Development of Java plug-in for Geoserver to read Oracle GeoRaster by WAnDq8iy

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									Development of Java plug-in for Geoserver to
       read Oracle GeoRaster Data

                         Authors

                         Baskar Dhanapal
                         CoreLogic
                         Bangalore, India


                         Perumal Chinnuswamy
                         CoreLogic
                         Bangalore, India


                         Bruce E.Thelen
                         CoreLogic
                         Austin, USA
                     Agenda
•   About CoreLogic
•   Need and Scope
•   Technology and tools used
•   Architecture
•   Existing Approach
•   Plug-in Development
•   Benefits of this plug-in
•   Screen shots
•   Conclusion
                       About CoreLogic
• Launched from The First American Corporation, CoreLogic is a leading
  provider of consumer, financial and property information, analytics and
  services to business and government.
• We have more than one million users who rely on our data.
• We have most comprehensive repository of public, contributory and
  proprietary data in the United States like mortgage information, parcel
  and geospatial data; motor vehicle records, criminal background records;
  national coverage eviction information, payday lending records, credit
  information, and tax records.
• Working with over 40,000 clients in the public and private sectors has
  given us a vast storehouse of real-world experience to draw upon in
  helping you create effective solutions that target your unique needs
     Need and Scope of this plug-in
• Geoserver reads and supports all featureType data like shapefile, point,
  polygon etc. from local file system as well as from oracle spatial database.
  It also reads and support raster images from local file system only. It does
  not support to read GeoRaster data from oracle spatial. This plug-in helps
  Geoserver to read GeoRaster data from database.
• To create separate standalone plug-in for Geoserver to read Oracle
  GeoRaster data
• To include all basic functionalities like zoom-in, zoom-out and panning to
  GeoRaster data
• It should follow all the rules that GeoTools community described to create
  plug-in for GeoServer.
       Technology and Tools used
•   Windows environment
•   Java 1.5
•   GeoTools API version 2.7-SNAPSHOT
•   Oracle Spatial Queries
•   Maven
•   GeoServer
                        Architecture
• Client application can be any web
  client which has capability to
  send http request.
• Client application can query
  Geoserver using WMS request to
  get required GeoRaster data.
• GeoServer in turn query
  GeoRaster data which is stored in
  Oracle spatial database using the
  GeoRaster plug-in deployed in
  GeoServer.
• User can view GeoRaster data in
  Openlayers window and also in
  any format like GIF,JPEG,PNG.
                                 Oracle GeoRaster
•   The core of Oracle Spatial GeoRaster is the
    physical schema designed to facilitate storing
    and managing raster or grid-based data inside
    the database
•   A GeoRaster table is any user-defined table,
    which has at least one data column of type
    SDO_GEORASTER
•   SDO_GEORASTER objects include metadata and
    information about how to retrieve GeoRaster
    cell data which is stored in another user-defined
    table called a Raster Data Table, which is an
    object table of type SDO_RASTER.
•   The SDO_RASTER type includes a BLOB column
    called RASTERBLOCK, which stores the real
    raster blocks
•   Other information associated with the
    GeoRaster objects can be stored in separate
    columns or tables, such as a Value Attribute
    Table (VAT).
•   The relationship between a GeoRaster object
    and its raster data table is automatically
    managed by GeoRaster itself internally using a
    database dictionary
                                Geoserver
•   The GeoServer application is
    comprised of a series of modules
•   At runtime, a module can make use
    of Spring to obtain classes providing
    services from other modules. This
    ability to "plug-in" additional
    functionality forms the basis for
    GeoServers extension mechanism
•   Web Map Service (WMS) provides a
    simple HTTP interface for requesting
    geo-registered map images from one
    or more distributed geospatial
    databases
•   A WMS request defines the
    geographic layer(s) and area of
    interest to be processed. The
    response to the request is one or
    more geo-registered map images
    (returned as JPEG, PNG, etc)
                             GeoTools
• GeoTools is a free software GIS
  toolkit for developing standards
  compliant solutions. It provides
  an implementation of Open
  Geospatial Consortium (OGC)
  specifications as they are
  developed
• It is written in Java and currently
  is under active development. It is
  used by GeoServer and UDig
  projects
• GeoTools library includes lots of
  plug-ins to support different data
  formats with different coordinate
  reference system
Existing GeoRaster Support
•     Recently, GeoRaster support has been added in GeoTools 2.6.4 version. It is
      developed as an extension of “ImageMosaic-JDBC” plug-in
•     This plug-in takes one xml config file as input that contains all information
      needed to query GeoRaster data

Flaws of Existing approach

1.    It does not mosaic georaster data if the GeoRaster table has ‘n’ number of rows.
      This feature supports to retrieve only one row of data at a time.
2.    It does not work with other layers.
3.    It is not separate standalone plug-in. It is an extension of “ImageMosaic-JDBC”
      plug-in.
4.    User has to mention the co-ordinate reference systems (i.e EPSG) in the config
      file
5.    User has to know “GEORASTER” field name in GeoRaster table and name of the
      “RASTER DATA TABLE”. All these things have to be mention in config file
                   Plug-in Development
•     First we need to store the GeoRaster data in Oracle spatial database
•     we need to find the way how we can make Geoserver to recognize our code as a plug-in.
    –       To do this we need GeoTools support. Geoserver internally depends on GeoTools
            library for all data manipulation. GeoTools provides few interfaces and class that
            needs to be implemented and extended to develop new plug-in.
    –       Geoserver handles two types of data i.e Vector and Raster data. GeoTools has
            separate hierarchy structure of class to handle these types of data.
    –       Since GeoRaster is raster type of data, we concern about the classes required to
            handle raster data. Following are the interfaces and classes that needs to be
            implemented and extended to create new plug-in.

         1. org.geotools.coverage.grid.io.GridFormatFactorySpi (interface)
         2. org.opengis.coverage.grid.Format (interaface)
         3. org.geotools.coverage.grid.io.AbstractGridFormat (class)
            Plug-in Development cont.,
•    We build the source code using Maven, a build tool and created jar file. Finally, we placed the
     resultant jar in lib directory of Geoserver.
•    Next time, whenever Geoserver starts, it recognizes the jar as a plug-in and it list
     GeoRaster as valid data source option in Geoserver
•    This plug-in does not depend on any licensed version jars.


• Input Configuration file format
      <datastore >
      <coverage>coverage_Name</ coverage >
      <rastertable>Georaster_Table_Name</rastertable>
       <server>DB Server IP</server>
       <dbname>DB NAME</dbname>
       <port>port</port>
       <username>username</username>
      <password>password</password>
    </datastore>
          Plug-in Development cont.,
•   <datastore>  Denotes the start of GeoRaster configuration details.
•   <coverage>  User defined name for layer
•   <rastertable>  Name of Georaster table which holds tiles of GeoRaster data
•   <server>  Database server address
•   <port>  Database port
•   <username>  login id
•   <password>  password

The configuration files has very few limited information needed to process
GeoRaster data.
           Benefits of this plug-in

• It’s a separate plug-in developed to read GeoRaster data
  based on “ImageMosaic-JDBC” plug-in.
• It mosaic “n” number of GeoRaster data from a table.
• It works with other layers.
• It needs few information about GeoRaster table in
  configuration file.
ScreenShots
Screenshots cont.,
            Screenshots cont.,
• Coordinate Reference
  systems and Bounding
  boxes are calculated
  automatically by the
  plug-in.
Screenshots cont.,
Screenshots cont.,
Screenshots cont.,
                     Conclusion

• This plug-in helps people who works with GeoRaster data.
• Need to check-in the code public repository.
• Getting support from various developer around the world by
  giving the code to them directly.
• Contact : dbaskar@corelogic.com for more information.
    Thank you….


Questions if any……………..?

								
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