Raster datasets and raster catalogs in a geodatabase stored in Oracle

Raster datasets and raster catalogs in a geodatabase stored in Oracle
Release 9.3

Rasters in ArcCatalog

Raster tables in an Oracle DBMS

NOTE: Beginning with Oracle 11g, LONG RAW data types are no longer supported. Therefore, ESRI recommends you do not create new raster datasets using LONG RAW storage.

• Rasters stored in LONG RAW or BLOB format

• The business table
The business table is a DBMS table that stores attributes and is spatially enabled by adding a geometry footprint column. It delineates the area of the raster. In the example above, the business table is the WORLD_TIF table.
A business table with a raster column is a raster dataset or a raster catalog. A raster dataset can have only one business table row, while a raster catalog can have more than one. Information about the raster column is maintained in the RASTER_COLUMNS system table.
Information about all business tables, regardless of whether or not they have a spatial column or raster column, is maintained in the TABLE_REGISTRY system table.
• The feature table (f<layer_id>)
The feature table stores the geometry of the raster dataset. This table is identified by the number from the LAYER_ID column of the LAYERS table. The relationship between the business table and the feature table is managed through the Feature ID, or FID. This key, which is maintained by ArcSDE, is unique for the spatial column. In the example above, the feature table is F117.
• The spatial index table (s<layer_id>)
The spatial index table stores references to shapes based on a simple, regular grid. This table is identified by the number in the LAYER_ID column in the LAYERS table. In the World raster dataset example, the spatial index table is S117.
The spatial index contains an entry for each shape and grid cell combination to support spatial queries. When a spatial query is performed, the grid cells within the search area are identified and used to return a list of candidate pixels.
• Raster image tables
The actual raster images are stored in the following tables:
• SDE_AUX_<raster_column_ID>—The raster auxiliary table; stores the color map, statistics, and bit mask of the image
• SDE_BLK_<raster_column_ID>—The raster blocks table; stores the actual image data for each band of the image
• SDE_ BND_<raster_column_ID>—The raster band table; stores metadata about the bands of the image
• SDE_RAS_<raster_column_ID>—The raster description table; stores the description of the images within a raster column
ArcSDE geodatabases store raster bands in the raster band table. ArcSDE joins the raster band table to the raster table on the raster_id column. The raster band table's raster_id column is a foreign key reference to the raster table's raster_id primary key.
ArcSDE automatically stores any existing image metadata such as image statistics, color maps, or bit masks in the raster auxiliary table. The rasterband_id column of the raster auxiliary table is a foreign key reference to the primary key of the raster band's table. ArcSDE joins the two tables on this primary/foreign key reference when accessing a raster band's metadata.
The raster blocks table stores the pixels of each raster band. ArcSDE tiles the pixels into blocks according to a user-defined dimension. ArcSDE does not have a default dimension; however, applications that store raster data in ArcSDE geodatabases do. ArcToolbox and ArcCatalog, for example, use default raster block dimensions of 128 by 128 pixels per block. The dimensions of the raster block, along with the compression method if one is specified, determine the storage size of each raster block. You should select raster block dimensions that, combined with the compression method, allow each row of the raster block table to fit within an Oracle data block. For Oracle databases, storing raster data should be created with a 16 KB Oracle data block size.
The raster blocks table contains the rasterband_id column, which is a foreign key reference to the raster band table's rasterband_id primary key. These tables are joined together on the primary/foreign key reference when accessing the blocks of the raster bands.
The raster blocks table is populated according to a declining resolution pyramid. The height of the pyramid is determined by the number of levels, specified by the application. The application, such as ArcToolbox or ArcCatalog, may allow you to define the levels, may request that ArcSDE calculate them, or may offer both choices.
The pyramid begins at the base, or Level 0, which contains the original pixels of the image. The pyramid proceeds toward the apex by coalescing four pixels from the previous level into a single pixel at the current level. This process continues until ArcSDE reaches the apex, which may be automatically defined or user defined.
The additional levels of the pyramid increase the number of raster blocks by as much as one-third. However, since you can specify the number of levels, the size of the pyramid can be less. The first level of the pyramid will be 25 percent of the base. It should also be noted that the first level of the pyramid can be skipped; a factor that can greatly reduce the size of the pyramid.

When you build a pyramid, more pixels are created by progressively downsampling the previous level by a factor of two until the apex. As the application zooms out and the raster cells grow smaller than the resolution threshold, ArcSDE selects a higher level of the pyramid. The purpose of the pyramid is to optimize display performance.
The following are the table definitions for the raster tables:

NOTE: You will only have the raster tables in your geodatabase if you have raster data in the geodatabase.

SDE_AUX_<raster_column_ID>
The raster auxiliary table stores the image color map, image statistics, and the optional bit mask, which is used for image overlays and mosaicking.



Field name	Field type	Description
RASTERBAND_ID	NUMBER(38)	A number that represents a raster band; for example, a raster dataset with two raster bands would have two different values in this field—1 and 2 NOT NULL
TYPE	NUMBER(38)	Values include 2 = raster statistics 3 = color map 4 = coordinate transformation 5 = reserved for geodatabase 6 = miscellaneous NOT NULL
OBJECT	LONG RAW or BLOB	Contains the actual data, either a color map index, raster statistics, or coordinate transformation NOT NULL

SDE_BLK_<raster_column_ID>
The raster blocks table stores the image tiles.



Field name	Field type	Description
RASTERBAND_ID	NUMBER(38)	A number that represents a raster band; for example, a raster dataset with two raster bands would have two different values in this field—1 and 2 NOT NULL
RRD_FACTOR	NUMBER(38)	Pyramid level; pyramid levels begin at 0 and can increase from there NOT NULL
ROW_NBR	NUMBER(38)	Tile row number position NOT NULL
COL_NBR	NUMBER(38)	Column row number position NOT NULL
BLOCK_DATA	LONG RAW or BLOB	Pixel data stored in the tile NOT NULL

SDE_BND_<raster_column_id>
The raster band table stores information about the bands of the images. There is one record for each raster band.



Field name	Field type	Description
RASTERBAND_ID	NUMBER(38)	A number that represents a raster band; for example, a raster dataset with two raster bands would have two different values in this field—1 and 2 NOT NULL
SEQUENCE_NBR	NUMBER(38)	Sequence of the raster band within the raster dataset NOT NULL
RASTER_ID	NUMBER(38)	The unique identifier of the raster dataset; corresponds to the value in the raster column of the business table NOT NULL
NAME	VARCHAR2(65)	The optional raster band name
BAND_FLAGS	NUMBER(38)	A bit mask containing properties about the band NOT NULL
BAND_WIDTH	NUMBER(38)	The pixel width of the band NOT NULL
BAND_HEIGHT	NUMBER(38)	The pixel height of the band NOT NULL
BAND_TYPES	NUMBER(38)	A bit mask containing properties about the band NOT NULL
BLOCK_WIDTH	NUMBER(38)	The pixel width of a block NOT NULL
BLOCK_HEIGHT	NUMBER(38)	The pixel height of a block NOT NULL
BLOCK_ORIGIN_X	NUMBER(64)	The x-coordinate of the raster origin NOT NULL
BLOCK_ORIGIN_Y	NUMBER(64)	The y-coordinate of the raster origin NOT NULL
EMINX	NUMBER(64)	The minimum x-value of a raster band; with eminy, emaxx, and emaxy, defines the envelope of a raster band NOT NULL
EMINY	NUMBER(64)	The minimum y-value of a raster band; with eminx, emaxx, and emaxy, defines the envelope of a raster band NOT NULL
EMAXX	NUMBER(64)	The maximum x-value of a raster band; with eminx, eminy, and emaxy, defines the envelope of a raster band NOT NULL
EMAXY	NUMBER(64)	The maximum y-value in a raster band; with eminx, eminy, and emaxx, defines the envelope of a raster band NOT NULL
CDATE	NUMBER(38)	The creation date of the raster band NOT NULL
MDATE	NUMBER(38)	The last modification date of the raster band NOT NULL

SDE_RAS_<raster_column_id>
The raster description table stores the description of the images stored in a raster column.



Field name	Field type	Description
RASTER_ID	NUMBER(38)	The unique identifier of the raster dataset; corresponds to the value in the raster column of the business table NOT NULL
RASTER_FLAGS	NUMBER(38)	Reserved for future use
DESCRIPTION	VARCHAR2(65)	The description of the raster dataset

Raster catalogs and datasets are tracked in the system table GDB_RASTERCATALOGS. Like other types of data, raster catalogs and datasets are also tracked by name in the GDB_OBJECTCLASSES, LAYERS, and TABLE_REGISTRY tables. Columns of type raster are tracked in the COLUMN_REGISTRY and RASTER_COLUMNS table—there is one entry for every table containing a raster column. The number in the name of the raster side tables—2 in the example below—corresponds to the RASTER_COLUMN_ID value in the RASTER_COLUMNS table.
There can also be additional attribute tables as part of the raster dataset or raster catalog. There would only ever be one raster attribute table per raster dataset, but raster catalogs could have several such tables. The raster attribute tables are used to define attributes for particular raster cell values. See Raster dataset attribute tables for information on using these tables.
You can use the Build Raster Attribute tool of the Raster Properties toolset in the Raster toolset of the Data Management toolbox. See the topic Build Raster Attribute Table (Data Management) for details on this tool.
For raster datasets, the table name is in the format SDE_VAT_<raster_column_ID>. For raster catalogs, the table name is in the format SDE_VAT_<raster_column_ID>_<Object_ID>.
The link below will open a PDF showing the dataset tables and system tables of the WORLD_TIF raster dataset stored in LONG RAW. Dashed lines indicate implicit relationships between tables; solid lines indicate explicitly defined relationships. You will need Adobe Acrobat Reader to open this file.
Oracle raster dataset diagram
The owner fields in the GDB_OBJECTCLASSES, TABLE_REGISTRY, COLUMN_REGISTRY, RASTER_COLUMNS and LAYERS table all contain the same value, but to keep the diagram from being too cluttered, the implicit relationship between these fields is not shown.
Given the nature of raster data, databases that contain rasters tend to be quite large. Raster datasets and raster catalogs are rarely less than a few gigabytes (GB) and can occupy several terabytes (TB) within your DBMS. Coping with the large size of raster data can, therefore, be a challenge. For recommendations and examples of how to manage your raster data in an ArcSDE geodatabase, see the white paper Raster data in ArcSDE, which can be downloaded from the ArcSDE support site at support.esri.com.
• Rasters stored in Oracle GeoRaster format
Rasters stored in Oracle GeoRaster format have a business table with a column of type MDSYS.GEORASTER. This information is tracked in the Oracle metadata schema. The MDSYS.GEORASTER column will contain components similar to the following:



Name	Example component value
RASTER	SDO_GEORASTER
RASTERTYPE	20001
SPATIALEXTENT	SDO_GEOMETRY
SDO_GTYPE	2003
SDO_SRID	NULL
SDO_POINT	NULL
SDE_ELEM_INFO	SDO_ELEM_INFO_ARRAY(1,1003,3)
SDO_ORDINATES	SDO_ORDINATE(0,0,0256,256)
RASTERDATATABLE	'SDE_RDT_1897'
RASTERID	2
METADATA	XMLTYPE(<georasterMetadata xmlns="http://xmlns.oracle.com/spatial/georaster"> <objectI)

NOTE: The metadata column is very long, so to view it with SQL*Plus, you must increase both the LONGSIZE and PAGESIZE SQL*Plus environments and query it directly as follows:

set LONG 20000
set PAGESIZE 500



The pixel data for each SDO_GEORASTER column is stored in a separate raster data table. The SDO_GEORASTER data tables created by ArcSDE are named SDE_RDT_<raster_column_id> where <rastercolumn_id> is the raster_column_id field in the RASTER_COLUMN table, which uniquely identifies that raster column within the ArcSDE metadata. ArcSDE uses the BLK_STORAGE DBTUNE storage parameter to control the Oracle storage parameters of the SDE_RDT_<rastercolumn_id> table. For a description of this table and its fields, consult chapter 1 of the Oracle Spatial GeoRaster documentation provided by Oracle.
SDE_RDT_<raster_column_id>



Field name	Field type
RASTERID	NUMBER
PYRAMIDLEVEL	NUMBER
BANDBLOCKNUMBER	NUMBER
ROWBLOCKNUMBER	NUMBER
COLUMNBLOCKNUMBER	NUMBER
BLOCKMBR	MDSYS.SDO_GEOMETRY
RASTERBLOCK	BLOB

Click the following link to view a PDF diagram of a raster dataset using Oracle GeoRaster storage:
Oracle GeoRaster raster dataset diagram

Rasters in an XML document

<esri:Workspace xmlns:esri="http://www.esri.com/schemas/ArcGIS/9.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <WorkspaceDefinition xsi:type="esri:WorkspaceDefinition">
   <WorkspaceType>esriRemoteDatabaseWorkspace</WorkspaceType> 
   <Version>sde.DEFAULT</Version> 
   <Domains xsi:type="esri:ArrayOfDomain" /> 
   <DatasetDefinitions xsi:type="esri:ArrayOfDataElement">
     <DataElement xsi:type="esri:DERasterDataset">
       <CatalogPath>/V=sde.DEFAULT/RD=GDB.world_TIF</CatalogPath> 
       <Name>GDB.world_TIF</Name> 
       <Children xsi:type="esri:ArrayOfDataElement">
          <DataElement xsi:type="esri:DERasterBand">
            <CatalogPath>/V=sde.DEFAULT/RD=GDB.world_TIF/RB=Band_1</CatalogPath> 
            <Name>Band_1</Name> 
            <DatasetType>esriDTRasterBand</DatasetType> 
            <DSID>-1</DSID> 
            <Versioned>false</Versioned> 
            <CanVersion>false</CanVersion> 
            <HasOID>true</HasOID> 
            <OIDFieldName>ObjectID</OIDFieldName> 
            <Fields xsi:type="esri:Fields">
              <FieldArray xsi:type="esri:ArrayOfField">
                <Field xsi:type="esri:Field">
                    <Name>ObjectID</Name> 
                    <Type>esriFieldTypeOID</Type> 
                    <IsNullable>false</IsNullable> 
                    <Length>4</Length> 
                    <Precision>0</Precision> 
                    <Scale>0</Scale> 
                    <Required>true</Required> 
                    <Editable>false</Editable> 
                </Field>
                <Field xsi:type="esri:Field">
                    <Name>Value</Name> 
                    <Type>esriFieldTypeInteger</Type> 
                    <IsNullable>true</IsNullable> 
                    <Length>0</Length> 
                    <Precision>0</Precision> 
                    <Scale>0</Scale> 
               </Field>
               <Field xsi:type="esri:Field">
                    <Name>Count</Name> 
                    <Type>esriFieldTypeInteger</Type> 
                    <IsNullable>true</IsNullable> 
                    <Length>0</Length> 
                    <Precision>0</Precision> 
                    <Scale>0</Scale> 
               </Field>
             </FieldArray>
         </Fields>
         <Indexes xsi:type="esri:Indexes">
           <IndexArray xsi:type="esri:ArrayOfIndex" /> 
         </Indexes>
         <IsInteger>true</IsInteger> 
         <MeanCellHeight>0.175996089009095</MeanCellHeight> 
         <MeanCellWidth>0.176000337991447</MeanCellWidth> 
         <Height>1024</Height> 
         <Width>2048</Width> 
         <PixelType>U8</PixelType> 
         <PrimaryField>1</PrimaryField> 
         <TableType>esriRasterTableValue</TableType> 
         <Extent xsi:type="esri:EnvelopeN">
            <XMin>-179.906382261841</XMin> 
            <YMin>-90.1303147686327</YMin> 
            <XMax>180.542309944643</XMax> 
            <YMax>90.089680376681</YMax> 
            <SpatialReference xsi:type="esri:GeographicCoordinateSystem">
   <WKT>GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]</WKT> 
          <XOrigin>-400</XOrigin> 
          <YOrigin>-400</YOrigin> 
          <XYScale>11258999068426.2</XYScale> 
          <ZOrigin>0</ZOrigin> 
          <ZScale>1</ZScale> 
          <MOrigin>0</MOrigin> 
          <MScale>1</MScale> 
          <XYTolerance>8.98315284119521E-09</XYTolerance> 
          <ZTolerance>2</ZTolerance> 
          <MTolerance>2</MTolerance> 
          <HighPrecision>true</HighPrecision> 
          <LeftLongitude>-180</LeftLongitude> 
         </SpatialReference>
        </Extent>
      </Data>
    </DatasetData>
   </WorkspaceData>
</esri:Workspace>