View
213
Download
0
Category
Preview:
Citation preview
Service Composition Service Composition for GISfor GIS
Sai Ma, Minruo Li, Weichang Du
Faculty of Computer Science,
University of New Brunswick, Canada
2008 IEEE Congress on Services 2008 - Part I
69721027 郭建國
OutlineOutline
Introduction Geographical Information System(GIS)
Background OpenGIS WMS & WMC
Solution SOA Framework for GIS Map Services Composition via BPEL
Implementation & Demonstration Perspective & Conclusion
What is GIS?What is GIS?
Geographical Information System Provide a method to visualize , analyze and
manipulate geospatial data. Geographical maps via Services
Consider the process of visualizing , analyzing and manipulating geospatial data as services.
An issue within the GIS community Various geospatial data are stored in different
data formats suitable for different systems.
OpenGIS WMS & WMC
Web Map Service (WMS) Be used to publish a map service Based on XML Schema
Web Map Context (WMC) Describes an instant map view information
Web Map Service
Operations GetCapabilities GetMap GetFeatureInfo
Web Map Service
GetCapabilities request URL
Web Map Service
The parameters of a GetMap request
Web Map Service
The parameters of a GetFeatureInfo request
Web Map Context
In contrast to WMS , WMC describes an instant map view from the perspective of the map creator , which contains the WMS layer components , the bounding box and map title.
Map Services Composition via BPEL We use ActiveBPEL as the tool to handle all
BPEL related work in our application system. Configure Database
Gathers as many existing maps services and parses them into database
Solution with SOA and BPEL
Generate Business Process
Map Services Composition via BPEL Generate Business Process
NewMapViewRequest AssignRequest WMFSFlow InvokeWMS1 & InvokeWMS2 CompeseLayers InvokeMapCreationService AssignResponse NewMapViewResponse
Map Services Composition via BPEL
NewMapViewRequest Get URL, layer name, bounding box, format, height, and
width information from WMS1 and WMS2. AssignRequest
Initializes parameters “wms1Url”, “wms1LayerName”, “bbox”, “format”, “height”, and “width”
Assigns these parameters to each “InvokeWMS” activity in the “WMSFlow”.
In the mean time , create “wms1Result” and “wms2Result” to hold each URLs resulting from previous WMS.
Map Services Composition via BPEL Combine the two map layers, add an opening
tag “<layer>” in front of “wms1Result” and a closing tag “</layer>” at the end of it, do the same change to “wms2Result”.
“<layers>” and “</layers>” are added to group all “<layer>” element toghther.
Map Services Composition via BPEL
Map Services Composition via BPEL
WMFSFlow Get information from AssignRequest Invokes WMS1 and WMS2 in parallel
InvokeWMS1 & InvokeWMS2 CompeseLayers
Concatenate the two URLs into one single string and pass it to “InvokeMapCreationService”
InvokeMapCreationService Create a new image by calling external JAVA libraries to
read each map layer pixel by pixel
Map Services Composition via BPEL
AssignResponse Assigns the resulting URL to “NewMapViewResponse”
NewMapViewResponse Responds to the map creator by delivering this URL to
map creator.
Map Services Composition via BPEL Two additional activities will be added
“ApplyTemplate” and “AssignLayers” To apply some predefined templates to add
site-specific information to the new map during the map creation process Such as company logo or name.
Map Services Composition via BPEL
ApplyTemplate Applies some predesigned map templates before
creating the new map AssignLayers
Adds the “layers” variable to the template response and passes it to the “InvokeMapCreationService”.
Interface
Interface
Publish WMC
Export the .bpel file
WMS Map Protal ID:SOC2008 PASSWORD:SOC-2008
Recommended