Web GIS
Oregon Explorer
Marc G Rempel
Oregon State University
The Valley Library
Oregon Explorer
marc.rempel@oregonstate.edu
What is the
Oregon Explorer?
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Natural Resources Digital
Library
Place-based resources
Supports informed natural
resource decision-making
Evolution of the Oregon Explorer
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Basin Portals
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Topic Portals
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e.g. Willamette Basin Explorer
e.g. Land Use Explorer
Data Portals
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e.g. Imagery Explorer
Oregon Spatial Data Library
Components of Web GIS
1. Spatial Data
2. Web Server
3. Map/GIS Server
4. Mapping Application
5. Application Enhancements
(optional)
MapServer example
Components of Web GIS- Spatial
Examples of Spatial Data:
Shapefiles/ Geodatabases (ESRI)
KML/KMZ (Google Earth)
GeoRSS/GeoJson
Web services
WMS – Web Mapping Services (image)
WFS – Web Feature Services (vector)
WCS – Web Coverage Services (raster)
Data
Components of Web GIS- Web
Server
Examples of Web Servers:
Apache Tomcat
IIS (Windows)
Web Servers provide the foundation for serving out data on the web.
Components of Web GIS- Map/GIS
Examples of Mapping Servers:
ArcIMS
ArcGIS Server
GeoServer
MapServer
Servers
Components of Web GIS- Map/GIS
Servers
Role of Map/GIS Servers:
1.
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3.
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5.
Serve spatial data via the internet.
When a request comes to the web server, the Map/GIS
server application handles the request and returns a map
image, attribute, geometry or downloadable data.
The Map/GIS server can also return images of legends, scale
bars and reference maps.
Requests can query the spatial data and return only the data
that matches the request.
Some Map/GIS servers also support geometry, geocoding
and geo-processing tasks requests. (i.e. buffer queries,
clipping, etc).
Components of Web GIS- Map/GIS
Servers
Map/GIS Server Services
1.
A Map/GIS server can have multiple services of various types.
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2.
3.
4.
Map service
Geoprocessing service
Geodata service
Image service
Geometry service
Geocoding service
Globe service
A map service is a specified grouping of spatial data with projection
and display information defined. For ESRI, a .mxd file can serve as the
source for a map service.
A Map/GIS server can allow for map services to be started and
stopped.
A map service can support multiple output formats (WMS, WFS, KML)
Components of Web GIS- Map/GIS
Map/GIS Server Services: ESRI Example ArcCatalog
Servers
Components of Web GIS- Map/GIS
Servers
REST and SOAP API
Some Map/GIS Servers expose their services via REST and SOAP APIs.
REST API
Representational State Transfer (REST) is a stateless protocol for leveraging
representations of service data and methods.
Provides a lightweight interface to access service properties and
functionality through client side script.
Example: http://methionine.library.oregonstate.edu/ArcGIS/rest/services
SOAP API
Simple Object Access Protocol (SOAP) is a protocol for creating server side
classes and methods for a web service. SOAP tends to have more robust
capability over REST, but can be more complicated to incorporate.
Example:
http://methionine.library.oregonstate.edu/ArcGIS/services/Restoration/O
WRI_07_1/MapServer?wsdl
Components of Web GIS-
Mapping Applications
A mapping application is a web component/page that handles
requests/responses to and from the mapping server.
Typical functionality includes handling navigation panning/zooming, layer
management, attribute queries and advanced processing tasks (buffer, distance
calculations, etc).
Examples of extensible Mapping Applications:
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ESRI WebADF/JavaScript API
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Google Maps API /ArcGIS JS Extension
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Google Earth API
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Bing Maps API /ArcGIS JS Extension
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Bing Maps Silverlight API (Microsoft)
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Flex (Adobe) / ArcGIS Extension
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Yahoo Maps API
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OpenLayers API
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ArcGIS for iPhone API coming soon.
Components of Web GIS- JavaScript Class Libraries
JavaScript class libraries are an optional piece of a web GIS stack that can add some
dynamic user interface components such as sliders, pop-up boxes, dynamic table grids,
and AJAX (Asynchronous JavaScript and XML) handling.
Some popular JavaScript class libraries to consider are:
Dojo
EXT.JS
YUI (Yahoo User Interface)
jQuery
Can get from http://code.google.com/apis/ajaxlibs/
What is a mashup?
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a mashup is a web page or application that
combines data or functionality from two or more
external sources to create a new service.
The term mashup implies easy, fast integration,
frequently using open APIs and data sources to
produce results that were not the original reason for
producing the raw source data.
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Source: Wikipedia.
A simple web mapping application
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Basic HTML and JavaScript will get you a long ways.
ESRI Resource Center
http://resources.esri.com/arcgisserver/index.cfm?fa=home
Examples of Mapping Mash-ups
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Measure 37 Viewer
ORWAP
Oregon Restoration
Measure 37 Viewer
http://oeapp.oregonexplorer.info/M37Viewer
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Virtual Earth/Bing Maps- JavaScript API
Overlay WMS from ArcIMS
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Create active objects (pushpins, polygons).
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Transparency slider, legend
Uses GET_FEATURES call to ArcIMS to draw polygons.
3D Functionality.
ORWAP- Oregon Rapid Wetland Assessment Protocol
http://oregonexplorer.info/wetlands/ORWAP/
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Uses ArcGIS server map and geometry services.
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Buffers selected point and queries intersection of layers.
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Uses Virtual Earth/Bing JavaScript Extension for ArcGIS
server.
Oregon Watershed Restoration Tool
1. ArcGIS Server 9.3 mapping backend
2. Bing GeoRSS Collections for basin, subbasin and watershed council
layers.
3. REST and SOAP used for getting layer data and overlaying WMS.
4. DOJO javascript class library for more interactive user interface.