After you enable GeoRaster for all schemas that will use the feature, create the GeoRaster objects, load the data, and validate the GeoRaster objects, you can perform the remaining operations in any order, depending on your application needs. You may also be able to skip certain operations.
Some operations can be performed using SQL, and some operations must be performed using PL/SQL blocks. You must update the GeoRaster object after you insert, update, reformat, compress, decompress, or delete the metadata or cell data of the GeoRaster object and before you commit the changes (see Updating GeoRaster Objects Before Committing). For some examples of these operations, see the demo files described in GeoRaster PL/SQL and Java Demo Files and the examples in SDO_GEOR Package Reference.
See also the operations in GeoRaster Data Query and Manipulation.
Other chapters in this book cover advanced topics (Raster Algebra and Analytics and Image Processing and Virtual Mosaic), and provide detailed reference information about GeoRaster PL/SQL packages (SDO_GEOR Package Reference, SDO_GEOR_ADMIN Package Reference, SDO_GEOR_AGGR Package Reference, SDO_GEOR_RA Package Reference, and SDO_GEOR_UTL Package Reference).
3.1 Enabling GeoRaster at the Schema Level
GeoRaster must be enabled for each database schema that will use the GeoRaster feature.
By default, the GeoRaster feature is disabled after the Oracle Spatial and Graph is initially installed. GeoRaster can be enabled only within the scope of a schema (that is, not for the entire database), and it must be enabled for each schema that will use the GeoRaster feature.
To enable GeoRaster, follow these steps for each schema for which GeoRaster will be enabled:
- Connect to the database as the user for that schema. For example:
- Enter the following statement:
- Verify that GeoRaster is now enabled by checking that the following statement returns
SELECT sdo_geor_admin.isGeoRasterEnabled FROM DUAL;
- Ensure that the user for this schema has the CREATE TRIGGER privilege (which is required for GeoRaster to work properly). If the user does not have the CREATE TRIGGER privilege (or if you do not know), connect as a DBA user and grant the user that privilege. For example:
CONNECT / AS SYSDBA GRANT create trigger TO scott;
If a GeoRaster table has been created and populated with data, then after a database upgrade, GeoRaster is automatically enabled for that table’s schema, and you do not need to re-enable GeoRaster for the schema. (Just ensure that the CREATE TABLE privilege is granted to the user.)
3.2 Adding Data Files and Temporary Tablespaces for GeoRaster Users
A GeoRaster database is typically very large. For storage and performance reasons, a database schema should use one or more user tablespaces for GeoRaster data storage (avoid using the system tablespace for storing GeoRaster data), and you should add data files to the tablespaces appropriately. If Oracle Automatic Storage Management (Oracle ASM) or a bigfile tablespace is not being used, you should create many data files for each tablespace and distribute the data files on different disks if possible. You also should create data files or alter existing data files, so that they automatically increase in size when more space is needed in the database.
A GeoRaster table can contain a large (potentially almost unlimited) number of GeoRaster objects. A raster data table (RDT) should be used to contain the raster blocks of a limited number of GeoRaster objects, depending on the size of the rasters. In contrast with GeoRaster tables, an RDT should not grow too large, unless partitioning is to be applied. Also, RDTs can be created on different tablespaces, so that the raster blocks are distributed to different disks. (See also Creating the GeoRaster Table and Raster Data Tables.)
A GeoRaster database may use a temporary tablespace for some operations. When compression is involved in GeoRaster operations, particularly for large scale mosaicking operations, some temporary spaces are needed to store intermediate compressed or uncompressed data. If the GeoRaster user does not have a temporary tablespace, the database system temporary tablespace is used. This is not efficient and may slow down the mosaicking and other operations. Therefore, you should always create temporary tablespaces for GeoRaster users. For example:
CONNECT system/<password>; CREATE TEMPORARY TABLESPACE geor_temp TEMPFILE 'geor_temp_1.f' SIZE 1G AUTOEXTEND ON; ALTER USER <georaster_user> TEMPORARY TABLESPACE geor_temp;
In general, the amount of temporary space needed is limited. However, for large scale mosaicking, if the result is to be compressed, the temporary space needed is equal to the uncompressed image size of the result. Therefore, specify
AUTOEXTEND ON when you create temporary tablespaces for GeoRaster users.
3.3 Creating the GeoRaster Table and Raster Data Tables
Before you can work with GeoRaster objects, you must create a GeoRaster table and one or more raster data tables, if they do not already exist.
3.3.1 Creating a GeoRaster Table
A GeoRaster table is any table that includes at least one column of type SDO_GEORASTER. The column can be an attribute column of another user-defined object type. Example 3-1 creates a GeoRaster table named CITY_IMAGES, which contains a column named IMAGE for storing GeoRaster objects.
Example 3-1 Creating a GeoRaster Table for City Images
CREATE TABLE city_images (image_id NUMBER PRIMARY KEY, image_description VARCHAR2(50), image SDO_GEORASTER);
For more information about GeoRaster tables, see GeoRaster Physical Storage.
3.3.2 Creating Raster Data Tables
After creating a GeoRaster table, you should create one or more raster data tables (RDTs) to be used with the objects in the GeoRaster table. You can create a raster data table as an object table or as a relational table. You should use the LOB storage format SecureFiles LOBs (SecureFiles) when creating RDTs. Using SecureFiles significantly improves the performance of GeoRaster operations, compared to using the original LOB storage paradigm BasicFiles LOBS (BasicFiles).
Example 3-2 creates a raster data table using SecureFiles. The RDT will be used to store all raster blocks of one or many GeoRaster objects in the CITY_IMAGES table or other GeoRaster tables. (The association between a GeoRaster object and a raster data table is not made until you create a GeoRaster object, as explained in Creating New GeoRaster Objects.)
Example 3-2 Creating a Raster Data Table Using SecureFiles
CREATE TABLE city_images_rdt OF SDO_RASTER (PRIMARY KEY (rasterID, pyramidLevel, bandBlockNumber, rowBlockNumber, columnBlockNumber)) TABLESPACE im_tbs_2 LOB(rasterBlock) STORE AS SECUREFILE (CACHE);
Example 3-3 Creating a Raster Data Table (Relational) Using SecureFiles
CREATE TABLE city_images_rdt (rasterID NUMBER, pyramidLevel NUMBER, bandBlockNumber NUMBER, rowBlockNumber NUMBER, columnBlockNumber NUMBER, blockMBR SDO_GEOMETRY, rasterBlock BLOB, CONSTRAINT pkey PRIMARY KEY (rasterId, pyramidLevel, bandBlockNumber, rowBlockNumber, columnBlockNumber)) LOB (rasterblock) STORE AS SECUREFILE(cache);
The CREATE TABLE statement for a raster data table must include the following clause (which is included in the preceding examples):
(PRIMARY KEY (rasterID, pyramidLevel, bandBlockNumber, rowBlockNumber, columnBlockNumber))
This PRIMARY KEY clause creates a B-tree index on the raster data table, and this index is essential for optimal query performance.
When you use BasicFiles, you can specify a larger CHUNK size (16 or 32 KB) for the LOB storage to improve performance. With SecureFiles, there is no need to specify the CHUNK size parameter, and there are few other storage parameters to consider. Raster data tables using SecureFiles LOBs must be created in a tablespace with the automatic segment space management option. For information about using Oracle SecureFiles and performance considerations for BasicFiles LOBs, see Oracle Database SecureFiles and Large Objects Developer's Guide.
For reference information about creating tables, including specifying LOB storage, see the section about the CREATE TABLE statement in Oracle Database SQL Language Reference.
For more information about the keywords and options when creating a raster data table, see Raster Data Table.
3.3.3 GeoRaster DML Trigger
To ensure the consistency and integrity of internal GeoRaster tables and data structures, GeoRaster automatically creates a unique DML trigger for each GeoRaster column whenever a user creates a GeoRaster table (that is, a table with at least one GeoRaster column), with the following exception: if you use the ALTER TABLE statement to add one or more GeoRaster columns, you must call the SDO_GEOR_UTL.createDMLTrigger procedure to create the DML trigger on each added GeoRaster column. In some scenarios, such as a database upgrade or a data migration, you can call the SDO_GEOR_UTL.recreateDMLTriggers procedure to re-create the DML triggers on all GeoRaster columns.
The trigger is fired after each of the following data manipulation language (DML) operations affecting a GeoRaster object: insertion of a row, update of a GeoRaster object, and deletion of a row.
GeoRaster automatically performs the following actions when the trigger is fired:
After an insert operation, the trigger inserts a row with the GeoRaster table name, GeoRaster column name, raster data table name, and
rasterIDvalue into the USER_SDO_GEOR_SYSDATA view (described in GeoRaster System Data Views (xxx_SDO_GEOR_SYSDATA)). If an identical entry already exists, an exception is raised.
After an update operation, if the new GeoRaster object is null or empty, the trigger deletes the old GeoRaster object. If there is no entry in the USER_SDO_GEOR_SYSDATA view for the old GeoRaster object (that is, if the old GeoRaster object is null), the trigger inserts a row into that view for the new GeoRaster object. If there is an entry in the USER_SDO_GEOR_SYSDATA view for the old GeoRaster object, the trigger updates the information to reflect the new GeoRaster object.
After a delete operation, the trigger deletes raster data blocks for the GeoRaster object in its raster data table, and it deletes the row in the USER_SDO_GEOR_SYSDATA view for the GeoRaster object.
3.4 Creating New GeoRaster Objects
Before you can store a GeoRaster image in a GeoRaster table, you must create the GeoRaster object and insert it into a GeoRaster table before you start working on it. To create a new GeoRaster object, you have the following options:
Initialize an empty GeoRaster object, using the SDO_GEOR.init function.
Create a blank GeoRaster object, using the SDO_GEOR.createBlank function.
You cannot perform any GeoRaster operations if the object has not been properly created (that is, if the object is an atomic null). The SDO_GEOR.init and SDO_GEOR.createBlank functions initialize GeoRaster objects with their raster data table and raster ID values if these are not already specified, and the GeoRaster DML trigger ensures that the raster data table name and raster ID value pair is unique for the current user.
If the new GeoRaster object will hold raster cell data (resulting from another GeoRaster procedure, such as SDO_GEOR.importFrom, SDO_GEOR.subset, or SDO_GEOR.copy), and if the raster data table for this new GeoRaster object does not exist, you must first create the raster data table. For information about creating a raster data table, including examples, see Creating Raster Data Tables.
To avoid potential GeoRaster data problems (some of which are described in Maintaining GeoRaster Objects and System Data in the Database), an initialized GeoRaster object must be registered in the GeoRaster system views, which is done automatically when you insert the GeoRaster object into a GeoRaster table. This should be done before you perform any other operations on the GeoRaster object. Any GeoRaster operations that need to manipulate the raster data table raise an exception if the source or target GeoRaster object is not registered.
3.5 Loading Raster Data
To load and export imagery or raster data, you can consider third-party ETL tools (see the note in GeoRaster Tools: Viewer_ Loader_ Exporter). For example, you can use the gdal_translate command line and other GDAL utilities, which fully support GeoRaster through the Oracle Spatial GeoRaster driver.
You can also use features in GeoRaster to load raster data, With GeoRaster, you have the following options:
Use the GDAL based ETL tool for concurrent batch loading and exporting. This tool is described in GDAL-Based ETL Wizard for Concurrent Batch Loading and Exporting.
In PL/SQL call the SDO_GEOR_GDAL.translate procedure to load images into GeoRaster objects.
In PL/SQL, call the SDO_GEOR.importFrom procedure to load images into GeoRaster objects.
Use the GeoRaster JAI-based loader tool or viewer tool, which are described in JAI-Based Viewer_ Loader_ and Exporter.
With the last two options (SDO_GEOR.importFrom and JAI-based tool), you can do the following:
Compress raster data and store the data in JPEG-compressed or DEFLATE-compressed GeoRaster objects.
Load an ESRI world file or a Digital Globe RPC text file (.rpb) into an existing GeoRaster object, and georeference the raster data without reloading it. You can also specify an SRID with the world file and generate the spatial extent of the data.
Load a GeoTIFF format file with georeferencing, with or without raster data. To load and export the georeferencing information of GeoTIFF images, the GeoTIFF libraries are required. See Georeferencing GeoRaster Objects for instructions.
Because an ESRI world file or .
rpb file does not contain coordinate system information, you can specify the SRID value of a coordinate reference system for the load operation. However, if you do not specify an SRID, the model SRID of the GeoRaster objects is set to 0 (zero) by the loader, which means that the GeoRaster object is invalid, and therefore you must use the SDO_GEOR.setModelSRID procedure to specify a valid model space for this object. If you do not yet know the coordinate system of the model space, you can specify the SRID value as 999999, which means that the coordinate reference system is unknown. (Specifically, SRID 999999 is associated with a coordinate reference system named
unknown CRS.) Later, when you know the actual coordinate reference system of the model space, you can set the SRID value accordingly.
For more information about the
unknown CRS (SRID 999999) coordinate reference system, see Oracle Spatial and Graph Developer's Guide.
3.5.1 Loading with Blocking and Optimal Padding
Unless you want to load JPEG or JPEG2000 images and store them without any change, when you load an image or raster file into GeoRaster object, always consider and apply appropriate blocking of the data, because file formats might have very different blocking schemes. In general, blocking sizes should be 512x512 or larger. There is no absolute rule for the blocking sizes, but the larger the raster, the larger the blocking sizes you might use. For regular rasters, 512x512 to 2048x2048 is appropriate. For very small images (less than 1024x1024x3), no blocking may be a good choice. Avoid blocking sizes that are either too small (such as 64x64 and 128x128) or too large, and avoid extreme blocking sizes such as 0.5 (one-half), 1, or 8 rows of pixels per block. Generally, the rectangular shape of blocks should be a square or close to a square. For different applications, you might tune the blocking to balance efficient storage with optimal performance.
You should also always apply optimal padding during loading. In other words, specify
blocking=OPTIMALPADDING in addition to specifying
blocksize. GeoRaster applies padding to the right column and bottom row of blocks to make them the same size as other blocks. If the block size is not optimal for a specific raster, the default resulting padding would waste some storage space. When you specify
blocking=OPTIMALPADDING, all GeoRaster procedures and the ETL tools automatically adjust the GeoRaster dimension size array so that it will be optimal for reducing the amount of padding in GeoRaster object storage. The adjustment is always made around the user-specified values. See the explanation of the
blocking keyword in the table in the Usage Notes for the SDO_GEOR_UTL.calcOptimizedBlockSizeprocedure.
For how to apply optimal padding when using the GDAL command line, see the following example:
gdal_translate -of georaster /images/image_1.tif \ georaster:georaster/georaster@my_db, image_table, raster \ -co "insert=(id,label,raster) values (1, 'image_1', sdo_geor.init('rdt_table', 1)" \ -co blockxsize= 512 \ -co blockysize=512 \ -co blockbsize=3 \ -co blocking=optimalpadding \ -co interleave=BIP
For how to apply optimal padding when using the SDO_GEOR.importFrom procedure, see the examples in the reference topic for that procedure.
3.5.2 Loading JPEG and JPEG 2000 Images Without Decompression
GeoRaster supports JPEG compression, in which the GeoRaster blocks are stored as JPEG files. GeoRaster also supports JPEG 2000 compression, in which the GeoRaster has a single block stored as a JPEG 2000 file. There are some special cases where you can load and export JPEG or JPEG 2000 images without decompressing and recompressing, thus improving performance significantly.
For JPEG, you can use the JAI-based GeoRaster loader to load the image directly without decompression and recompression if the image file is a JPEG file, the GeoRaster object's compression type is specified as JPEG-F and no blocking is specified for the GeoRaster object's storage (that is, the GeoRaster object has only one block).
For JPEG 2000, you can use GDAL or the GDAL-based GeoRaster ETL tool to load the image directly without decompression and recompression – if the image file is a JPEG2000 file and if no parameters in use require any change to the internal structure of the JPEG 2000 file. For example, the following script loads the JPEG 2000 file directly without decompression.
gdal_translate -of georaster /images/image_3.jp2 \ georaster:georaster/georaster@my_db,image_table,raster \ -co "insert=(id,label,raster) values (3, 'image_3', sdo_geor.init('rdt_table', 3)" \ -co compress=jp2-f
However, if any of the parameter in use require changing the internal structure of the JPEG 2000 data, direct loading will not be possible. The following example requires decompression and recompression, resulting in a substantial increase of the loading time.
gdal_translate -of georaster /images/image_4.jp2 \ georaster:georaster/georaster@my_db,image_table,raster \ -co "insert=(id,label,raster) values (4, 'image_4', sdo_geor.init('rdt_table', 4)" \ -co compress=jp2-f \ -co blockxsize=1024 \ -co blockysize=1024 \ -srcwin 100 200 1000 1000 \ -outsize 50% 50%
3.5.3 Reformatting the Source Raster Before Loading
The GeoRaster JAI-based loader does not support source raster files in BSQ interleaving, and it might raise an "insufficient memory" error if the files are too big, and it might have other restrictions. To avoid such problems, you can reformat and reblock the source files so that they can be properly loaded. However, it is recommended that you use the GDAL-based ETL loader, which generally does not have such issues and requirements.
As an example, one way to do this is to use GDAL, an Open Source raster transformation library available from
http://www.gdal.org, to reformat or reblock the image or raster file so that JAI (Java Advanced Imaging) can handle it. GDAL supports GeoRaster natively and can import and export GeoRaster objects directly, and can also process GeoRaster objects; for more information, see
http://www.oracle.com/technetwork/database/enterprise-edition/getting-started-with-gdal-133874.pdf. You can also use GDAL to generate TFW files. For example, execute commands such as the following two (each command on a single line) using the GDAL command line or (for batch conversion) shell:
gdal_translate -of GTiff -co "TFW=YES" -co "INTERLEAVE=PIXEL" -co "TILED=YES" D:\my_image.tif D:\my_new_image.tif gdal_translate -of GTiff -co "TILED=YES" -co "TFW=YES" D:\my_image.ecw D:\my_new_image.tif
In the preceding example, the first command generates a TFW file, changes the interleaving to BIP (which is supported by JAI), and reblocks the image to 256x256. The second command converts ECW to TIFF, generates TFW, and reblocks the image.
Then use the GeoRaster loader tool (described in GeoRaster Tools: Viewer_ Loader_ Exporter) , specifying reblocking so that the image can be loaded successfully and later retrieved from the database efficiently, as in the following example (a single command):
java -Xmx1024m oracle.spatial.georaster.tools.GeoRasterLoader mymachine db11 6521 georaster georaster thin 32 T globe image "blocking=true, blocksize=(512,512,3)" "D:my_image.tif,2,RDT_15, D:\my_image.tfw,82213"
If you receive an "insufficient memory" error when calling SDO_GEOR.importFrom to load a very large image, try loading the image with a different blocking size parameter or reblock the image into smaller internal tile sizes using GDAL before loading. For extremely large images, you can also use GDAL to tile the image into multiple smaller image files with sizes that JAI can handle, or you use GDAL to load and export the images directly.
3.6 Validating GeoRaster Objects
Before you use a GeoRaster object or after you manually edit the raster data and metadata of a GeoRaster object, you should ensure that the object is valid. Validation for a GeoRaster object includes checking the registration of the GeoRaster object, checking the metadata and the raster cell data, and making sure that the metadata and data are consistent. For example, validation checks the raster type, dimension information, and the actual sizes of cell blocks, and it performs other checks.
If you used the GeoRaster loader tool described in GeoRaster Tools: Viewer_ Loader_ Exporter, the GeoRaster objects were validated during the load operation.
GeoRaster provides the following validation subprograms:
SDO_GEOR.validateGeoRaster validates the GeoRaster object, including cell data and metadata. It returns
TRUEif the object is valid; otherwise, it returns one of the following: an Oracle error code indicating why the GeoRaster object is invalid,
FALSEif validation fails for an unknown reason, or
NULLif the GeoRaster object is null. You should always use this function after you create a GeoRaster object.
SDO_GEOR.schemaValidate validates the metadata against the GeoRaster XML schema. You can use this function to locate errors if the SDO_GEOR.validateGeoRaster function returned the error code 13454. The SDO_GEOR.schemaValidate and SDO_GEOR.validateGeoRaster functions do not validate the spatial extent geometry.
SDO_GEOR.validateBlockMBR validates the
blockMBRgeometry associated with each raster block stored in the raster data table. If there are any invalid
blockMBRgeometries, call the SDO_GEOR.generateBlockMBR procedure to regenerate them.
3.7 Georeferencing GeoRaster Objects
Georeferencing, as explained in Georeferencing, establishes the relationship between cell coordinates of GeoRaster data and real-world ground coordinates (or some local coordinates). If you need to georeference GeoRaster objects, the following approaches are available:
If the original image is already georeferenced and if the georeferencing information is stored in an ESRI world file or .
rpbfile containing RPC coefficients you can use the SDO_GEOR.importFrom procedure to load an ESRI world file or .
rpbfile from a file or from a CLOB object, along with the image data itself (in either FILE or BLOB format). You can also use the GeoRaster client-side loader tool (described in GeoRaster Tools: Viewer_ Loader_ Exporter) to load an ESRI world file or .
rpbfile from a file, along with the image file itself.
Because an ESRI world file or .
rpbfile does not specify the model coordinate system, you can set the model space of the georeferenced GeoRaster object using an Oracle SRID in either of the following ways: specify the SRID along with the world file as a parameter to the SDO_GEOR.importFrom procedure or the GeoRaster client-side loader (described in GeoRaster Tools: Viewer_ Loader_ Exporter); or, after loading the world file, call the SDO_GEOR.setModelSRID procedure. You can also call the SDO_GEOR.setModelSRID procedure to change the model space of a georeferenced GeoRaster object.
If the original image is a georeferenced GeoTIFF image, you can use the SDO_GEOR.importFrom procedure to load the image with georeferencing, by specifying
GEOTIFFas the input format. To load only the georeferencing information from a GeoTIFF image, without the raster image data, into an existing GeoRaster object, add the
raster=falsestorage parameter. You can specify a backup SRID with the
sridstorage parameter, in case the GeoTIFF configuration values do not match any SRID recognized by Oracle Spatial and Graph.
PixelIsArearaster space is equivalent to the GeoRaster upperleft-based cell coordinate system. An export to GeoTiff is always in
PixelIsArearaster space, with a half-pixel adjustment of the affine transformation if the GeoRaster object is in center-based cell coordinate system. An import from GeoTIFF is always to the GeoRaster center-based cell coordinate system, with a half-pixel adjustment of the affine transformation if the GeoTIFF file is specified in
You can also use the GeoRaster client-side loader tool (described in GeoRaster Tools: Viewer_ Loader_ Exporter) to load GeoTIFF images with georeferencing, using the storage parameter
geotiff=true. If you omit this parameter or specify
geotiff=false, the image is loaded as a simple TIFF image without georeferencing. The
sridstorage parameters also apply to the client-side loader tool.
To load or export GeoTIFF images with the GeoRaster client-side tools, add the following GeoTIFF libraries to your CLASSPATH definition:
xtiff-jai.jar(available from the SourceForge Extensible-TIFF-JAI group)
geotiff-jai.jar(available from the SourceForge GeoTIFF-JAI group)
To load or export GeoTIFF images with the SDO_GEOR.importFrom or SDO_GEOR.exportTo procedure, load these libraries into the MDSYS schema by connecting to the database as the SYSTEM user, editing
/md/admin/sdoldgtf.sqlas needed to reflect the paths to the
geotiff-jai.jarfiles, and running the
sdoldgtf.sqlSQL*Plus script. As an alternative to using the
sdoldgtf.sqlscript, you can enter the following commands:
loadjava -user system/password@database -resolve -force -synonym -schema MDSYS -grant PUBLIC xtiff-jai.jar loadjava -user system/password@database -resolve -force -synonym -schema MDSYS -grant PUBLIC geotiff-jai.jar
If the database is downgraded to a release before Oracle Database 11g, these libraries should be uninstalled according to the script in
/md/admin/sdormgtf.sql, editing it as needed to reflect the paths to the
geotiff-jai.jarfiles, and either running the
sdormgtf.sqlscript or entering the following commands:
dropjava -user system/password@database -resolve -force -synonym -schema MDSYS -grant PUBLIC xtiff-jai.jar dropjava -user system/password@database -resolve -force -synonym -schema MDSYS -grant PUBLIC geotiff-jai.jar
You can use the SDO_GEOR.setSRS procedure to add, modify, and delete georeferencing information by directly accessing the GeoRaster SRS metadata. For example, you can create an SDO_GEOR_SRS object and assign the coefficients and related georeferencing information, and then call the SDO_GEOR.setSRS procedure to add or update the spatial reference information of any GeoRaster object. You can use the SDO_GEOR.setSRS procedure to set up the spatial reference information for all supported functional fitting georeferencing models. Examples of setting up the SRS information from an existing DLT model and from an existing RPC model are included in reference section for the SDO_GEOR.setSRS procedure.
If you know that one GeoRaster object has the same SRS information as another GeoRaster object, you can call the SDO_GEOR.getSRS function to retrieve an SDO_GEOR_SRS object from this GeoRaster object, and then call the SDO_GEOR.setSRS procedure to georeference the first GeoRaster object.
If the GeoRaster object can be georeferenced using an affine transformation, you can call the SDO_GEOR.georeference procedure to georeference a GeoRaster object directly. As described in the reference information for the SDO_GEOR.georeference, this procedure takes the coefficients
Fand other information, converts them into the coefficients
f, and stores them in the spatial reference information of a GeoRaster object. If the original raster data is rectified and if the model coordinate of its origin (upper-left corner) is (x0, y0) and its spatial resolution or scale is
s, then the following are true: A = s, B = 0, C = x0, D = 0, E = -s, F = y0.
If you have ground control points (GCPs) or want to collect GCPs yourself, you can call the SDO_GEOR.georeference function to georeference the GeoRaster object. For more information, see Advanced Georeferencing.
Based on the SRS information of a georeferenced GeoRaster object, transforming GeoRaster coordinate information means finding the model (ground) coordinate associated with a specific cell (raster) coordinate, and the reverse. That is, you can do the following:
Given a specific cell coordinate, you can find the associated model space coordinate using the SDO_GEOR.getModelCoordinate function. For example, if you identify a point in an image, you can find the longitude and latitude coordinates associated with that point.
Given a model space coordinate, you can find the associated cell coordinate using the SDO_GEOR.getCellCoordinate function. For example, if you identify longitude and latitude coordinates, you can find the cell in an image associated with those coordinates.
3.8 Generating and Setting Spatial Extents
When a GeoRaster object is created, its spatial extent (
spatialExtent attribute, described in spatialExtent Attribute) is not necessarily the enclosing geometry in its model space coordinate system. The spatial extent (footprint) geometry might initially be null, or it might reflect the cell space coordinate system or some other coordinate system. The ability to generate and set spatial extents is useful for building large GeoRaster databases of a global or large regional scope, in which the spatial extents are in one global geodetic coordinate system while the GeoRaster objects (imagery, DEMs, and so on) are in different projected coordinate systems. In such a case, you can create a spatial (R-tree) index on the spatial extents, which requires that all spatial extent geometries have the same SRID value.
To ensure that the spatial extent geometry of each GeoRaster object in a table is correct for its model space coordinate system (or for any other coordinate system that you may want to use), you must set the spatial extent. Moreover, to use a spatial index on the spatial extent geometries (described in Indexing GeoRaster Objects), all indexed geometries must be based on the same coordinate system (that is, have the same SRID value).
You can set the spatial extent in any of the following ways: specify
spatialExtent=TRUE as a storage parameter to the SDO_GEOR.importFrom procedure or the GeoRaster client-side loader (described in GeoRaster Tools: Viewer_ Loader_ Exporter), use the SQL UPDATE statement, or set the spatial extent during loading with GDAL. If you use the SDO_GEOR.importFrom procedure or the loader, the SRID cannot be null or 0 (zero), and if there is an R-tree index on the GeoRaster spatial extent, the SRID of the spatial extent must match the SRID of the existing spatial index; otherwise, the spatial extent is set to a null value.
In addition, if you do not already have the spatial extent geometry, you can generate it using the SDO_GEOR.generateSpatialExtent function, and use that geometry to update the GeoRaster object. The following example updates the spatial extent geometry of a specified GeoRaster object in the CITY_IMAGES table (created in Example 3-1 in Creating a GeoRaster Table) to the generated spatial extent (reflecting the model coordinate system) of that object:
UPDATE city_images c SET c.image.spatialExtent = sdo_geor.generateSpatialExtent(image) WHERE c.image_id = 100; COMMIT;
The following example updates the spatial extent geometry of all GeoRaster objects in the CITY_IMAGES table to the generated spatial extent (reflecting the model coordinate system) of that object:
UPDATE city_images c SET c.image.spatialExtent = sdo_geor.generateSpatialExtent(image) WHERE c.image.spatialExtent is null; COMMIT;
If you already know the spatial extent geometry for a GeoRaster object, or if you want the spatial extent geometry to be based on a coordinate system other than the one for the model space, construct the SDO_GEOMETRY object or select it from a table, and then update the GeoRaster object to set its spatial extent attribute to that geometry, as shown in the following example:
DECLARE geom sdo_geometry; BEGIN -- Set geom to an SDO_GEOMETRY object that covers the spatial extent -- of the desired GeoRaster object. If necessary, perform coordinate -- system transformation before setting geom. -- geom := sdo_geometry(...); UPDATE city_images c SET c.image.spatialExtent = geom WHERE c.image_id = 100; COMMIT; END;
3.8.1 Special Considerations if the GeoRaster Table Has a Spatial Index
If you create a spatial R-tree index on the GeoRaster spatial extents (as described in Indexing GeoRaster Objects), all spatial extent geometries must have the same SRID value. However, the GeoRaster objects may have different model SRIDs, and most GeoRaster operations automatically generate a spatial extent for the output GeoRaster objects based on the model SRID of the source GeoRaster object or objects. This can cause problems when the resulting GeoRaster object with a spatial extent is updated into a GeoRaster table, which might already have a spatial index built on its
spatialExtent attribute but using a different SRID.
In such cases, you must transform the spatial extent to the same SRID as that of the spatial index before the insert or update operation. The following example performs a mosaic operation, but then transforms the spatial extent of the resulting GeoRaster object to SRID 4326 before updating the GeoRaster table with that object.
DECLARE gr sdo_georaster; BEGIN SELECT georaster INTO gr FROM mosaic_test WHERE georid=1 FOR UPDATE; sdo_geor.mosaic('mosaic_data', 'georaster', gr, 'blocking=OPTIMALPADDING, blocksize=(512,512)'); -- Transform the spatial extent geometry, if ncessary. -- In this example example, the modelSRID of the mosaic is 27302, -- but the SRID of the spatial index on mosaic_test is 4326. gr.spatialExtent := sdo_cs.transform(gr.spatialExtent, 4326); UPDATE mosaic_test SET georaster=gr WHERE georid=1; END; /
If a spatial R-tree index exists, a commit operation after an insert or update operation causes the index to be updated if the inserted or updated GeoRaster object has a spatial extent geometry. This could slow some operations if you perform a commit after each operation, particularly for batch jobs such as batch image loading. It is usually more efficient to balance the performance of index updates with GeoRaster operations, and to commit only in batches after the operations.
For example, image data loading (the SDO_GEOR.importFrom procedure and the GeoRaster loader) is followed by an internal commit operation, so it would be inefficient to load while generating spatial extents by specifying
spatialExtent=TRUE. Instead, you should probably specify
spatialExtent=FALSE, and then update the
spatialExtent attribute afterward, to speed the loading process.
3.9 Indexing GeoRaster Objects
GeoRaster data can be indexed in various ways. The most important index you can create on a GeoRaster object is a spatial (R-tree) index on the spatial extent (footprint) geometry of the GeoRaster object (
spatialExtent attribute, described in spatialExtent Attribute). For large-scale geospatial image and raster databases, you should always create spatial indexes on the GeoRaster columns. The following are the basic steps to create a spatial index on GeoRaster column. (The examples assume that the GeoRaster table name is CITY_IMAGES and its GeoRaster column name is IMAGE.)
- Insert a row into the USER_SDO_GEOM_METADATA view with the georaster table name (CITY_IMAGES in this example) and the spatial extent of the GeoRaster column name (IMAGE.SPATIALEXTENT). Be sure that the correct SRID value (3371 in this example) is registered.
INSERT INTO user_sdo_geom_metadata (TABLE_NAME, COLUMN_NAME, DIMINFO, SRID) VALUES ( 'city_images', 'image.spatialextent', SDO_DIM_ARRAY( SDO_DIM_ELEMENT('X', -1000000000, 1000000000, 0.005), SDO_DIM_ELEMENT('Y', -1000000000, 1000000000, 0.005)), 3371 );
- Create a spatial index on the GeoRaster column, as in the following example which creates a spatial index named CITY_IMAGES_IDX on the spatial extents of the images using default values for all parameters.
CREATE INDEX city_images_idx ON city_images (image.spatialextent) INDEXTYPE IS MDSYS.SPATIAL_INDEX;
The preceding statement may fail if there are some invalid spatial extents or if the SRID values in the GeoRaster table do not match the SRID registered in the preceding step. If the statement fails, ensure that all GeoRaster objects have a valid
spatialExtentgeometry attribute and that all
spatialExtentgeometries have the same SRID. (Null for the
spatialExtentvalues is acceptable.) Then re-create the spatial index.
See also Special Considerations if the GeoRaster Table Has a Spatial Index for special considerations if the GeoRaster table already has a spatial index. For more information about creating spatial indexes and about advanced capabilities, see Oracle Spatial and Graph Developer's Guide.
You can also create one or more other indexes, such as:
Function-based indexes on metadata objects using the Oracle XMLType or Oracle Text document indexing functionality
Standard indexes on other user-defined columns of the GeoRaster table, such as cloud coverage, water coverage, or vegetation
You should also create a single B-tree index on the
columnBlockNumber columns of each raster data table. This should be done using
PRIMARY KEY (rasterID, pyramidLevel, bandBlockNumber,rowBlockNumber, columnBlockNumber), as shown in Example 3-2 and Example 3-3.
3.10 Viewing GeoRaster Objects
To view GeoRaster objects, you have the following options:
Call the SDO_GEOR.exportTo procedure to export GeoRaster objects to image files, and then display the images using image tools or a Web browser.
Use the standalone GeoRaster viewer tool (one of the tools described in GeoRaster Tools: Viewer_ Loader_ Exporter).
Use Oracle Fusion Middleware MapViewer or its associated Map Builder utility.
With the GeoRaster viewer tool, you can select a GeoRaster object of a database schema (user), query and display the whole or a subset of a GeoRaster object, zoom in and zoom out, scroll, and perform other basic operations. The pyramid level, cell coordinates, and model coordinates (if the object is georeferenced) are displayed for the point at the mouse pointer location. You can display individual cell values and choose different layers of a multiband or hyperspectral image for RGB full color display. The blocking boundaries can be overlapped on the top of the display. Depending on the data and your requests, the viewer can display the raster data in grayscale, pseudocolor, and 24-bit true color over an intranet or the Internet. Some of the basic GeoRaster metadata is also displayed.
The GeoRaster viewer tool allows you to display a virtual mosaic defined as one or a list of GeoRaster tables or views.
The GeoRaster viewer tool provides a set of image processing operators for enhanced display of the GeoRaster objects, especially for those whose cell depth is greater than 8 or is a floating-point number. It can also display and apply bitmap masks on the GeoRaster objects if they have bitmap masks.
The GeoRaster viewer tool also includes menu commands to call the GeoRaster loader and exporter tools, thus enabling you to use a single tool as an interface to the capabilities of all the GeoRaster tools.
Visualization applications can leverage the default RGBA and default pyramid level specifications in the GeoRaster objects. You can set up different bands in a multiband image as the default Red, Green, Blue, and Alpha channels by calling SDO_GEOR.setDefaultColorLayer or SDO_GEOR.setDefaultRed, SDO_GEOR.setDefaultGreen, SDO_GEOR.setDefaultBlue, and SDO_GEOR.setDefaultAlpha. For large images, you can call SDO_GEOR.setDefaultPyramidLevel to set up the best resolution (pyramid) level of an image for initial display in the applications. For example, for a complete overview of a whole image, it is best to set the top pyramid level as the default pyramid level.
3.11 Exporting GeoRaster Objects
To load and export imagery or raster data, always consider third-party ETL tools (see the note in GeoRaster Tools: Viewer_ Loader_ Exporter)
If you use features in GeoRaster to export GeoRaster objects to image files, you have the following options:
Use the GDAL-based ETL tool for concurrent batch exporting, which is described in GDAL-Based ETL Wizard for Concurrent Batch Loading and Exporting.
Call the SDO_GEOR.exportTo procedure (which can export either to a file or to a BLOB object).
Use the GeoRaster exporter tool or viewer tool, which are described in GeoRaster Tools: Viewer_ Loader_ Exporter.
3.12 Using GeoRaster with Workspace Manager and Label Security
Oracle Workspace Manager provides a versioning capability for the raster blocks of a GeoRaster object. Oracle Label Security supports GeoRaster objects with enhanced security at the row level of raster blocks.
To use GeoRaster with Oracle Workspace Manager or Oracle Label Security, you should create a raster data table (RDT) as a relational table for the GeoRaster objects (see Example 3-3). You do not need to define an object view of SDO_RASTER type on the base relational RDT.
3.12.1 Using GeoRaster with Workspace Manager
With Workspace Manager, you can conveniently manage changes to the raster data by saving different raster data versions and making modifications in different workspaces. To use GeoRaster with Workspace Manager, you must use relational raster data tables for raster storage and version-enable these relational raster data tables. For example (general format):
EXECUTE DBMS_WM.EnableVersioning (<rdt_relational_table>, 'VIEW_WO_OVERWRITE');
You can version-enable only raster data tables. Do not version-enable any GeoRaster tables, where GeoRaster objects are stored, and do not perform any operations that will require a GeoRaster table to be modified while you are in a workspace.
After you version-enable a relational RDT, you can use the subprograms in the DBMS_WM package to manage changes to the raster data. If you need to directly modify a raster block, call the DBMS_WM.copyForUpdate procedure before the operation, as shown in the following example:
declare geor sdo_georaster; cond varchar2(1000); lb blob; r1 raw(1024); amt number; begin r1 := utl_raw.copies(utl_raw.cast_to_raw('0'),1024); select georaster into geor from georaster_table where georid=1; cond := 'rasterId=' || geor.rasterId || ' AND pyramidLevel=0 AND ' || ' bandBlockNumber=0 AND rowBlockNumber=0 AND columnBlockNumber=0'; dbms_wm.copyForUpdate(geor.rasterDataTable, cond); sdo_geor.getRasterBlockLocator(geor, 0, 0, 0, 0, lb, null, 'TRUE'); amt := 1024; dbms_lob.write(lb, amt, 1, r1); end; /
However, if you modify raster data using GeoRaster subprograms, you do not need to call the DBMS_WM.copyForUpdate procedure beforehand.
For information about Workspace Manager, see Oracle Database Workspace Manager Developer's Guide.
3.12.2 Using GeoRaster with Label Security
Oracle Label Security provides row-level access control for sensitive data based on a user's level of security clearance. To use GeoRaster with Label Security, follow these basic steps:
- Create the GeoRaster table and relational RDT or RDTs.
- Create an Oracle Label Security policy and define the label components.
- Create labeling functions for the GeoRaster table and the relational RDT or RDTs.
The labels for rows in a GeoRaster table should be generated according to the application's requirements. Use the same label for both the row that stores a GeoRaster object and for the GeoRaster object's raster rows in the associated RDT; otherwise, the GeoRaster objects might be invalid or have an inconsistent status.
The following example creates the labeling function for a relational RDT:
CREATE OR REPLACE FUNCTION gen_rdt_label(rdt_name varchar2, rid number) RETURN LBACSYS.LBAC_LABEL AS tabname varchar2(80); schema varchar2(32); grcol varchar2(1024); colname varchar2(30); label NUMBER; BEGIN EXECUTE IMMEDIATE 'SELECT v.owner, v.table_name, v.column_name grcol, p.column_name ' || ' FROM all_sdo_geor_sysdata v, all_sa_policies p, all_sa_table_policies t ' || ' WHERE v.rdt_table_name=:1 AND v.raster_id=:2 AND ' || ' v.owner=t.schema_name AND v.table_name=t.table_name AND ' || ' p.policy_name=t.policy_name ' INTO schema, tabname, grcol, colname USING upper(rdt_name), rid; EXECUTE IMMEDIATE 'SELECT t.' || colname || ' FROM ' || schema || '.' || tabname || ' t ' || ' WHERE t.' || grcol || '.rasterdatatable=:1 AND ' || ' t.' || grcol || '.rasterid=:2' INTO label USING upper(rdt_name), rid; RETURN LBACSYS.LBAC_LABEL.NEW_LBAC_LABEL(label); END; /
- Apply the Label Security policy to a GeoRaster table and its associated RDT or RDTs.
The following example (general format) applies a Label Security policy to an RDT using the labeling function example from the preceding step.
BEGIN SA_POLICY_ADMIN.REMOVE_TABLE_POLICY(<policy_name>,<schema_name>,<rdt_relational_table>); SA_POLICY_ADMIN.APPLY_TABLE_POLICY( POLICY_NAME => <policy_name>, SCHEMA_NAME => <schema_name>, TABLE_NAME => <rdt_relational_table>, TABLE_OPTIONS => 'READ_CONTROL,WRITE_CONTROL,CHECK_CONTROL', LABEL_FUNCTION => '<schema_name>.gen_rdt_label(<rdt_relational_table>,:new.rasterid)', PREDICATE => NULL); END; /
- Create and authorize users, and complete other administrative tasks related to Label Security.
You can load GeoRaster data before or after applying the policy to the tables.
The ALL_SDO_GEOR_SYSDATA view (described in GeoRaster System Data Views (xxx_SDO_GEOR_SYSDATA)) contains system data for all GeoRaster objects accessible by the current user, and accessibility in this case is determined by the user's privileges as defined in the context of discretionary access control (DAC).
After the label for a GeoRaster table row is updated, ensure that the related data labels in the RDT are updated, so that the labels are synchronized.
For information about Label Security, see Oracle Label Security Administrator's Guide.
3.13 Maintaining Efficient Tablespace Use by GeoRaster Objects
After delete or rollback operations, unused space allocated to a raster data table might not be promptly returned to the underlying tablespace. This could result in wasted tablespace area, and it can be a significant issue if the amount of raster data is large. If the raster data table is created using BasicFiles LOBs in an automatic segment space management tablespace, you can explicitly shrink the
rasterBlock LOB segment or the raster data table by altering the raster data table, as shown in Example 3-4 and Example 3-5.
Example 3-4 Shrinking a BasicFile RasterBlock LOB Segment
ALTER TABLE city_images_rdt MODIFY LOB (rasterBlock) (SHRINK SPACE);
Example 3-5 Shrinking a Raster Data Table
ALTER TABLE city_images_rdt ENABLE ROW MOVEMENT; ALTER TABLE city_images_rdt SHRINK SPACE CASCADE;
If you are using SecureFiles, or if you are using BasicFiles allocated in a manual segment space management tablespace, you cannot reclaim unused space using the ALTER TABLE statements as shown in the preceding examples. Instead, you should create some working (for temporary use) raster data tables and try to put any intermittent results in these RDTs, and then drop these working RDTs after they are no longer needed.
3.14 Checking GeoRaster Tables and Objects in the Database
For database management purposes, you might need check on GeoRaster tables and objects in the whole database or under a specific schema. After the GeoRaster database is created, you have the following options for checking or listing existing GeoRaster tables, RDT tables, and GeoRaster objects.
Use the following subprograms check the status of existing GeoRaster objects and related objects in the current schema or the database, depending on the privileges associated with the database connection.
SDO_GEOR_ADMIN.listGeoRasterObjects lists all GeoRaster objects defined in the current schema; or if you call this function while connected as the MDSYS user, all GeoRaster objects defined in the database are listed.
SDO_GEOR_ADMIN.listGeoRasterColumns lists all GeoRaster columns defined in the current schema; or if you call this function while connected as the MDSYS user, all GeoRaster columns defined in the database are listed.
SDO_GEOR_ADMIN.listGeoRasterTables lists all GeoRaster tables defined in the current schema; or if you call this function while connected as the MDSYS user, all GeoRaster tables defined in the database are listed.
SDO_GEOR_ADMIN.listRDT lists all raster data tables (RDTs) defined in the current schema; or if you call this function while connected as the MDSYS user, all raster data tables (RDTs) defined in the database are listed.
SDO_GEOR_ADMIN.listRegisteredRDT lists all registered raster data tables (RDTs) defined in the current schema; or if you call this function while connected as the MDSYS user, all registered RDTs defined in the database are listed . An RDT is registered if at least one entry in the SYSDATA table refers to it.
SDO_GEOR_ADMIN.listUnregisteredRDT lists all unregistered raster data tables (RDTs) defined in the current schema; or if you call this function while connected as the MDSYS user, all unregistered RDTs defined in the database are listed.. An RDT is unregistered if no entry in the SYSDATA table refers to it.
Run SQL queries directly against GeoRaster sysdata views, and check or list GeoRaster tables and objects stored in the different schemas. This approach is more flexible than calling subprograms. It also enables some query results that cannot be returned by functions defined in the SDO_GEOR_ADMIN package. The following are some sample queries.
List all GeoRaster objects that are defined in the schema HERMAN and MYTEST and accessible by the current schema.
SELECT owner,TABLE_NAME,COLUMN_NAME,RDT_TABLE_NAME,RASTER_ID from all_sdo_geor_sysdata where owner='HERMAN' or owner='MYTEST';
Count the total number of GeoRaster objects accessible by the current schema.
SELECT count(*) from all_sdo_geor_sysdata;
Count the total number of GeoRaster objects stored in the GeoRaster table GTF_TABLE in the current schema.
SELECT count(*) from user_sdo_geor_sysdata where TABLE_NAME='GTF_TABLE';
List all GeoRaster objects stored in the RDT table RDT_1 in the current schema.
SELECT TABLE_NAME,COLUMN_NAME,RDT_TABLE_NAME,RASTER_ID from user_sdo_geor_sysdata where RDT_TABLE_NAME='RDT_1';
Find out all GeoRaster tables that store some raster data in or reference the RDT table RDT_1 in the current schema.
SELECT distinct TABLE_NAME from user_sdo_geor_sysdata where RDT_TABLE_NAME='RDT_1';
List all RDT tables that are used by the GeoRaster table GTF_TABLE in the current schema.
SELECT distinct RDT_TABLE_NAME from user_sdo_geor_sysdata where TABLE_NAME='GTF_TABLE';
3.15 Maintaining GeoRaster Objects and System Data in the Database
Although GeoRaster provides internal database mechanism to prevent the creation of invalid GeoRaster objects and system data, sometimes such GeoRaster objects and system data might exist in the database, especially after an upgrade from a previous release, or after some user errors in operations on GeoRaster system data. Examples of such invalid objects and system data include the following:
An entry in the GeoRaster system data views (xxx_SDO_GEOR_SYSDATA, described in GeoRaster System Data Views (xxx_SDO_GEOR_SYSDATA)) refers to a nonexistent GeoRaster table or column.
Two or more GeoRaster objects have the same pair of RDT name and raster ID values.
Some GeoRaster objects, tables, columns, or RDTs not registered.
An RDT name is not unique.
A GeoRaster object is non-empty or nonblank, but an associated RDT does not exist.
After a database upgrade, you should do the following.
Call the SDO_GEOR_ADMIN.isGeoRasterEnabled function to ensure that GeoRaster is enabled for the current schema.
Call the SDO_GEOR_ADMIN.isUpgradeNeeded function to check for any invalid GeoRaster objects and invalid system data for the current version.
If there are any errors or invalid data, call the SDO_GEOR_ADMIN.upgradeGeoRaster function to have the problems automatically corrected.
If you connect as user MDSYS, the SDO_GEOR_ADMIN.upgradeGeoRaster function upgrades all GeoRaster objects in the database; otherwise, it upgrades only GeoRaster objects in the schema of the current user. (See the reference and usage information about SDO_GEOR_ADMIN.upgradeGeoRaster.
For regular maintenance due to possible user errors, several functions and procedures will be helpful in checking for and correcting invalid GeoRaster objects and system data entries:
To check if GeoRaster is enabled, call SDO_GEOR_ADMIN.isGeoRasterEnabled
To enable GeoRaster. call SDO_GEOR_ADMIN.enableGeoRaster
To check for dangling raster data, call SDO_GEOR_ADMIN.listDanglingRasterData.
To correct all invalid system data entries, call SDO_GEOR_ADMIN.maintainSysdataEntries.
To create correct DML triggers for all GeoRaster columns, call SDO_GEOR_ADMIN.registerGeoRasterColumns.
To register all existing GeoRaster objects in the sysdata table, call SDO_GEOR_ADMIN.registerGeoRasterObjects.
See the reference and usage information about these procedures and functions in SDO_GEOR_ADMIN Package Reference.
3.16 Transferring GeoRaster Data Between Databases
You can use either the Data Pump Export and Import utilities or the original Export and Import utilities to transfer GeoRaster data between databases. You must export and import rows from both the GeoRaster table and its related raster data table or tables. After the transfer, you do not need to insert the GeoRaster system data for the imported GeoRaster objects into the USER_SDO_GEOR_SYSDATA view (described in GeoRaster System Data Views (xxx_SDO_GEOR_SYSDATA)) in the target schema; however, you should use the SDO_GEOR.validateGeoRaster function to check the validity of imported GeoRaster objects before you perform any operations on these objects.
For information about the Data Pump Export and Import utilities and the original Export and Import utilities, see Oracle Database Utilities.
To transfer GeoRaster data between databases, follow these general steps:
3.16.1 Checking for and Resolving Conflicts
For a successful import of GeoRaster data into a target database, there must be no conflicts in the target schema's GeoRaster system data. The following conditions can cause a conflict:
A raster data table with the same name is already defined in another schema in the target database.
For example, you might plan to import a GeoRaster object by creating its raster data table (RDT) in the target schema, but an existing RDT in the target schema might already have the same name. In this case, you should use the SDO_GEOR_ADMIN.listRDT or SDO_GEOR_ADMIN.isRDTNameUnique function to check both source database and target database to see if there are RDT name conflicts; and if there are any conflicts, use the SDO_GEOR_UTL.renameRDT procedure to rename the RDT to a different name in the target database to solve the conflicts before you import the GeoRaster objects.
Any pairs of raster data table name and raster ID to be inserted into the target schema's USER_SDO_GEOR_SYSDATA view are not unique.
For example, if you import RDT data by appending to an existing RDT in the target database, this conflict might occur. In this case, before importing the data into the target database, use the SDO_GEOR_ADMIN.listGeoRasterObjects function to list all GeoRaster objects defined in the target schema, and make sure that there are no conflicts in the combination of RDT name and raster ID between existing GeoRaster data and the GeoRaster data to be imported. If there are any conflicts, change the raster ID of the GeoRaster object in the target schema to resolve the conflicts; otherwise, those GeoRaster objects with conflicts in the dump file will get rejected when you perform import process.
If you need to check the raster data table (RDT) name and raster ID (RID) information in the dump file, you have the following options: check the information in the source database; request the information from the provider of the dump file; load the dump file into a separate test database and check the information there; or (if you cannot use a separate database for testing) load the dump file into a test schema in the current database and check the information. To load the dump file into a test schema in the current database and check the information, follow these steps:
Create a test schema in the target database.
Load all GeoRaster tables into this test schema from the dump file, using the Data Pump Import utility with the
CONTENT = METADATA_ONLYparameter.
Connect to the database as the MDSYS user, and disable all DML triggers on the GeoRaster tables that were loaded in the preceding step.
Load the data into the GeoRaster tables, using the Data Pump Import utility with the
CONTENT = DATA_ONLYparameter.
Retrieve the RDT/RID (raster data table name and raster ID) pairs directly from the GeoRaster tables in the test schema.
After you resolve conflicts, you should ensure the integrity of GeoRaster metadata and data (see Maintaining GeoRaster Objects and System Data in the Database). You should also validate any fixed GeoRaster objects before performing a commit or any other operation.
For general information about resolving conflicts during import operations, see the description of the
TABLE_EXISTS_ACTION parameter in the Data Pump Import chapter of Oracle Database Utilities.
3.16.2 Performing the GeoRaster Data Transfer
Performing the GeoRaster data transfer involves exporting data from one database and importing it into another.
To successfully import GeoRaster data into a Release 19c database, GeoRaster must be enabled for the imported schema and the schema user must have the CREATE TRIGGER privilege.
When you export GeoRaster data from one database and import it into another, the GeoRaster database management system ensures that the necessary GeoRaster internal DML triggers and system data entries are automatically generated after the GeoRaster tables and objects are imported into the target database. (GeoRaster internal DDL triggers are created when GeoRaster is enabled.)
Therefore, all GeoRaster internal DML triggers and DDL triggers (which maintain the integrity of the GeoRaster data) should be excluded in
impdp operations; otherwise, some
impdp errors such as the following will be raised, even though the errors can be safely ignored:
ORA-39083: Object type TRIGGER failed to create with error: ORA-13391: GeoRaster reserved names cannot be used to create regular triggers
To export GeoRaster data, do as you would for other types of data, but exclude the GeoRaster internal DML triggers (whose names start with
GRDMLTR_) and the internal DDL triggers (named
SDO_GEOR_BDDL_TRIGGER). For example:
expdp scott schemas=scott directory=dump_dir dumpfile=exp.dmp parfile=exclude.par Enter password: password
exclude.par file contains the following:
exclude=trigger:"like 'GRDMLTR_%'" exclude=trigger:"= 'SDO_GEOR_ADDL_TRIGGER'" exclude=trigger:"= 'SDO_GEOR_BDDL_TRIGGER'"
To import GeoRaster data, do as you would for other types of data, but exclude the GeoRaster internal DML triggers (whose names start with
GRDMLTR_) and DDL triggers (
SDO_GEOR_BDDL_TRIGGER from a Release 19c database) if you did not exclude them in the export operation. For example:
Ensure that no conflicts exist between the GeoRaster data to be imported and the existing GeoRaster data in the target database, as explained in Checking for and Resolving Conflicts.
If any conflicts are not resolved, some exceptions will be raised and only non-conflicted GeoRaster data will be imported into the target database.
Import GeoRaster data as you would for other types of data, but exclude the GeoRaster internal DML triggers (whose names start with
GRDMLTR_) and DDL triggers (
SDO_GEOR_BDDL_TRIGGERfrom a Release 19c database) if you did not exclude them in the export operation. For example:
impdp scott schemas=scott directory=dump_dir dumpfile=exp.dmp parfile=exclude.par Enter password: password
exclude.parfile contains the following:
exclude=trigger:"like 'GRDMLTR_%'" exclude=trigger:"= 'SDO_GEOR_ADDL_TRIGGER'" exclude=trigger:"= 'SDO_GEOR_BDDL_TRIGGER'"
3.17 Using Transportable Tablespaces with GeoRaster Data
You can use the Oracle Database transportable tablespaces feature with GeoRaster data.
If a tablespace to be transported contains any spatial indexes on the GeoRaster tables or raster data tables (RDTs), you may have to take some preparatory steps. See the Usage Notes for the SDO_UTIL.PREPARE_FOR_TTS and SDO_UTIL.INITIALIZE_INDEXES_FOR_TTS procedures in Oracle Spatial and Graph Developer's Guide for more information about using the transportable tablespace feature with spatial data.
For a successful import of GeoRaster data into a target database, there must be no conflicts in the target schema's GeoRaster system data. Before you transport the tablespace to another database or schema, it is recommended (but not required) that you check for and resolve such conflicts by following the procedure described in Checking for and Resolving Conflicts. For this reason, you should design GeoRaster tables and RDT tables so as to avoid such foreseeable conflicts before you use such transportable tablespaces in the source database.
Regardless or whether a transported tablespace has any spatial indexes, after transporting the tablespace that contains GeoRaster objects, do the following:
- Call the SDO_GEOR_ADMIN.registerGeoRasterObjects procedure (described in SDO_GEOR_ADMIN Package Reference) to register all GeoRaster objects in the current schema or new database.
- Before you use the transported GeoRaster data, perform the "regular maintenance" operations described in Maintaining GeoRaster Objects and System Data in the Database, to maintain GeoRaster objects and system data and to ensure all GeoRaster objects are correctly transported and properly registered.
- If you find any conflicts, call the SDO_GEOR_UTL.renameRDT or SDO_GEOR_UTL.makeRDTNamesUnique procedure to solve such conflicts, and validate again.
For detailed information about transportable tablespaces and transporting tablespaces to other databases, see Oracle Database Administrator's Guide.