Use Case AQ.SatelliteData.1.a[edit | edit source]
Purpose[edit | edit source]
Earth Information Exchange
Access to satellite data using queries over a continuous space-time-parameter domain.
Revision Information[edit | edit source]
Prepared by: Rudolf Husar Washington University
Stefan Falke Washington University and Northrop Grumman IT - TASC
created: February 26, 2007
Modified by <Modifier Name/Affil>, <Date/time>, <Brief Description>
Use Case Identification[edit | edit source]
Use Case Designation[edit | edit source]
Use Case Name[edit | edit source]
Short name: Satellite data access
Long name: Air quality user-access to satellite data by space-time-parameter queries
Use Case Definition[edit | edit source]
The AQ cluster has a fundamental need for a set of CORE web services that allow meaningful user-access to satellite data. These services include:
- Data access by space-time-parameter query on granules
- Subsetting that clips the data to user-specified BBOX
- Mosaicing that splices granule mosaic into a coherent dataset
The proper chaining of these services results in a higher order service, WCS, that returns the requested satellite data for the BBOX, Time, Parameter. Not more not less. Such a WCS service was in fact used in the Web service chaining experiment. Extending that service to return numeric satellite data (not just images) is the goal.
Actors[edit | edit source]
Primary Actors[edit | edit source]
Air quality analysts interested in using satellite data for assessing air pollution, comparing satellite and surface data, "ground-truthing" model results.
Other Actors[edit | edit source]
Preconditions[edit | edit source]
- 1. Satellite data are available through open interfaces
- 2. Data access service specifications, e.g. OGC Web Coverage Service (WCS), can be implemented by data provider or mediator
Postconditions[edit | edit source]
- 1. Satellite data in a numeric data format (as opposed to image format) covering the spatial area, time range, and parameters that were specified in the query.
Normal Flow (Process Model)[edit | edit source]
- 1) The user finds a WCS serving satellite data
- 2) The user submits a WCS GetCoverage request that includes bounding box, time, and parameter filters
- 3) The satellite data server provides the data that meets the query criteria. In the process, the data provider may need to execute swath mosaicking and data subsetting services.
Alternative Flows[edit | edit source]
Successful Outcomes[edit | edit source]
- 1.Operation succeeds and user obtains satellite dataset adhering to the requested spatial, temporal, and parameter filters.
Failure Outcomes[edit | edit source]
Special Functional Requirements[edit | edit source]
Extension Points[edit | edit source]
- AQ.SatelliteAccess.1.b: NASA GSFC DISC implementation of WCS for OMI NO2 access