StreamStats: System Design and Web Implementation

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StreamStats System Design and Web Implementation

• 12/18/02
• Jacque Coles - USGS Dean
  Djokic - ESRI

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System Design Core Concepts (1)
Map Server (ArcIMS)
Client (IE 5.5)
Data Server (ArcSDE)
Web Server (IIS, ASP)
Client (IE 5.5)
Client (IE 5.5)
Application Server (ArcMap, NFF)
Database (SQL Server)
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System Design Core Concepts (2)

• Web, Application, Map, and Data Servers are
  separate machines (but could be combined
  depending on the load and performance
  requirements).
• Current design is based on Windows platform.
• Scalability for Application Servers is
  accomplished by adding more physical servers
  (computers) with ArcGIS on them.

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Processing Roles (1)
MS
DS
WS
AS

• Web Client requests map activity (zoom in/out,
  delineation at a point, etc.)
• The request is sent to the Web Server.
• If the request is one for standard map
  operations, it is forwarded to the Map Server
• If the request is for watershed delineation/NFF
  computations, it is forwarded to the Application
  Server
• Web Server maintains connection between the
  client and the Map and Application Servers.

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Processing Roles (2)
MS
DS
WS
AS

• Application Server performs watershed delineation
  and characteristics extraction (ArcGIS) and flood
  frequency computations (NFF). The results are
  stored in the database through the Data Server
  (ArcSDE).
• Communication between the Web and Application
  Servers is through a dedicated socket port.

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Processing Roles (3)
MS
DS
WS
AS

• Map Server (ArcIMS) manages standard
  internet-based mapping activities (zooming,
  panning, turning layers on and off, etc.). Data
  for map-based operations reside in the database
  accessible through the Data Server (ArcSDE).
• Application and Map Servers do not communicate
  directly, but they do share the same database.
  Communication between the two is via Web Server.

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Processing Roles (4)
MS
DS
WS
AS

• Data Server (ArcSDE) stores the data for the
  Application Server and serves the data to the Map
  Server.

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USGS Streamstats Hardware

• Web Server
• Dell PowerEdge 1650 Pentium III, 1.26GHz Single
  Processor
• 512MB SDRAM
• Two 36GB SCSI 160 Drives
• RAID 1
• Application Server
• Dell PowerEdge 2500 Pentium III, 1GHz Dual
  Processors
• 1GB SDRAM
• 6x36GB SCSI U3/160 Hard Drives
• Tape Backup
• RAID 5

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USGS Streamstats Configuration
IIS, ASP ArcIMS
ArcMap ArcSDE SQL Server Data, NFF
Web Server
App. Server
Request to ArcMap
Response from ArcMap
Request to IMS
Response from IMS
Internet
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Communication Between Server Applications

• ASP routes requests to either IMS or Application
  server
• IMS handles map related requests ZI,ZO,Pan
• Application server handles application specific
  requests
• Application server has an open port for ASP to
  communicate with ArcMap
• Deliniation polygon returned to IMS for Web
  viewer
• GetParameters parameters related to topographic
  and hydrologic data returned to IMS for Web
  viewer

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Communication Between Server Applications (2)

• Programming was done by ESRI Denver and Redlands
• ASP, VB, ArcIMS and ArcObjects on server side
• JavaScript and DHTML on the client side
• Salmon and Clearwater basins (25,000 sq. mi.
  18 cataloging units) to be implemented by the end
  of January on the Idaho servers for restricted use