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Current Oracle Spatial Blog Articles

    Convert Single Geometry to Multi-part Geometry in Oracle Spatial
    Optimized Rectangle to 5 Point Polygon
    Centroid Package now supports Y ordinate seeding
    Convert GeoJSON document to Sdo_Geometry objects
    Implementation Of Travelling Salesman Problem
    Create Polygon From Bearings And Distances
    Function That Returns a Compass Point From a Whole Circle Bearing
    Playing around with Centroids by using different seed values
    GeoRaptor 4.x Update 2
    Simple Oracle C Sprintf or Java String.format
    Some Oriented Point Functions
    Extracting Inner Rings Changed Ordinate Ordering: A Trap For Players Who Don't Read Documentation!
    PLS-00306: wrong number or types of arguments in call to 'SDO_GEOMETRY'
    Converting Google Earth Formatted Longitude/Latitude points to decimal degrees
    Oracle Business Intelligence Warehousing and Analytics - Spatial Summit
    How far inside, is inside? Measuring actual distance.
    Noding and building a polygon from single, overlapping linestrings
    Analyzing Spatial Query Performance Improvements in Oracle Spatial and Graph 12c Through Cross-Vendor Comparison
    ST_VertexN / ST_PointN - Extracting a specific point from any geometry
    Convert Single Point stored in SDO_ORDINATES to SDO_POINT_TYPE
    Aggregate APPEND Islands and XOR polygons
    Circular Arcs in Geodetic Polygons
    Some SDO_GEOMETRY/DIMINFO handling functions
    Applying And Extending Oracle Spatial - Book Released
    Changing all DIMINFO sdo_tolerance values for all metadata records in one go.
    Building Polygons from Incomplete Linestrings using ST_PolygonBuilder
    Computing Cardinal Directions to nearby geometries
    Intersecting two aggregated polygon layers with SC4O
    Spatial and Oracle 12c
    Update Triggers and SDO_GEOMETRY Equality
    Duplicate Geometry data and Data Models
    CENTROID package update
    How to calculate cumulative length of a linestring
    Useful Package of Wrapper Functions for Sdo_Util.AffineTransforms
    Compute Location from known Lat/Long point using delta easting and northing in miles
    SDO_AGGR_SET_UNION
    Sorting SDO_GEOMETRY data using the ORDER BY clause of a SELECT statement
    Creating linestrings from points
    Rounding Coordinates or Ordinates in SDO_GEOMETRY
    Effects of Sdo_Geometry Ordinate Precision on Performance
    Effects of Sdo_Geometry Ordinate Precision on Storage
    The Spatial filtering of geometries: The effect of tolerances on relationships
    Application of Delaunay Triangulation and Inverse Distance Weighting (IDW) in Oracle for Soils Interpolation
    Selecting all SDO_GTYPE values for all tables/sdo_geometry columns in a schema
    CENTROID package - Tips for Use
    Announcing the Spatial Companion For Oracle (SC4O)
    Filtering Rings (Oracle Spatial)
    Splitting a polygon using one or more linestrings
    isValid, isSimple, Dimension and CoordDim methods for SDO_Geometry
    Line Merging or Collecting lines together: ST_LineMerger
    ST_DeleteVertex for Oracle SDO_Geometry based on Jaspa/JTS
    3D/4D and SRID aware Conversion functions for SDO_Geometry: WKT and EWKT
    Topological vs Non-Topological Simplification/Generalization of Aggregated Area Geometies in Oracle
    Filtering very short linestrings via bitmap function index
    CENTROID For Oracle
    Gridding a sdo_geometry line/polygon object (Oracle)
    Finding centre and radius of a circular geometry
    Constraining geometry type for sdo_geometry column in a table.
    CASE Statements and SDO_GEOMETRY
    The Power of Constraints and Indexes for Spatial Constraints: stopping duplicate points
    Replacement for SDO_GEOM.RELATE - ST_Relate based on JTS
    Changing Oracle Spatial Index Parameters on existing index
    Writing Excel Spreadsheets files from within the Oracle database using Java and PL/SQL
    Writing xSV (eg csv) files from within the Oracle database using Java and PL/SQL
    A simple spike finder for Spatial/Locator
    JTS Java class compilation for 11g and above
    Random Spatial Search Procedure
    Geometry Snapping using JTS in Oracle
    Exposing JTS's MinimumBoundingCircle functionality
    Exposing JTS's Densifier functionality
    Using JTS's Comparison Functions - HausdorffSimilarityMeasure & AreaSimilarityMeasure with SDO_GEOMETRY
    Free JTS-based Area/Length Functions
    Handy way of systematically fixing polygon geometries with 13349 and other errors
    Standalone CENTROID package now available for download
    Free Union, Intersection, Xor and Difference Functions for Oracle Locator - Part 4 Processing Geodetic data
    Configurable Buffer: JTS and Oracle
    Free Union, Intersection, Xor and Difference Functions for Oracle Locator - Part 3
    Free Union, Intersection, Xor and Difference Functions for Oracle Locator - Part 2
    Free Union, Intersection, Xor and Difference Functions for Oracle Locator - Part 1
    Building Lines into Polygons in Oracle Locator / Spatial
    Finding Intersection Points between Line and Polygon
    SDO2GeoJSON
    Free version of sdo_length
    Alternative to my SQL based GetNumRings function
    External Tables and SDO_Geometry data.
    layer_gtype keyword issue when indexing linear data on 11g
    String Tokenizer for Oracle
    Free Aggregate Method for Concatenating 2D Lines in Oracle Locator 10g
    Reducing 5 Vertex Polygon to Optimized Rectangle
    Square Buffer
    Converting decimal seconds to string
    SDO_GEOM.VALIDATE_GEOMETRY_WITH_CONTEXT - 13356 Issues
    Valid conversion unit values for Oracle sdo_geom.sdo_length()
    Removing Steps in Gridded Vector Data - SmoothGrid for Oracle
    Oracle Spatial DISJOINT search/filtering
    Creating SDO_Geometry from geometric data recorded in the columns of a table
    Concave Hull Geometries in Oracle 11gR2
    Projecting SDO_GEOM_METADATA DIMINFO XY ordinates
    Instantiating MDSYS.VERTEX_TYPE
    New PL/SQL Packages - Rotate oriented point
    GeoRaptor Development Team
    Fast Refreshing Materialized View Containing SDO_GEOMETRY and SDO_GEOM.SDO_AREA function
    Performance of PL/SQL Functions using SQL vs Pure Code
    Implementing the BEST VicGrid Projection in Oracle 10gR2
    Making Sdo Geometry Metadata Update Generic Code
    ORA-13011 errors when using SDO_GEOM.VALIDATE_LAYER_WITH_CONTEXT()
    Extract Polygons from Compound Polygon
    Detecting sdo_geometries with compound (3-point Arcs) segments
    GEOMETRY_COLUMNS for Oracle Spatial
    Convert GML to SDO_Geometry in Oracle 10gR2
    Spatial Sorting of Data via Morton Key
    Swapping Ordinates in an SDO_GEOMETRY object
    New To_3D Function
    Extend (Reduce/Contract/Skrink) Function for Oracle
    Loading and Processing GPX 1.1 files using Oracle XMLDB
    Loading Spatial Data from an external CSV file in Oracle
    Calling the Oracle Spatial shapefile loader from within the Oracle database itself
    Implementing SDO_VertexUpdate/ST_VertexUpdate for Oracle
    Implementing SDO_RemovePoint/ST_RemovePoint for Oracle
    Implementing SDO_AddPoint/ST_AddPoint for Oracle
    ESRI ArcSDE Exverted and Inverted Polygons and Oracle Spatial
    Funky Fix Ordinates By Formula
    Implementing a SetPoint/ST_SetPoint function in Oracle
    Implementing an ST_SnapToGrid (PostGIS) function for Oracle Spatial
    Generating random point data
    Implementing an Affine/ST_Affine function for Oracle Spatial
    Implementing a Scale/ST_Scale function for Oracle Spatial
    Implementing a Parallel/ST_Parallel function for linestring data for Oracle Spatial
    Implementing a Rotate/ST_Rotate function for Oracle Spatial
    Limiting table list returned when connecting to Oracle Database using ODBC
    ST_Azimuth for Oracle: AKA Cogo.Bearing
    Implementing a Translate/ST_Translate/Move function for Oracle Spatial
    Elem_Info_Array Processing: An alternative to SDO_UTIL.GetNumRings and querying SDO_ELEM_INFO itself
    Minumum Bounding Rectangle (MBR) Object Type for Oracle
    How to extract elements from the result of an sdo_intersection of two polygons.
    How to restart a database after failed parameter change
    Fixing failed spatial indexes after import using data pump
    generate_series: an Oracle implementation in light of SQL Design Patterns
    Multi-Centroid Shootout
    Oracle Spatial Centroid Shootout
    On the use of ROLLUP in Oracle SELECT statements
    Surrounding Parcels
    Spatial Pipelining
    Using Oracle's SDO_NN Operator - Some examples
    Converting distances and units of measure in Oracle Locator
    Split Sdo_Geometry Linestring at a known point
    Forcing an Sdo_Geometry object to contain only points, lines or areas
    Unpacking USER_SDO_GEOM_METADATA's DIMINFO structure using SQL
    Generating multi-points from single point records in Oracle Spatial
    Object Tables of Sdo_Geometry
    Oracle Locator vs Oracle Spatial: A Reflection on Oracle Licensing of the SDO_GEOM Package
    FAST REFRESHing of Oracle Materialized Views containing Sdo_Geometry columns
    Australian MGA/AMG Zone Calculation from geographic (longitude/latitude) data
    Loading Shapefiles (SHP) into Oracle Spatial
    Oracle Spatial Mapping and Map Rendering Performance Tips
    The significance of sdo_lb/sdo_ub in USER_SDO_GEOM_METDATA: Do I need it?
    Oracle Spatial Forum - Melbourne April 2007
    Layer_GTypes for spatial indexes
    Oracle's SQL/MM Compliant Types
    Tips and Tricks

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All Blog Articles, Data Models and Free Source Code by Simon Greener, The SpatialDB Advisor is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

The significance of sdo_lb/sdo_ub in USER_SDO_GEOM_METDATA: Do I need it?

Thursday May 10 2007 at 11:50

Questions are often raised about the significance of the SDO_LB and SDO_UB fields of the SDO_DIM_ELEMENT structures that define the spatial extent of the dimensions (SDO_DIM_ARRAY) of a table/column in Oracle's metadata tables (accessed via the USER_SDO_GEOM_METADATA and ALL_SDO_GEOM_METADATA views).

The structure of the the ALL_SDO_GEOM_METADATA view is:
SQL> describe ALL_SDO_GEOM_METADATA
 Name                                                                    Null?    Type
 ----------------------------------------------------------------------- -------- -------------------
 OWNER                                                                   NOT NULL VARCHAR2(32)
 TABLE_NAME                                                              NOT NULL VARCHAR2(32)
 COLUMN_NAME                                                             NOT NULL VARCHAR2(1024)
 DIMINFO                                                                          MDSYS.SDO_DIM_ARRAY
 SRID                                                                             NUMBER

An MDSYS.SDO_DIM_ARRAY is an array of MDSYS.SDO_DIM_ELEMENTs as follows:

SQL> describe MDSYS.SDO_DIM_ARRAY
 MDSYS.SDO_DIM_ARRAY VARRAY(4) OF MDSYS.SDO_DIM_ELEMENT
 Name                                                                    Null?    Type
 ----------------------------------------------------------------------- -------- ------------
 SDO_DIMNAME                                                                      VARCHAR2(64)
 SDO_LB                                                                           NUMBER
 SDO_UB                                                                           NUMBER
 SDO_TOLERANCE                                                                    NUMBER

Note, an SDO_DIM_ELEMENT stucture is created for each dimension of the data eg 2 for 2D data, 3 for 3D data etc.

An example is:

  INSERT INTO ALL_SDO_GEOM_METADATA (
   OWNER,
   TABLE_NAME,
   COLUMN_NAME,
   DIMINFO,
   SRID
   ) VALUES (
   'CODESYS',
   'GEODLINE2D',
   'GEOM', 
   MDSYS.SDO_DIM_ARRAY(
      MDSYS.SDO_DIM_ELEMENT('Longitude',-180,180,0.05),
      MDSYS.SDO_DIM_ELEMENT('Latitude' ,-90,90,0.05)),
  8311);

These questions are often raised in the context of spatial indexing and also their use in overloaded functions in Oracle's SDO_GEOM package which can take either an SDO_DIM_ARRAY structure or an tolerance (cf SDO_TOLERANCE) value such as in the following versions of the geometry validation functions:

FUNCTION VALIDATE_GEOMETRY RETURNS VARCHAR2
 Argument Name                  Type                    In/Out Default?
 ------------------------------ ----------------------- ------ --------
 THEGEOMETRY                    SDO_GEOMETRY            IN
 THEDIMINFO                     SDO_DIM_ARRAY           IN
FUNCTION VALIDATE_GEOMETRY RETURNS VARCHAR2
 Argument Name                  Type                    In/Out Default?
 ------------------------------ ----------------------- ------ --------
 THEGEOMETRY                    SDO_GEOMETRY            IN
 TOLERANCE                      NUMBER                  IN

Indexing
When Oracle Spatial predominantly used QuadTree indexing it was necessary to ensure that the area to be tesselated covered the entire contents of the table/column. Thus, one entered in extents to MDSYS.SDO_DIM_ARRAY that were sensible (ie just covered the area) such that the tesselation could occur effectively and efficiently at the chosen tiling level as expressed by SDO_LEVEL in the PARAMETERS clause of the spatial index creation statement.

If your MDSYS.SDO_DIM_ARRAY SDO_LB/SDO_UBs do not cover the area to be indexed then when you try to create a Quad Tree index with a statement like this:

CREATE INDEX projline2d_geom 
          ON projline(geom) 
          INDEXTYPE IS mdsys.spatial_index 
          PARAMETERS('SDO_LEVEL=8');

You will get this error if the extent of the data in projline2d(geom) includes data outside of the extent recorded in the sdo_dim_array structure:

SQL Error: ORA-29855: error occurred in the execution of ODCIINDEXCREATE routine
ORA-13249: internal error in Spatial index: [mdidxrbd]
ORA-13249: Error in Spatial index: index build failed
ORA-13206: internal error [Tessellate] while creating the spatial index
ORA-13249: Error in spatial index: [mdpridxtessellate]
ORA-13200: internal error [ROWID:AAAPofAAJAAAPNIAAA] in spatial indexing.
ORA-13019: coordinates out of bounds
ORA-06512: at "MDSYS.SDO_INDEX_METHOD_9I", line 7
ORA-06512: at line 1
29855. 00000 -  "error occurred in the execution of ODCIINDEXCREATE routine"

Now RTree indexing does not require a definition of the entire extent of the area to be indexed as the indexing is based on the MBR of individual sdo_geometries and not the regular tesselation of a defined space.

So, nowadays, where RTree indexing is used (and is the recommended spatial indexing method since Oracle Spatial 9.2) the values in the MDSYS.SDO_DIM_ELEMENT's SDO_LB/SDO_UB fields are irrelevant for spatial indexing. So, if one rebuilt the above index using RTree indexing the index would be created:

CREATE INDEX projline2d_geom 
          ON projline(geom) 
          INDEXTYPE IS mdsys.spatial_index 
          PARAMETERS('sdo_indx_dims=2, layer_gtype=MULTILINE');
So what is the use of putting values into these fields when using RTree indexing? Geospatial practitioners tend to use the SDO_DIM_ARRAY to define the extent of the data because some GIS packages do actually use it for "Zoom to Extent" type operations (which would be far faster than SELECT SDO_AGGR_MBR(geom) FROM table!).

Use in Overloaded Functions
Now that cleans up the sdo_lb/sdo_ub elements of the sdo_dim_array structure. But what about tolerance vs MDSYS.SDO_DIM_ARRAYy using in functions?

Now, I tend to avoid hardcoding tolerance values in queries that involve the tolerance parameter (and not the MDSYS.SDO_DIM_ARRAY form) unless it is different from the SDO_TOLERANCE value in the SDO_DIM_ARRAY). Where the tolerance is the same, I always use the MDSYS.SDO_DIM_ARRAY form as it is easier to use in queries.

Compare this:

SELECT mdsys.sdo_geom.validate_geometry(a.geom,asgm.diminfo)
  FROM all_sdo_geom_metadata asgm,
       projline2d a
 WHERE asgm.owner = 'CODESYS'
   AND asgm.table_name = 'PROJLINE2D' 
   AND asgm.column_name = 'GEOM';

To this:

SELECT mdsys.sdo_geom.validate_geometry(a.geom,b.sdo_tolerance)
  FROM (SELECT t.sdo_tolerance
          FROM all_sdo_geom_metadata asgm,
               TABLE(asgm.diminfo) t
         WHERE asgm.owner = 'CODESYS'
           AND asgm.table_name = 'PROJLINE2D' 
           AND asgm.column_name = 'GEOM' 
           AND t.sdo_dimname = 'X' 
        ) b,
        projline2d a;

And I think you can see why!

I hope this explanation is of some use.

If you want to learn more about spatial indexing click here

regards Simon

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Comment [5]

It’s very intresting. I admire you because it’s briliant artice

— Adaddm · 23 September 2007, 10:24 · #

HI,

How can get list spatial enabled tables only ?

Thanks and Regards,

ven

— Venkat · 30 July 2010, 09:02 · #

Venkat,

> How can get list spatial enabled tables only ?

Try:

<code id=“source_code”><pre>
SELECT owner, table_name, column_name FROM all_tab_columns WHERE data_type = ‘SDO_GEOMETRY’;
</pre></code>

regards
Simon

Simon Greener · 30 July 2010, 09:10 · #

Sir,

I have several records of polygon co-ordinates ( 4 points) . I want to check about the overlapping area of the polygon . please help me.

— Sanjeev Sangwan · 30 June 2014, 18:14 · #

Sanjeev,
Look at sdo_union, sdo_difference etc on the sdo_from package.
Simon

— Simon Greener · 30 June 2014, 20:33 · #