMSs, whose code is made available by NASA, the digital elevation models we want to superimpose to the geoid model implemented within the platform. Construction of the scenario 3½D Model (1) 29 • Projection on the Earth surface (2 ½D) of time varying thematic maps THEMATIC IMAGERY MAPS (2D) WMS 2½D WMS SERVER SERVER Remote Remote WWJ -CLIENT Database 3½D Database Model WMS SERVER Map Map Map (WWJ0.6) t=t 0 t=t 1 t=t 2 Scenario DTM WWJ SDK time Remote Database 3½D Model (2) 30 CustomOriginalCustom orthophoto dataset orthophotoCustom –+ orthophoto (Landsati7DTM + thematical + thematical + SRTM) map map 3½D Model (3) 31 Thematical map: t = t 01234 4D Model Irregular shapes (1) 32 E DB Attributes D (mdb, xml, ) C A B SHP FILE SHP Geometry Natural domain (lake) WWJ -CLIENT Loader Builder 3D Thematical Maps E C B D A DB Attributes SHP FILE (mdb, xml, ) Artificial domain (building) 4D Model Irregular shapes (2) 33 A t0 t1 t2 t3 tN t Feature attributes 3D Thematical Maps A(t 0) A(t 1) A(t 2) A(t 3) A() A(t N) 4D Model Irregular shapes (3) 34 3D MODEL (SHP) IMAGERY WEB 3D WMS SERVER SERVER ATTRIBUTES (DB) Remote WWJ-CLIENT Database Remote 4D Database Model WMS SERVER Attribute Attribute Attribute t=t t=t t=t 0 1 2 Scenario DTM Remote WWJ SDK Database time 4D Model Irregular shapes (4) 35 Attribute:Attribute:Mean Incentive Energy Incentive Olbia– Thematized– Classification –Buildings Thematized by Color by by Color Colorand Height Doxel Model (1) 36 3D VARIABLES Geometry NetCDF