Creating data delivery services from catalogue searches

1
Creating data delivery services from catalogue
searches

• Dr Matt Pritchard
• NERC Earth Observation Data Centre (NEODC)
• http//www.neodc.rl.ac.uk
• CCLRC Rutherford Appleton Laboratory, UK

2
Introduction

• QMASS
• NERC Earth Observation Data Centre (NEODC)
• NEODC LANDSAT service
• NEODC ATSR service

3
Talk outline

• Overview of services
• Development details
• Search and present in SSE services
• Spatial searching
• Future plans
• Comments

4
Overview of services

• NEODC LANDSAT

5
LANDSAT Service
6
LANDSAT Service
7
LANDSAT Service
8
LANDSAT Service
9
LANDSAT Service
10
Overview of services

• NEODC ATSR

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ATSR Service
12
ATSR Service
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ATSR Service
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ATSR Service
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ATSR Service
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ATSR Service
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ATSR Service
18
Talk outline

• Overview of services
• Development details
• Search and present in SSE services
• Spatial searching
• Future plans
• Comments

19
Search and Present in SSE services
NEODC Metadata catalogue
SearchInputMsg
SearchOutputMsg
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Search and Present in SSE services

• Search
• processSearchInputMsg sent from Portal
• Encodes coordinates, collectionId,
• Create db connection

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Search and Present in SSE services

• Search
• Convert parameters to SQL string
• summary presentation format
• Stylesheet Search2SQL.xsl

processSearchInputMsg
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Search and Present in SSE services

• Search
• Query execution

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Search and Present in SSE services

• Search
• Search script invoked to handle result
• Summary presentation -gt summaryScript.xml
• summary / brief / browse / full
• Creates processSearchOutputMsg

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Search and Present in SSE services

• Search
• GML footprints for display on Portal AOI tool
• processSearchOutputMsg
• Catalogue2GML.xsl
• GML file

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Search and Present in SSE services

• Present
• Single item, more detail
• Full presentation format -gt fullPresentScript.xml

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Talk outline

• Overview of services
• Development details
• Search and present in SSE services
• Spatial searching
• Future plans
• Comments

27
Spatial searching

• Spatial databases
• Geometric datatypes
• geometry

CREATE TABLE mytable ( ... myfield
geometry, ... ) INSERT INTO mytable (myfield)
VALUES( 'SRID4326POLYGON(( 38.49
-3.37, 40.68 -3.37, 40.68 -5.28, 38.49
-5.28, 38.49 -3.37 )) )
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Spatial searching (PostGIS)

• Geometric comparison operators
• (overlaps)
• _at_ (contains)

select myfield from mytable where myfield
GeometryFromText('BOX3D(30 0, 40
-10)'box3d,4326) SRID4326POLYGON((38.4958795
-3.376287,40.6831798 -3.374955,40.6874065
-5.2848047,38.4946129 -5.2868938,38.4958795
-3.376287)) (1 row)
select myfield from mytable where dsgpolyo
GeometryFromText('POLYGON((0 0, 40 0, 40 -10, 0
-10, 0 0))',4326) SRID4326POLYGON((38.4958795
-3.376287,40.6831798 -3.374955,40.6874065
-5.2848047,38.4946129 -5.2868938,38.4958795
-3.376287)) (1 row)
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Spatial searching (PostGIS)

• Geometric functions
• xmin(geometry)
• transform(geometry, srid)

select xmin(myfield), ymin(myfield),
xmax(myfield), ymax(myfield) from mytable where
myfield GeometryFromText('BOX3D(30 0, 40
-10)'box3d,4326) xmin ymin
xmax ymax 38.4946129 -5.2868938
40.6874065 -3.374955 (1 row)
select xmin(transform(myfield,27700)) from
mytable where myfield GeometryFromText('BOX3D(3
0 0, 40 -10)'box3d,4326)
xmin 5307661.95830263 (1 row)
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Spatial searching (PostGIS)

• Longitude180 problem

Polygon C westbc 175 eastbc -175 northbc
75 southbc 70 (westbc gt eastbc) Blue
AOI westbc -10 eastbc 10 northbc 75 southbc
70
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Spatial searching (PostGIS)

• Longitude180 problem
• False positive for polygon that does not exist

PostGIS http//postgis.refractions.net PostgreSQL
http//www.postgresql.org
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Spatial searching

• PgSphere
• PostgreSQL extension
• Spherical geometry
• spoly

CREATE TABLE myTable ( ... myField spoly,
... ) INSERT INTO mytable (spoly) VALUES( '
(160d,75d), (170d,75d), (170d,70d), (160d
,70d), (160d,75d) ')
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Spatial searching (PgSphere)

• Geometric comparison operators
• (overlaps)
• _at_ (contains)

select id, myfield from mytable where myfield
sbox '((165d,65d),(173d,73d))' id myfield A
"A""(2.792 , 1.308),(2.967 , 1.308),(2.967 ,
1.221),(2.792 , 1.221)" (1 row)
select id FROM mytable WHERE myfield _at_ sbox
'((160d,65d),(-170d,76d))' id A C (2 rows)
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Spatial searching (PgSphere)

• Spherical geometry
• Correct result
• PgSphere
• http//www.pgastro.org/cgi-bin/wiki.pl?pgSphere

select id FROM mytable WHERE sbox
'((-10d,70d),(10d,75d))' p id (0 rows)
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Talk outline

• Overview of services
• Development details
• Search and present in SSE services
• Spatial searching
• Future plans
• Comments

36
Future plans

• Future plans
• ATSR -gt AATSR
• Airborne geocorrection
• NEXTMap DEM
• User rights
• NEODC account login
• Other methods (x509 certificates?)

37
Talk outline

• Overview of services
• Development details
• Search and present in SSE services
• Spatial searching
• Future plans
• Comments

38
Comments

• TOOLBOX
• XML scripting language
• Context in which each tag will/will not work
• Script schema?
• Jelly XML?
• Portal
• Upgrades
• Notice of downtime / essential upgrades
• Existing / future services
• Backwards compatibility
• Security
• User rights management