Next Generation Web Mapping

1. Next Generation Web Mapping Web-based Mapping for the 21st Century Archaeologist Bill Dickinson Jr. GEOG 596A, Spring 2007 Penn State World Campus MGIS Program

2. Overview • Evolution of Web-based Mapping • Next Generation Mapping • An Archaeological Application • 2D Mapping Client • 3D Mapping Client • Conclusion

3. The Evolution of Web-based Mapping

4. Previous Generation • Client technology • Static map image with single level of detail exposed as flat image file on web page. • User interface features limited to form-based HTML information requests. • Geospatial toolset limited to moving around flat image within single level of detail (pan). • Server technology • Map images generated on-the-fly and temporarily stored as a single image file. Changes in level of detail required generating a new map image. • Client-server communication through complex HTTPRequest strings passed to map server through web forms. • Limited spatial capabilities accessed through restrictive and proprietary XML variants (ArcXML and GML). • ArcIMS 4.0, Web Mapping Server (WMS). Client Server “Dumb” map Limited spatial capabilities. Broad spatial capabilities. “Smart” mapping application

5. Client Server “Dumb” map Limited spatial capabilities. Broad spatial capabilities. “Smart” mapping application Current Generation • Client technology • Dynamically generated map image with multiple levels of detail exposed as flat image file on web page. • User interface features primarily graphical in nature (I.e., buttons) that activate associated application actions. • Geospatial toolset expanded to navigating through the map (zoom in, zoom out, pan) as well as a small set of geoprocesses available to the user (query, geocode, buffer). • Server technology • Map images still generated on-the-fly and temporarily stored as a single image file. • Client-server communication expanded to include ASP-postback in .NET web applications. • Expanded spatial capabilities accessed through restrictive and proprietary XML variants (ArcXML and GML). • ArcIMS 8.x/9.x, ArcGIS Server 9.0-9.1, Web Feature Server (WFS).

6. Client Server “Dumb” map Limited spatial capabilities. Broad spatial capabilities. “Smart” mapping application Next Generation • Client technology • Highly interactive, dynamically generated map views with unlimited levels of detail exposed as tiled image caches. • User interface features are fluid and generated on an as-needed basis depending on user actions, closely mimicking traditional desktop mapping clients in responsiveness and scope of features. • Geospatial toolset expanded to full suite of traditional desktop mapping applications (layer manipulation, attribute manipulation, surface analysis, 3D analysis, etc.) as well as unique, highly-customized geospatial tools for specific user groups. • Server technology • Map images stored as pre-generated, tiled map caches at multiple levels of detail for fast retrieval and transfer to web client. • Client-server communication through SOAP, REST, or RPC calls. • Broad spatial capabilities (including 3D visualization) exposed as web service end-points using a flexible geospatial XML variant (KML). • ArcGIS Server 9.2, ArcWeb Services, GoogleEarth Server, SpaceTime Mapping Server.

7. Next Generation Mapping

8. NextGen Map Applications • New client technologies will provide multiple users with an experience very similar to a traditional desktop client. • New server-side approaches will provide for extremely fast data transfers of map imagery for both 2D and 3D client interfaces. • New geospatial web services will provide for a very large geospatial toolset that could be consumed by many different client technologies in whatever combination desired by the individual user.

9. Service Oriented Architecture There is no widely-agreed upon definition of service-oriented architecture (SOA) other than its literal translation that it is an architecture that relies on service-orientation as its fundamental design principle. Service-orientation describes an architecture that uses loosely coupled services to support the requirements of business processes and users. Resources on a network in an SOA environment are made available as independent services that can be accessed without knowledge of their underlying platform implementation. -- Wikipedia, 17 May 2007

10. Data Stores Clients Web Services KML/ SOAP KML/ SOAP Web Mapping Architecture • Geospatial tools are developed as loosely coupled, independent web service packages. • Mapping applications are accessed through standard web technologies to meet the needs of a specific business process or user.

11. Benefits of SOA • Allows for distributed, web-based mapping applications that can be rapidly engineered for each unique need. • Accessible to the widest possible user-base with the smallest application footprint possible on the local computer. • Connects light-weight mapping client applications to relevant geospatial and legacy data stores. • Leverage server-side geoprocessing tools for distributed analysis.

12. An Archaeological Application

13. The North Orkney Historic Population Project • Examine changes in demography, economy, settlement, and land-use in the north Orkney Islands (Westray, Papa Westray, Faray, Eday, Sanday, and North Ronaldsay). • Period of interest is c. AD 1735-2000, which witnessed two transition trends: • From traditional subsistence production based on small-scale farming and fishing to modern system of beef production for external markets. • From sustainable demographic regime with limited migration to system with substantial out-migration, depopulation, and population aging. • Project intended to study the spatial relationship between the factors in an attempt to better understand the forces of demographic change in a relatively contained population.

14. Project Assumptions • New models of demographic change should be explicitly spatial in nature. • “Homeostatic demographic regimes” (a population in equilibrium sorted by clusters of habitats from which necessary resources are drawn) have both temporal and spatial dimensions. • Modern demographic change always involves a significant reorganization of population across space. • Remotely sensed imagery should provide new perspectives on the environment of the study population. • The northern islands of Orkney are virtually treeless, providing near-optimal conditions for the use of remote sensing as an environmental and archaeological survey method.

15. Identified Mapping Tasks • Geo-reference all house sites(buildings) and link them to households (people). • Link existing information on topography and soils to new data taken from aerial photography and satellite imagery. • Digitize and geo-reference cadastral maps, rentals, tax valuations, and other old documents kept on-island or in the Orkney Archives (Kirkwall, Orkney). • Test new demographic theories in a spatially heterogeneous environment. • Link all data in a single GIS system.

16. Map Application Requirements • Use ArcGIS Server as data store and geoprocessing backend. • Combine project raster (satellite imagery and scanned paper maps) and vector (points, lines, polygons) data into single interface. • Provide access to specialized project “business logic” (i.e., demographic change analysis tool).

17. Applying NextGen Mapping • NextGen web-based mapping applications are built on a “loosely coupled” architecture, which makes it ideal for combining disparate functions into a single user interface. • ArcGIS Server can expose map services using various “open” methods used in NextGen mapping applications. • NextGen applications use standard internet graphics files to display both raster and vector data in the user’s web browser of choice. • Specialized business logic is accessed through custom web services hosted on the server. • Additional benefits: • Allow end-user’s to access project data independent of computer platform or location. • Provide a means for users to collaborate even if separated by large geographical distances. • Use a client interface (a web browser) that is nearly ubiquitous in the world today.

18. 2D Mapping Client

19. Adobe Flex • 2D Streaming Map Application • Flash-based technology • ActionScript 3.0. • Vector graphics engine. • Embedded in modern browsers with plug-in. • Enhanced with ESRI’s Flex SDKfor rapid application development. • Uses ArcGIS Server 9.2 forbackend geoprocessing tasks and data storage. • Leverage ESRI’s new ArcWeb Services (AWS) tools. • http://www2.arcwebservices.com/v2006/index.jsp • Access data from more than 20 leading commercial mapping data and content providers. • Access standard geoprocessing web services (geocoding,queries, find-a-place, and more).

20. Basic Tools • Basic map application tools: • Spatial navigation (zoom in, zoom out, pan, full extent, zoom to layer, zoom to feature, spatial bookmarks, etc.). • Spatial analysis (buffer, query, identify, geocode, etc.). • Spatial editing (create/delete/move/modify feature or records). • ESRI’s generic Flex interface can be found at http://www.arcwebservices.com/awx/index.jsp. • Shows basic toolset as well as gives feel for how Flex mapping client will perform.

21. Advanced Tools • Embed streaming media. • Streaming audio and video can be easily embedded in a Flex application. • Audio interviews can be accessed geospatially through map interface, given analysts ability to review audio records within the application. • http://www.amgentourofcalifornia.com/docroot/tourtracker2/index.html • User collaboration. • By adding Adobe’s Flex Data Services (FDS) on the server, dynamic user collaboration can be achieved through the mapping application. • Collaborative features can include: • Single web user controlling the application experience for multiple users. • Editing of data by one user can automatically be pushed through to all other users.

22. Project Tools • Specialized project tools: • Population well-being algorithm exposed as web service. • Will allow for dynamic input of algorithm parameters so that analyst can “tweak” the output depending on various factors. • Timeline viewer. • Will allow analyst to dynamically apply a time filter to the spatial data to look for spatiotemporal patterns in the underlying data. • Data can be “played” through time (backward and forward) for further analysis. Simile Timeline, a DHTML-based AJAX widget for visualizing time-based events. (http://simile.mit.edu/timeline).

23. Flex Pros and Cons • Benefits • Streaming application means minimum features are downloaded immediately with the bulk of the application loading in the background. • Vector engine will allow for smoother vector data layers to be drawn internal to the client. • Vector data can be retrieved from server as simple XML feed and then converted to 2D features locally, reducing the data transfer load and increasing the responsiveness of the map application. • Can take advantage of local computers graphics card for data visualization. • ActionScript 3.0 is a full-featured Object-Oriented (OO) programming language and will provide for more intensive geoprocesses to be built directly into the client. • Drawbacks • Requires browser plug-in, which can be a deterrence to some users. This is offset by the fact that all modern web browsers come with the Flash player pre-installed.

24. 3D Mapping Client

25. 3D Visualization • 3D is truly the next generation of mapping applications. • Will provide new ways to analyze data not available with 2D “flat” maps. • Potential 3D client options: • Flex 3D • GoogleEarth • SpaceTime Java3D Client • ArcExplorer (AGX)

26. Flex 3D • Advantages • Would be internal to web-based client. • Best performance for vector-based 3D due to Flash graphics engine. • Disadvantages • Unproven technology that would potentially require significant development time to realize. • Would have to convert a Flash 3D library into something that could be used in a Flex mapping application. • Sandy 3D Flash Library (http://www.flashsandy.org/). • Away3D Engine (http://away.kiev.ua/away3d/). • Would have to limit 3D experience to vector representations as the use of raster data is not viable yet.

27. GoogleEarth • Advantages • Basic viewer is free. • Best mapping 3D data visualization tool currently on the market. • ArcGIS Server can publish data as KML services, which are consumed natively by GoogleEarth client. • Free access to current high resolution satellite imagery for nearly all parts ofthe world. • Development path for creating 3D models of real world objects. • Disadvantages • Not in web browser - need to download stand-along client. • Useful tools are only available with purchase of most expensive client license ($400). • Closed API - developing customized extensions is a very expensive route.

28. SpaceTime Java3D Client • Advantages • Agile 3D analysis and display environment. • Deployed in modern web browsers. • Will run on any platform with Java3D libraries installed on system. • Built-in support for spatiotemporaldata visualization through GeoRSS feeds. • Easily extensible for customized geoprocessing needs through exposed web services. • Disadvantages • Requires Java3D libraries to be installed and configured on local computer. • Potentially longer development time to embed desired tools within client.

29. ESRI ArcGIS Explorer • Advantages • Best full-featured GIS 3D mapping client currently on market. • Geoprocessing capabilities easily extended with complete suite of ESRI geoprocessing tools as seen in ArcMap. • Can connect directly to ArcCatalog data source. • Disadvantages • “Thick” client - completely separate, stand-alone mapping application. • Requires expensive user licenses. • Not web-based, though it can connect to remote data sources through the HTTP protocol. • Performance is not as good as other options. • Requires a lot of local computer resources (CPU, RAM) for best performance.

30. Conclusion • Outcome of proposed project: • A Next Generation web mapping application using a Service Oriented Architecture. • A 2D web client built on Adobe Flex 2.0 and ESRI’s ArcWeb Services SDK. • A 3D web client using the SpaceTime Java3D web client. • Specialized business logic exposed as independent web services using the SOAP communication protocol. • Questions?