Data Services Task Team

1
Data Services Task Team

• By Wyn Cudlip
• Based on presentation by
• George Percivall
• to Subgroup Meeting in Osaka, March, 1999
• Percivall_at_harp.gsfc.nasa.gov

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Data Services Task Team - Proposal

• Background
• Users want direct access to the data in real time
• Build on Access Subgroup methods to locate and
  order data
• Build on Data Subgroup developments in data
  interoperability
• Relate CEOS data services needs to ISO TC 211 and
  OGC activities
• Draft Purpose
• Develop a conceptual model of EO needs for
  accessing and manipulating data in real time over
  a distributed computing environment.
• EO needs and technical feasibility determined
  through review of existing implementations for
  direct access to data review of existing and
  emerging standards and the expertise of the task
  team.

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Survey of Data Services Concepts

• Scenario
• Access Topics
• Data Interchange
• Services
• Portrayal
• Revenue Model for Access
• Existing Products/Implementations
• http//sgt.sgt-inc.com/george/CEOSacc/CEOSmain.ht
  ml

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Reference Model Architecture with Three Tiers
Web Browser
Application Server
Catalog Services Service Registry Portrayal
Services
Data Provider
Data Provider
Data Provider
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Data Access Scenario

• User identified Landsat scenes of interest at a
  Data Provider using a Catalog Service
• 1. User interacts with Service Registry to find a
  land cover Classification Service and determines
  what parts of Landsat Data are needed
• 2. User reviews services available from the
  Landsat Data Provider e.g., sub-selection on
  bands and compression
• 3. User requests Landsat data be subsetted on
  bands 1-5, compressed, and made available for
  on-line retrieval
• 4. User provides the Classification Service with
  a reference to data created in Step 3
• 5. Classification Service performs the
  classification and creates output available for
  on-line retrieval
• 6. User locates a USGS Quadrangle Map of the
  geographic area to use as base map
• 7. User provides Portrayal Service with
  references to Landsat images (step 3),
  Classification results (step 5) and USGS base map
  (step 6)
• 8. User provides Portrayal service with
  parameters for generation of image
• 9. Portrayal service creates the image,
  available for access by the User's browser.

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Topics in Data Services

• Data Interchange
• schema (description)
• encoding
• Access Services
• taxonomy (classification)
• service request framework
• Portrayal
• Revenue Model

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Data Interchange
8
Schema and Encoding

• Application Schema built from Conceptual Schemas
• Spatial Schema
• Temporal Schema
• Portrayal Schema
• Quality Schema
• Feature Catalog
• Metadata Schema
• Encoding of Schemas
• All TC 211 Schema are defined using UML
• All Schemas are transferred using XML
• XML Metadata Interchange (XMI) under
  consideration
• Encoding of Data
• Encoded using XML?
• Basic Data Types in TC 211 not sufficient for
  Gridded Data

TC 211 Conceptual Schema
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TC 211 OGC Services Taxonomy

• Geospatial Information Access Services
• Feature Generalization Services
• Geospatial Catalog Services
• Geospatial Information Extraction Services
• Geospatial Coordinate Transformation Services
• Geospatial Annotation Services
• Imagery Manipulation Services
• Geospatial Manipulation Services
• Imagery Exploitation Services

• Geospatial Analysis Services
• Exploits a Feature Collection to derive
  mission-oriented quantitative results.
• Geospatial Registration and Adjustment Services
• Geospatial Symbolization Management Services
• Geospatial Dissemination Services
• Image Map Generation Services
• Image Synthesis Services
• Image Understanding Services
• Geospatial Display Services

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Service Domains
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Geospatial Services
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ECS Data Type Services

• Subsetting and Subsampling
• Mean, Median and Mode of like parameters with a
  data product
• Map projections from geographic latitude and
  longitude coordinates
• Display
• browse, time series, scatter plot
• Data Dissemination
• reformat the data set in ECS HDF format.

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Portrayal
Example from BBN OpenMap in context of OGC WWW
Mapping
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Revenue Model for Services

• Free to User
• Demo version ala translator on Alta Vista
• Supported by Advertisement
• Supported by an Agency
• License problem Renting an application typically
  not allowed
• Charge the User
• Micropayment ecash, cybercash, cybercoin
• Subscription service Pay in advance
• Credit Card

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Existing Products/Implementation Examples

• HDF API libraries
• NetCDF API libraries
• DIAL
• DODS
• OGDI
• CubeWerx Inc.
• ESRI SDE
• Microsoft TerraServer
• PCI EASI/PACE
• Grid Analysis and Display System (GrADS)
• Research Systems Inc, e.g., IDL
• Environment for Visualizing Images (ENVI)
• Khoros
• NOAAServer Scientific Graphics Toolkit (SGT)

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Data Services Activities

• Contribute to New Work Items in TC 211
• Imagery and Gridded Data
• Coverages (based on OGC Coverages work)
• Contribute Earth Observation (EO) needs to TC211
  Schema and Encoding
• Abstract data models for EO, e.g., grid, swath,
  point
• Basic data types for EO data
• Develop EO Services Taxonomy
• Develop based on current services in EO Products
• Submit to TC 211 and OGC as CEOS input
• Review OGC Portrayal demo
• Does Portrayal demo work for Earth Observation
  Data?
• Evaluate existing products/implementations