For data discovery

Open Geospatial Consortium（OGC）Catalogue Service for Web profile（CSW）will be used for all data sources.For data access to traditional sensor data systems

the OGC Web Coverage Service（WCS）

OGC Web Feature Service（WFS）

and Open-source Project for a Network Data Access Protocol（OPeNDAP）will be used.For connection to web-enabled sensors

OGC Sensor Web Enablement（SWE）protocols（e.g.

Sensor Observation Service

SensorML）will be used.In order to find the sensor

clusters of sensors or data in a heterogeneous distributed en- vironment with some special criteria

such as coincidence of time

space

or scale

an architecture of retrieval geospatial sensor data based on the integration of CSW with sensor observation service（SOS）is put forward

which includes distrib- uted geospatial sensor observation service（D

S

OS）

geospatial catalogue service based on ebXML Registry Information Model（ebRIM）

SOS register and search middleware and geospatial sensor service portal. D

S

OS is the collection of Sensor Observation Service（SOS）based on distributed network environment

packaged into a Web service and deployed into a web container

an API is provided to manage deployed sensors and retrieve sensor data and specifically observation data.It retrieves sensor properties and sensor data with three core operations:GetCa- pabilities

DescribeSensor

and GetObservation.The"GetCapabilities"operation can get the metadata for specified serv- ice instances:identifier

provider

operation metadata

filter capabilities

and contents.The"DescribeSensor"operation can get the detailed sensor description information encoded using a sensor information model（SensorML or TML）.The"GetObservation"operation can get the observation or survey data encoded by the O

&

M information model.It has two types of users:One is the SOS provider

who can supply sensor observation and survey data to SOS;the other is the sensor data consumer.In this paper

the sensor data consumers are the geospatial catalogue service and the SOS registry middle- ware. Geospatial catalogue service based on ebRIM is the access component of the SOS and implements with ebRIM profile of CSW.This service allows entities to be registered and discovered by data consumers.It supports the registry and discov- ery of services

datasets

coverages

features

and service chain.The external interface follows the OGC CSW2.0 stand- ard

which supports three types of interface:OGC

S

ervice

Discovery

and Manager.The OGC

S

ervice interface is the getCapabilities operation

providing a description of the capabilities for catalogue service and also providing related XML documents.The Discovery interface provides three operations by which clients can discover and obtain the information reg- istered in the catalogue service database.The Manager interface allows users to use the"push"or"pull"mode to update catalogue content. SOS registry and search middleware is a coordinator in the system

which is responsible for SOS search

capability and observation data registry.It extracts information and generates records for the sensor data granules.Each record in the registry contains SOS basic information

SOS capability information

or SOS observation data.Sensor data granules are auto-harvested

real time sensor data granule records are registered

and timing of SOS information is updated through reg- istry middleware.Management and query of registry information is implemented by space-time index. Geospatial sensor service portal is the user access point of the system

it is implemented using Java portal technology

the portal carries out the following functions:user authorization service

user signing service and SOS searching presenta- tion service. The content and sequence of SOS basic service information

SOS Contents and SOS observation data register approa- ches are presented.The deep time-space search and large amount of observation data management is described.A visual search based on Google map

adjoining sheet table and meta index of register information is presented. The prototype system is designed and implemented by OGC CSW specification and SWE SOS standard

the following functions are included:SOS service discovery

SOS basic information registry

SOS capability information registry

SOS observation data registry

SOS registry information management

and SOS registry information query.The EO-1 SOS regis- ter is tested

including one SOS record

ten SOS capabilities content records and 2420 WCSLayer observation records in a specified time. The experimental result shows that the approach has three advantages in SOS search

management and integration with other OGC data service than that of the mentioned geospatial sensor web enabled prototype system.SOS service infor- mation is registered as a"ServiceType"and SOS capability content registered as a"DataType".They could be discovered by a CSW"GetRecords"operation;SOS observation data can be registered as"WCSLayer"or"WFSLayer"data gran- ule.They can also be discovered by a CSW"GetRecords"operation and served through OGC WCS or WFS servers respec- tively

depending upon how they are registered.Through Sensor Web data registry middleware

the sensor observations can be integrated with other OGC data services.Hence

the register middleware method reduces waiting time when access- ing real time observational data in a sensor Web based emergency response system. Access to the sensor web system is by SPS and SOS.The next step is to study how to provide an open self-adaptive geospatial data service by harmonizing SOS

SPS

WCS and WFS.