HDF AND HDF-EOS WORKSHOP I (1997)

1. An HDF-EOS DataBlade
using Informix’s ObjectRelational Database
Renu Chaudhry
ECOlogic
www.ecologic.net

2. Topics
What is an ORDBMS ?
INFORMIX-Universal Server Architecture
DataBlade Architecture
HDFEOS DataBlade Components
HDFEOS DataBlade Benefits
User Scenario
Summary

3. What is an ORDBMS ?
ORDBMS : Object-Relational Database Management System
OO features
complex data object
data behaviors (functions)
inheritance and overloading
RDBMS features
flexibility, security, transactions, recovery
Native SQL parsing, optimization
data access methods (use of R-tree & B-tree indexes)

4. INFORMIX-Universal
Server Architecture
Image
DataBlade
Module
Spatial
Web
Extending the server by
adding DataBlades
DataBlade API
Text
Extensible
OR Engine
Scaleable
Data
Manager
INFORMIX-Universal Server

5. DataBlade Architecture
Routines that act upon the new data
types
Tables containing new data types
Fast indexing and access for new
data types
Client API
Types
Routines
Tables
Access
Methods
Client
Code
DataBlade Module
Data Types to define new
information or data structures

6. HDFEOS Datablade
HDF-EOS Datablade components
will include:
Types
Routines: data inquiry functions,
subsetting functions as referred in HDFEOS library
Routines
HDFEOS indexing methods for sorting
and storing data
Tables
Tables containing HDF-EOS metadata
and data
Access
Methods
Client oriented code for data processing
Client
Code
DataBlade Module
New data types: Grid, Swath, Point

7. HDFEOS DataBlade
Benefits
Access cross granule information via SQL
Easy browsing
Improved performance with use of built-in index
Portability - data and functions packaged inside database
server
Ease of integration with other data types
INFORMIX-Universal
Server
Queries
Results

8. HDFEOS User Scenario
A user wishes to perform a correlation study between different physical
parameters for a specific geographical area.
example: Correlation between cloud amount and precipitation
User issues query to view all grid data objects that covers Bermuda.
The query returns all granule names, grid information (names,
dimensions, projection, fields etc.) matching the criteria.
User issues query to retrieve data of interest.
Query returns data of interest

9. Sample Scenario
select Grd.filename, Grd.name, Grd.projection, Grd.dimensions, Fld.fieldname
from HEOSgrid Grd, HEOSgdfield Fld
where ((Grd.filename = Fld.filename and Grd.objid = Fld.gridid) and
Contains(Grd, '(32, 70, 42, 60)');

10. User Scenario cont’d
Query to retrieve subset of data (“Precip” field)
select LatLonSubset(Fld, '(32, 70, 42, 60)')
from HEOSgdfield Fld
where Fld.filename = 'pathfinder_flat_month.8708.psg.hdfeos' and
Fld.gridname = ’SSMI'
and
Fld.fieldname = ’Precip';
Query to retrieve entire granule
execute HEOSretrv((granulename, outfile , location);

11. HDFEOS Datablade
Summary
Easy access and manipulation of HDF-EOS grid, swath, point data
types via SQL3
Data and the functions reside inside database for better
performance
Structural metadata search across granules by simple SQL
Only SQL knowledge required by novice USERS to access HDFEOS data
Database provides data reliability, security, portability, extensibility,
transaction, performance
Datablade provides flexibility to incorporate HDF data objects

12. HDFEOS User Scenario
A user wishes to perform a correlation study between different physical
parameters for a specific geographical area.
example: Correlation between cloud amount and precipitation
User issues query to view all grid data objects that covers Bermuda.
The query returns all granule names, grid information (names,
dimensions, projection, etc.) matching the criteria.
User issues query to view fieldnames from granules/grids of interest
Query returns fieldnames contained in the grid
User issues query to retrieve data of interest.
Query returns data of interest

13. Sample Scenario
select * from HEOSgrid Grd where Contains(Grd, '(32, 70, 42, 60)');

14. Scenario - select fields
Query to list all fieldnames contained in the specified grid objects
select filename, gridname, fieldname
from HEOSgdfield
where ((gridname = ‘SSMI’ and filename = ‘xxxx’) and
(gridname = ‘CloudAmt’ and filename = ‘yyyy’));
OR
select filename gridname fieldname

15. HDF-EOS search queries
To get summary of all filenames, their size and the number of
objects in each data file residing in the database:
select orgfile, size, numobj from HEOSfile;
To retrieve core, product specific, or archive metadata from
specific HDF-EOS data file:
select core-metadata, product-metadata from hdfeos where
orgfile=‘toms_monthly_498.HEOSfile’;