User access to satellite data
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Latest revision as of 16:52, 11 July 2007
 Use Case AQ.SatelliteData.1.a
Earth Information Exchange
Access to satellite data using queries over a continuous space-time-parameter domain.
 Revision Information
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
 Use Case Designation
 Use Case Name
Short name: Satellite data access
Long name: Air quality user-access to satellite data by space-time-parameter queries
 Use Case Definition
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.
 Primary Actors
Air quality analysts interested in using satellite data for assessing air pollution, comparing satellite and surface data, "ground-truthing" model results.
 Other Actors
- 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
- 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)
- 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
 Successful Outcomes
- 1.Operation succeeds and user obtains satellite dataset adhering to the requested spatial, temporal, and parameter filters.
 Failure Outcomes
 Special Functional Requirements
 Extension Points
NASA GSFC DISC implementation of WCS for OMI NO2 access