Go to content Go to navigation and search

Home

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

Search

    Browse

RSS / Atom

Email me

textpattern

Creative Commons License
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 Spatial filtering of geometries: The effect of tolerances on relationships

Sunday April 01 2012 at 07:45

Keywordssdo_anyinteract sdo_geom.relate filter tolerance different results relationships
Summary

This article puts some “flesh” on Bryan Hall’s article on Otn “Note on spatial relationships and tolerance” by providing a worked example of the effect that coarse and fine tolerances has on spatial filtering.

The knowledgeable Bryan Hall made a post over on the Oracle Technology Network’s Oracle Spatial Forum reminding users of the “hidden” issues that inform the way Oracle compare’s two geometries when using a secondary filter

Here is the relevant section of the post.

With relationship operators such as sdo_anyinteract that take two parameters for the spatial columns to use for the test. The first must be indexed (a real table), and the second can be indexed, or just a passed or created spatial object. In my cases, both are always indexed, and most spatial items have a very tight tolerance. But for one object, instead of the 0.001 meter tolerance, it had a 0.1 meter tolerance. I didn’t realize that – until I ran the query both ways (using the ORDERED hint) to see which would be quicker for the script – and then came back with a different number of results.

The difference was the order of use in sdo_anyinteract. If the first item listed has a wider tolerance, more results are returned as it is more inclusive. However, if the order is reversed, the more restrictive tolerance is used and you get fewer results.

Let’s look at this in detail.

Some data

  1. -- Rect1
  2. DROP   TABLE rect1;
  3. CREATE TABLE rect1 ( id   INTEGER, geom mdsys.sdo_geometry);
  4. INSERT INTO rect1 (ID,GEOM) VALUES (1,mdsys.sdo_geometry(2003,NULL,NULL,mdsys.sdo_elem_info_array(1,1003,3),mdsys.sdo_ordinate_array(1,1,10,10))); COMMIT;
  5. DELETE FROM user_sdo_geom_metadata WHERE TABLE_NAME = 'RECT1' AND column_name = 'GEOM'; COMMIT;
  6. INSERT INTO user_sdo_geom_metadata (TABLE_NAME,column_name,srid,diminfo) VALUES ('RECT1','GEOM',NULL,mdsys.sdo_dim_array(mdsys.sdo_dim_element('X',0,11,0.05),mdsys.sdo_dim_element('Y',0,11,0.05))); COMMIT;
  7. CREATE INDEX rect1_geom_spdx ON rect1(geom) INDEXTYPE IS mdsys.spatial_index PARAMETERS('sdo_indx_dims=2, layer_gtype=POLYGON');
  8. -- Rect2
  9. DROP   TABLE rect2;
  10. CREATE TABLE rect2 ( id   INTEGER, geom mdsys.sdo_geometry);
  11. INSERT INTO rect2 (ID,GEOM) VALUES (1,mdsys.sdo_geometry(2003,NULL,NULL,mdsys.sdo_elem_info_array(1,1003,3),mdsys.sdo_ordinate_array(10.01,10.01,20,20))); COMMIT;
  12. DELETE FROM user_sdo_geom_metadata WHERE TABLE_NAME = 'RECT2' AND column_name = 'GEOM'; COMMIT;
  13. INSERT INTO user_sdo_geom_metadata (TABLE_NAME,column_name,srid,diminfo) VALUES ('RECT2','GEOM',NULL,mdsys.sdo_dim_array(mdsys.sdo_dim_element('X',10,21,0.0005),mdsys.sdo_dim_element('Y',10,21,0.0005))); COMMIT;
  14. CREATE INDEX rect2 ON rect2(geom) INDEXTYPE IS mdsys.spatial_index PARAMETERS('sdo_indx_dims=2, layer_gtype=POLYGON');

Note that a tolerance of 0.05 is the same as 0.1 and 0.0005 the same as 0.001.

Relationship Operators/Functions and Parameters

Firstly, let’s use a relationship function that takes a tolerance input to show the differences when the tables have two different tolerances.

  1. SELECT SDO_GEOM.RELATE(a.geom,'DETERMINE',b.geom,0.5  /* rect1 tolerance */) AS u1relate,
  2.        SDO_GEOM.RELATE(a.geom,'DETERMINE',b.geom,0.005/* rect2 tolerance */) AS u2relate
  3.   FROM rect1 a,
  4.        rect2 b,
  5.        user_sdo_geom_metadata u1,
  6.        user_sdo_geom_metadata u2
  7.  WHERE ( u1.TABLE_NAME = 'RECT1' AND u1.column_name = 'GEOM' )
  8.    AND ( u2.TABLE_NAME = 'RECT1' AND u2.column_name = 'GEOM' );

Notice that at the coarser RECT1 tolerance of 0.5 the objects touch – which is correct.
But at the finer RECT2 tolerance of 0.005 the objects are disjoint – which is also correct.

So, now what happens if we search as per Bryan’s posting?

Firstly, searching for the RECT2’s geometry which has the finer tolerance:

  1. SELECT /*+ORDERED*/
  2.        a.id, b.id
  3.   FROM rect1 a,
  4.        rect2 b
  5.  WHERE SDO_RELATE(b.geom,a.geom,'mask=anyinteract') = 'TRUE';
  6. -- Results
  7. -- NOTHING ie DISJOINT

And the reverse, searching for RECT1’s geometry which has the coarser tolerance:

  1. SELECT /*+ORDERED*/
  2.        a.id, b.id
  3.   FROM rect2 b,
  4.        rect1 a
  5.  WHERE SDO_RELATE(a.geom,b.geom,'mask=anyinteract') = 'TRUE';
  6. -- Result
  7. ID ID                    
  8. -- --
  9. 1  1

That is, they have an interaction (ie TOUCH).

Assuming that these Oracle secondary filter functions use SDO_GEOM.RELATE to compare two geometries then we seem to have duplicated Bryan’s problem.

Now, let’s repeat this test using one of the “wrapper” secondary filters.

  1. SELECT /*+ORDERED*/
  2.        a.id, b.id
  3.   FROM rect1 a,
  4.        rect2 b
  5.  WHERE SDO_ANYINTERACT(b.geom,a.geom) = 'TRUE';
  6. -- Results
  7. -- NOTHING ie DISJOINT

And the reverse:

  1. SELECT /*+ORDERED*/
  2.        a.id, b.id
  3.   FROM rect2 b,
  4.        rect1 a
  5.  WHERE SDO_TOUCH(a.geom,b.geom) = 'TRUE';
  6. -- Result
  7. ID ID                    
  8. -- --
  9. 1  1

Which is as expected.

Trouble at Mill

However, SDO_GEOM.RELATE does not perform as expected when on uses the version of
the function with two diminfo parameters:

  1. SELECT SDO_GEOM.RELATE(a.geom,u1.diminfo,'DETERMINE',b.geom,u1.diminfo) AS u11relate,
  2.        SDO_GEOM.RELATE(a.geom,u1.diminfo,'DETERMINE',b.geom,u2.diminfo) AS u12relate,
  3.        SDO_GEOM.RELATE(a.geom,u2.diminfo,'DETERMINE',b.geom,u1.diminfo) AS u21relate,
  4.        SDO_GEOM.RELATE(a.geom,u2.diminfo,'DETERMINE',b.geom,u2.diminfo) AS u22relate
  5.   FROM rect1 a,
  6.        rect2 b,
  7.        user_sdo_geom_metadata u1,
  8.        user_sdo_geom_metadata u2
  9.  WHERE ( u1.TABLE_NAME = 'RECT1' AND u1.column_name = 'GEOM' )
  10.    AND ( u2.TABLE_NAME = 'RECT2' AND u2.column_name = 'GEOM' );
  11. -- Results
  12. U11RELATE U12RELATE U21RELATE U22RELATE
  13. --------- --------- --------- ---------
  14. TOUCH     TOUCH     TOUCH     TOUCH

Caveat Emptor! (Latin for “Let the buyer beware”)

Hope this helps someone.

Creative Commons License

post this at del.icio.uspost this at Diggpost this at Technoratipost this at Redditpost this at Farkpost this at Yahoo! my webpost this at Windows Livepost this at Google Bookmarkspost this to Twitter

Comment [4]

There is an error in the SQL statement for “Trouble at Mill” which could explain the problem. The last line of the SQL should use the table_name RECT2 instead of RECT1,
i.e., AND ( u2.TABLE_NAME = ‘RECT2’ AND u2.column_name = ‘GEOM’ );

Regards,
Martin

— Martin Gans · 28 June 2012, 07:57 · #

Martin,
Ahhh, missed that.
Well done for “paying attention”!
Thanks, I will fix it.
Simon

— Simon Greener · 28 June 2012, 08:38 · #

How to select all records from a table with oriented point geometries, where Z <> 0
So something like
select p.geometry from points p where p.geometry.Z <> 0.

Example matching record :
select SDO_GEOMETRY(3001, 31370, NULL, SDO_ELEM_INFO_ARRAY(1, 1, 1, 4, 1, 0), SDO_ORDINATE_ARRAY(155395.5199, 121789.6388, -2.33269509664069E-5, 1, 0, 0)) from dual

Example not matching record :
select SDO_GEOMETRY(3001, 31370, NULL, SDO_ELEM_INFO_ARRAY(1, 1, 1, 4, 1, 0), SDO_ORDINATE_ARRAY(155395.5199, 121789.6388, 0, 1, 0, 0)) from dual

— Ivan · 21 October 2016, 01:40 · #

There is a function in my GEOM package called isOrientedPoint that returns 0 if false and 1 if true. Can be used as follows:

with example as (
select SDO_GEOMETRY(3001, 31370, NULL, SDO_ELEM_INFO_ARRAY(1, 1, 1), SDO_ORDINATE_ARRAY(155395.5199, 121789.6388, -0.00000233269509664)) as oPoint from dual
union all
select SDO_GEOMETRY(3001, 31370, NULL, SDO_ELEM_INFO_ARRAY(1, 1, 1, 4, 1, 0), SDO_ORDINATE_ARRAY(155395.5199, 121789.6388, -0.00000233269509664, 1, 0, 0)) as oPoint from dual
union all
select SDO_GEOMETRY(3001, 31370, NULL, SDO_ELEM_INFO_ARRAY(1, 1, 1, 4, 1, 0), SDO_ORDINATE_ARRAY(155395.5199, 121789.6388, 0, 1, 0, 0)) from dual
)
select geom.IsOrientedPoint(a.oPoint.sdo_elem_info) as isOriented
from example a;
ISORIENTED
=========
0
1
1

I hope this is of use.

regards
Simon

— Simon Greener · 22 October 2016, 16:17 · #