Presentation on theme: "GIS in the Internet - architectures, standards and OpenSource Team SPADE – Spatial Decision Support."— Presentation transcript:
GIS in the Internet - architectures, standards and OpenSource Team SPADE – Spatial Decision Support
GIS in the Internet - architectures, standards and OpenSource Internet GIS-Overview
Seite 3 GIS in the Internet – Comparison to standard GIS Standard GISInternet GIS Data acquisitionYesNo Preparation, processingYesNo Database connectivityYes Analysis and transformationYesNo; Limited Information und queryYes cartographic presentationYes; LimitedNo; Limited integration into available interfaces Yes; LimitedYes Processing of RASTER and vector data Yes Yes; Limited
Seite 4 GIS in the Internet – standard architectures RDBMS Middleware: DBMS-InterfaceInternet GIS GIS-Softwareweb server WAN special application softwareweb-client (Browser) ? LAN ?
Seite 5 Common Restrictions for Internet-GIS: database connectivity: Usually only information queries possible!! Reasons: - data security and security permissions - complete transactions are a complex matter! thin Client: the client usually gets no vector data and therefore theres no client-side data transformation and analysis possible! Reasons: common architecture allows only thin clients und thick GIS-Server Tools = webmapserver OGC (Open GIS Consortium) Specifications GIS in the Internet – standard architectures
Seite 6 GIS in the Internet – standard interfaces and data formats data transmissions through http and ftp protocols! Raster images: gif, JPG/JPEG, PNG Vector graphics: XML based graphic formats: SVG Scalable Vector Graphics (W3C and Adobe), VML Vector Markup Language (Microsoft) (deprecated since 1998), PGML Precision Graphics Markup Language, WebCGM and the OGC-standard: GML (Geography Markup Language) 3-D visualisations: VRML Virtual Reality Markup Language standard interfaces between database and InternetGIS and between webserver and Client: OGC OpenGIS Consortium Specifications
GIS in the Internet - architectures, standards and OpenSource Internet GIS- Some open-source and freeware products
Seite 8 A)UMN MapServer MapServer is an OpenSource development environment for building spatially enabled Internet applications. The MapServer was originally developed by (UMN) ForNet project in cooperation with NASA and the Minnesota DNR Current development is funded by the TerraSIP project, a NASA sponsored project between the UMN and consortium of land management interests. MapServer will run where most commercial systems won't or can't, on Linux/Apache platforms. MapServer is known to compile on most UNIXes and will run under Windows NT/98/95/00.
Seite 9 Web Server A)UMN MapServer: architecture RDMS: Oracle, MySQL... Geodata files:.shp MapScript (Perl, PHP, Java) Cgi -bin.Map file Html/Script/Java WAN Html template http request (URL) Raster image or XML text
Seite 10 A)UMN MapServer: out-of-the-box functions as CGI-program vector formats supported: ESRI shapefiles, simple embedded features, ESRI ArcSDE raster formats supported: TIFF/GeoTIFF, GIF, PNG, ERDAS, JPEG and EPPL7 fully customizable, template driven output (Html Templates) automatic legend and scalebar building; feature labeling including label collision mediation; scale dependent feature drawing thematic map building using logical or regular expression based classes feature selection by item/value, point, area or another feature quadtree spatial indexing for shapefiles support for tiled raster and vector data (display only) on-the-fly configuration via URLs; on-the-fly projection
Seite 12 B)Degree Framework Java framework for the implementation of local and webbased distributed GIS systems Interfaces and formats according to OGC (Open GIS Consortium)-standards: - GML - WMS specification 1.1.1 (official reference implementation!) - WFS Specification 1.0.0 - database transactions possible (so far only for attribute data)!! dynamic integration of distributed data ressources (cascaded WMS, WFS) Runs on Windows and LINUX Developed by the geographical institute of Bonn and lat/lon
Seite 13 B)Degree Framework: architecture Web Server RDMS: Oracle Spatial, JDBC-databases Geodaten files:.shp XML: capabilities WAN Server WFS-servlet XML: capabilities local WFSWMS-servlet XML: capabilities WAN http XML GML http requests
Seite 15 C)OpenSource MapServer: synopsis and advantages Source code is accessable, degree even throuh a CVS server Versions available for free MapServer in comparison to all others is very fast A serverscript interface avialable for PHP and Perl (MapServer) GNU-Licence At the moment OGC Webmapping standards are being integrated: - WMS Server - WFS Server (degree including DB- transactions!!) ->All products support also thick clients !!
Seite 16 General possible architectures for OGC mapserver Thick (web map server)Map Server Thin (Feature Server) Thin (web browser)Map Client Thick (Java Applet) Client: - Display Server: -Rendering - Generation - Selection of visual elements Server: - Generation - Selection of visual elements Client: -Display -Rendering Client: -Display -Rendering -Generation Server: - Selection of visual elements