Service Metadata Product Metadata
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Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.
o the geographical coverage of the acquired data;
o the ground station receiving the satellite downlink;
o other attributes depending on the type of sensor:
o for radar sensors possible relevant attributes are: polarization, Doppler
frequency, swath identifier; o
for optical sensors possible relevant attributes are: cloud coverage, the illumination angles;
o for atmospheric sensors possible specific attributes are: vertical coverage,
specy; From user point of view the main characteristic of Earth Observation products is their
geographical coverage and then, because GML provides a rich set of definitions for representing geographic objects, the representation of Earth Observation products is
performed through GML application schemas.
Earth observation products are modelled with the EarthObservationProductType type which is an extension of GML AbstractFeatureType type. Because different product
types derived by different type of sensors have different set of specific attributes, then the following approach has been followed:
o a namespace including definitions common to all sensors has been defined:
eop o
a separated namespace for each class of sensor has been defined: o
sar for radar sensors
o
opt for optical sensors
o
atm for atmospheric sensors
o other namespaces can be defined for other classes of sensors
o additional specific namespaces can be defined on top of previous ones.
The EarthObservationProductType is defined in each namespace by extending the definition in the parent namespace leading to this hierarchy:
Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.
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Namespaces for
radar missions
Namespaces for
optical missions
Namespaces for
atmospheric products
eop.xsd sar.xsd
opt.xsd atm.xsd
gml
Gen eri
c an
d ge
om et
ric
ca talo
gu e
m et
ad at
a Cat
al ogu
e m
et ada
ta
fo r E
ar th
O bs
erv at
ion Cat
al ogu
e m
et ada
ta
fo r s
pec ific
E O
m iss
ion ty
pe
Figure 3 : EarthObservationProduct type hierarchy.
The ―eop‖ metadata element names have been harmonized with ISO 19115 ISO 19139 schemas and ISO 19115 Part II draft as far as possible. The catalogue profile and GML
application schemas allows extension of this layered structure in order to complement the optical layer for a specific atmospheric mission, which would require additional
mission specific metadata or queryables.
Because a Catalogue compliant with this definition can return different EarthObservationProduct element format depending on the supported schema, then the
catalogue allows the clients to get first the list of supported schemas either eop, opt, sar, or other ones defined on them and then access the metadata at the level in the hierarchy
that best fit their needs when the data is retrieved.