GIS in the Internet - architectures, standards and OpenSource

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GIS in the Internet - architectures, standards
and OpenSource
Team SPADE Spatial Decision Support
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GIS in the Internet - architectures, standards
and OpenSource

• Internet GIS-Overview

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GIS in the Internet Comparison to standard GIS
Standard GIS Internet GIS
Data acquisition Yes No
Preparation, processing Yes No
Database connectivity Yes Yes
Analysis and transformation Yes No Limited
Information und query Yes Yes
cartographic presentation Yes Limited No Limited
integration into available interfaces Yes Limited Yes
Processing of RASTER and vector data Yes Yes Limited
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GIS in the Internet standard architectures
special application software
web-client (Browser)
?
WAN
LAN
GIS-Software
web server
Middleware DBMS-Interface
Internet GIS
?
RDBMS
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GIS in the Internet standard architectures

• 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

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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

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GIS in the Internet - architectures, standards
and OpenSource

• Internet GIS- Some open-source and freeware
  products

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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.

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A) UMN MapServer architecture
Html/Script/Java
WAN
httprequest (URL)
Raster imageor XML text
Web Server
MapScript(Perl, PHP,Java)
Cgi-bin
Geodatafiles.shp
.Map file
Html template
RDMSOracle, MySQL...
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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

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Example UMN MapServer
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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

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B) Degree Framework architecture
WAN
WAN
Web Server
local WFS
WMS-servlet
httpXMLGML
http requests
XMLcapabilities
XMLcapabilities
Server
WFS-servlet
XMLcapabilities
Geodatenfiles.shp
RDMSOracle Spatial, JDBC-databases
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B) Degree WMS client-example
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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!!) -gtAll
  products support also thick clients !!

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General possible architectures for OGC mapserver
Thin (web browser) Map Client Thick (Java
Applet)
Client - Display

• Client
• Display
• Rendering

• Client
• Display
• Rendering
• Generation

Server-Rendering - Generation - Selection of
visualelements
Server - Generation - Selection of
visualelements
Server - Selection of visualelements
Thick (web map server) Map Server Thin (Feature
Server)
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• Thank You!