A Roadmap of Open Source components for GI Web Services and Clients A Paul R Cooper MAGIC

Outline Overview of GI web service architecture Standards Databases Web servers GIS Server software Client software Close

Overview of Architecture

Overview of Web services User interfaces with Client Software. Client Software talks to Server software. Server software contained by Web server. Server Software gets data from Data Store. Web Server Client Datastore Geoserver

Standards

Why should we be bothered? Everyone in my field/organization uses International standards allow cross-discipline data sharing. GIS crosses disciplinary boundaries. GIS allows data from different fields/disciplines to be brought together Discipline specific formats do not promote data sharing across disciplines

Standards All web services depend on standards Geographic data use OGC standards (Open Geospatial Consortium) ISO TC211 standards also important OGC and ISO are convergent Both depend on W3C standards XML, CSS, HTML, XHTML, DOM

OGC standards: Web Feature Service Web Map Service Styled Layer Descriptor GML (also ISO 19136) Filter Encoding

ISO Standards Plenty to choose from! Full list at Ones that are of interest to us are: ISO (Feature Cataloguing). ISO (Spatial Referencing by Coordinates) ISO (Spatial Referencing by Geographic identifier) ISO and ISO (Metadata) Plus lots more. ISO standards not free, unfortunately.

Web standards XML HTML and XHTML CSS Document Object Model (DOM)

Other standards SQL (ISO 9075 with OGC extensions) KML (recently adopted as OGC standard; may converge with GML)

Datastores

Any means of storing geographic information Spatially enabled RDBMS PostGIS/PostgreSQL (F/OSS) MySQL (F/OSS) Oracle (Proprietary; Oracle Spatial not required) ArcSDE (Proprietary) File based Shapefiles (Proprietary but published and widely used) Images (Many formats; mostly standard) GML (OGC standard) Service based – other WFS servers

Web servers

Web Servers Apache Stable, and well known web server. Supports CGI based services Web servers supporting Java Tomcat Jboss Jetty GlassFish

GIS Web Server

F/OSS Web servers MapServer Geoserver Deegree Probably lots of others!

Client Software

Many options of varying complexity Simple image, using a suitable URL Custom JavaScript OpenLayers Google Earth GIS Software

Using an IMG tag Provides a static view No interactive facilities E.G Ship track in static context Uses a URL specifying: The features to be displayed The area to be displayed The bounding box The SRID

Javascript based clients WMS Calls can be scripted in JavaScript The ADD used this approach until recently! Advantages Very customizable Can be adapted to suit your environment Disadvantages No support Gets complicated quite quickly! Only supports WMS

OpenLayers An AJAX system Can use wide variety of data sources WMS WFS Images Actively being developed Stable and widely used. Documentation not wonderful!

Google Earth Google Earth can view WMS Some WMS will provide KML output as an option Geoserver does this KML is an output from a WMS Not a data transfer format

GIS Packages Most mainstream GIS has at least limited capability to use WMS/WFS.

Summary

F/OSS software provides good support for GI Web services F/OSS software provides good compliance with relevant standards F/OSS provides stable solutions F/OSS is easy to use!

Thats All Folks!