Former developments of the Sensor Observation Service

SOS adapter implementation

adapter for 52N-SOS-spec-0.9-rel-1.0 (ASOS)

• implementation finished

adapter for SOSv2

• implementation finished

--> see OX-Framework for more details!

52N-SOS-spec-0.9-rel-1.0 (ASOS)

This release is based on the OGC Sensor Colleciton Service specification document. In addition, it was enhanced to enable the user to regiser threshold value conditions for specific observables (Active SOS). If the condition is met, the ASOS sends O&M encoded data. There for the ASOS provides the SubscribeObservation and the UnsubscribeObservation interfaces. A person who is interested in sensor data (consumer) concludes a contract with the ASOS via the SubscribeObservation operation. The contract (subscription) specifies the conditions for the data supply. The UnsubscribeObservation interface of the ASOS makes it possible to abolish a subscription.

implementation log

• 2004-12-20 support for gzip O&M implemented
• 2005-04-13 optional operations (DescribePlatform &DescribeSensor) implemented
• 2005-04-15 HTTP-GET support for theGetCapabilities operation implemented
• 2005-04-28 O&M package separated from the scs package
• 2005-06-09 release of SOS v.1.0 (52N-SOS-spec-0.9-rel-1.0.0)
• 2005-10-05 design of the new SOS finished
• 2005-11-02 getCapabilities operation implemented
• 2005-11-30 getObservation operation implemented
• 2005-12-10 describeSensor operation implemented
• 2006-01-13 ant build script finished
• 2006-01-28 implementation and documentation of the new SOS finished, writing How-to-install started
• 2006-02-08 How-to-install finished, Testing started
• 2006-02-14 Testing finished, quality assurance started, Implementation of a Feeder Framework for inserting values into the database started
• 2006-03-01 release of SOS-v2-00-00
• 2006-03-14 change to PostGIS versions upper than 1.0.0 finished
• 2006-03-23 implementation of the feeder framework for inserting data into the SOS database finished
• 2006-04-20 Testing and modulation of How-to-install finished. Quality assurance started. Implementing of getResult started
• 2006-05-16 release of SOS-v2-01-00
• 2006-06-13 implementation of CommonObservation and CompositePhenomenon support finished
• 2006-07-12 implementation of getResult operation finished, testing started
• 2006-08-12 testing finished. Start of conceptual design for SOAP SOS started.
• 2006-09-25 data model optimized to enhance performance of getCapabilities operation; subpackages pgsql80 and pgsql81 of package org.n52.ds.pgsql created which contain the classes for the specific postgreSQL versions.
• 2006-11-30 Revision of time handling. Timestamps have to be in ISO8601 format (YYYY-mm-DDThh:MM:ssZ; example: 2006-11-30T22:30:25+02) and with a two digit timezone
• 2006-12-08 Implementation of getFeatureOfInterest method started
• 2007-01-05 Logging changed to log4j and improved. GetFeatureOfInterest method by ID finished.
• 2007-03-05 Redesign of O&M encoding and implementation of new O&M finished; SOS and SosFeeder seperated into two different projects on sourceforge CVS
• 2007-05-03 Implementation of quality integration finished. ATTENTION: datamodel has changed!!

SOS performance tests

Performance tests for every single operation were performed for the example application. The tests were executed with the Microsoft Web Application Stress Tool. The tested SOS was running on a Server with Hardware:

• Intel Pentium4 2,6 GHz
• 1,5 GB RAM

Software:

• OS: Windows XP Professional
• Server: Apache Tomcat 5.5

All tests were executed with a execution time of 10 min. The underlying database contained 26.700 observations at the testing time. The following results were obtained:

• GetCapabilities operation:
  • with 1 Client:
    • requests per second: 6.35
    • average time until response was received (in Milliseconds): 2066.33
• DescribeSensor operation:
  • with 1 Client:
    • requests per second: 12.15
    • average time until response was received (in Milliseconds): 9.93
• GetObservation operation:
  • with 1 Client for 1 Observation:
    • requests per second: 1.56
    • average time until response was received (in Milliseconds): 636.22
  • with 30 Client for 1 Observation:
    • requests per second: 3.21
    • average time until response was received (in Milliseconds): 4717.34
  • with 1 Client for 1 Day and 1 Station (about 100 Observations/response):
    • requests per second: 2.11
    • average time until response was received (in Milliseconds): 469.34
  • with 30 Clients for 1 Day and 1 Station (about 100 Observations/response):
    • requests per second: 2.05
    • average time until response was received (in Milliseconds): 2879.99
  • with 1 Client for 1 Month and 1 Station (about 1.8 MB size of response document):
    • requests per second: 0.05
    • average time until response was received (in Milliseconds): 15882.67
  • with 30 Clients for 1 Month and 1 Station (about 1.8 MB size of response document):
    • requests per second: 0.13
    • average time until response was received (in Milliseconds): 29948.88

-- ChristophStasch - 20 Jan 2007