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Current Oracle Spatial Blog Articles

    Using Oracle's ST_GEOMETRY type hierarchy with SDO_GEOMETRY: ST_PointN and ST_NumPoints
    Making Sdo Geometry Metadata
    SC4O Test log
    The Frontage Problem: Creating references from land parcel street frontage boundary to point in street
    Scheduling the Export of Spatial Data in Oracle to a Shapefile each night
    Oracle CENTROID package update
    Book: "Applying And Extending Oracle Spatial"
    Create Polygons and Linestrings From Bearings And Distances (COGO)
    Simple Implementation Of Travelling Salesman Problem
    ST_Densify for Object PLSQL
    PLSQL ST_AsEWKT and ST_FromWKT Functions For Oracle (any version)
    Useful Package of Wrapper Functions for Sdo_Util.AffineTransforms
    GeoRaptor 4.x Update 2 (Project has Stalled)
    Tip: Drop that Spatial Index!
    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
    Function That Returns a Compass Point From a Whole Circle Bearing
    Playing around with Centroids by using different seed values
    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
    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
    Compute Location from known Lat/Long point using delta easting and northing in miles
    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
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    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
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    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
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    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
    Free version of sdo_length
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    String Tokenizer for Oracle
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    Oracle Spatial DISJOINT search/filtering
    Creating SDO_Geometry from geometric data recorded in the columns of a table
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    GEOMETRY_COLUMNS for Oracle Spatial
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    Spatial Sorting of Data via Morton Key
    Swapping Ordinates in an SDO_GEOMETRY object
    New To_3D Function
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    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
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    Generating random point data
    Implementing an Affine/ST_Affine function for Oracle Spatial
    Implementing a Scale/ST_Scale function for Oracle Spatial
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    Fixing failed spatial indexes after import using data pump
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    Using Oracle's SDO_NN Operator - Some examples
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    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
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    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:
 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:

 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:

   ) VALUES (
      MDSYS.SDO_DIM_ELEMENT('Latitude' ,-90,90,0.05)),

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:

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

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 

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 · #


How can get list spatial enabled tables only ?

Thanks and Regards,


— Venkat · 30 July 2010, 09:02 · #


> How can get list spatial enabled tables only ?


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


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


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 · #

Look at sdo_union, sdo_difference etc on the sdo_from package.

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