Go to content Go to navigation and search

Home

Current Oracle Spatial Blog Articles

    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
    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
    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.

Surrounding Parcels

Friday October 17 2008 at 07:27

I had someone contact me the other day and ask:

“I find your articles very helpful and interesting. I was wondering if you can guide me to a link or something that may contain how to figure out surrounding blocks to a given block.”

I am assuming that the person wants to know how to find all polygons that adjoin an adjacent polygon. The following tutorial describes how I would go about this in Oracle Spatial.

First let’s select all parcels that share any sort of boundary with a particular parcel. That is, those that share at a common corner (only) or a common line.

select /*+ORDERED*/ 
       p.gid  as searchGID, 
       p2.gid as surroundingGID
  from parcel p,
       parcel p2
 where p.gid = 2
   and SDO_TOUCH(p2.geometry,p.geometry) = 'TRUE'
 order by p2.gid;

SEARCHGID SURROUNDINGGID
2 1
2 3
2 4
2 5
2 6

Parcels touching a parcel

Now, what if we wanted to select those that shared only a common point or just a common line?

From what I can see of the documentation (“Section 1.8 Spatial Relationships and Filtering” – please let me know if I am wrong) Oracle has implemented Egenhofer’s Nine-Intersection Model (9DIM matrix) for topological relationships. That model does not distinguish between the different forms of relationships like TOUCH (MEET). The Egenhofer 9-intersection model (9DIM matrix) has been extended by Clementini et al (1993) in “A small set of formal topological relationships suitable for end-user interactions” by taking into account the dimensionality of the resultant relationships/intersections. Clementini’s additions would allow me to know when TOUCH between two geometries was 0-D (point) or 1-D (line) or a mix.

SDO_TOUCH covers both point and line sharing but can’t be used to discriminate between the two. I is no other Oracle spatial operator that can help us. I also cannot (yet) think of a combination, executed using a set operator like MINUS that can be used. I validated this thinking via the following SQL.

select /*+ORDERED*/ 
       distinct
       case when p.gid < p2.gid then p.gid else p2.gid end as gid1,
       case when p.gid > p2.gid then p.gid else p2.gid end as gid2,
       sdo_geom.relate(p2.geometry,'DETERMINE',p.geometry,0.05) as result
  from parcel p,
       parcel p2
 where p.gid <> p2.gid
 order by 1;

gid1 gid2 result
1 2 TOUCH
1 3 TOUCH
1 4 DISJOINT
1 5 TOUCH
1 6 DISJOINT
2 3 TOUCH
2 4 TOUCH
2 5 TOUCH
2 6 TOUCH
3 4 DISJOINT
3 5 TOUCH
3 6 DISJOINT
4 5 TOUCH
4 6 TOUCH
5 6 TOUCH

You will notice from the results that everything that surrounds is reported as touches. Not that useful.

We are left, therefore, with having to do a little more heavy-lifting in SQL. We know that the point or line that results from a TOUCH relationship can be discovered via use of an intersection operator like Oracle’s sdo_geom.sdo_intersection.

So, here is one approach coded in SQL:

select i.searchGID, i.surroundingGID
  from (select /*+ORDERED*/ 
               p.gid as searchGID, 
               p2.gid as surroundingGID,
               sdo_geom.sdo_intersection(p2.geometry,p.geometry,0.005) as geom
          from parcel p,
               parcel p2
         where p.gid = 2
           and SDO_TOUCH(p2.geometry,p.geometry) = 'TRUE'
       ) i
 where i.geom.sdo_gtype <> 2001
 order by i.surroundingGID;

SEARCHGID SURROUNDINGGID
2 1
2 4
2 5

Parcels sharing a boundary

Now, sdo_geom.sdo_intersection is a Spatial feature that must be paid for. Is there a method that will work in Locator?

A Locator based method is encapsulated in the following SQL snippet. Note that the approach here is to join the parcel returned by the search to the search parcel via their vertices! The distinct is put in because the first/last vertex of a polygon is the same and so could skew the results.

select i.searchGID, i.surroundingGID, count(*) as vertexCount
 from (select /*+ORDERED*/ 
              distinct
              p.gid  as searchGID, 
              p2.gid as surroundingGID,
              v.x,v.y
         from parcel p,
              table(mdsys.sdo_util.GetVertices(p.geometry)) v,
              parcel p2,
              table(mdsys.sdo_util.GetVertices(p2.geometry)) v2
        where p.gid = 2
          and SDO_TOUCH(p2.geometry,p.geometry) = 'TRUE'
          and ( v2.x = v.x 
                and 
                v2.y = v.y )
          order by 2
       ) i
 group by i.searchGID, i.surroundingGID
 order by i.surroundingGID

searchGID surroundingGID vertexCount
2 1 2
2 3 1
2 4 2
2 5 2
2 6 1

Thus, those that return a vertexCount of 1 must join only at the corners, whereas those with a higher count must share a common boundary line. So, to find these parcels the complete SQL is:

select i.searchGID, i.surroundingGID
  from (select /*+ORDERED*/ 
               distinct
               p.gid  as searchGID, 
               p2.gid as surroundingGID,
               v.x,v.y
          from parcel p,
               table(mdsys.sdo_util.GetVertices(p.geometry)) v,
               parcel p2,
               table(mdsys.sdo_util.GetVertices(p2.geometry)) v2
         where p.gid = 2
           and SDO_TOUCH(p2.geometry,p.geometry) = 'TRUE'
           and ( v2.x = v.x 
                 and 
                 v2.y = v.y )
         order by 2
       ) i
 group by i.searchGID, i.surroundingGID
 having count(*) > 1
 order by i.surroundingGID;

searchGID surroundingGID
2 1
2 4
2 5

Which is the same result as the on that used sdo_intersection above.

I hope this is useful to someone out there!

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 [6]

This helps alot!!!!!..thank you very much

— Nolan Porther · 9 April 2012, 19:14 · #

Simon,

I have extracted vertices of surrounding polygons by using above code, but there are some duplicates.

How to extract the unique points (vertices) of surrounding polygons along with polygon id and vertex id so that linestrings can be formed

thanks
masood

— masood · 27 June 2012, 12:04 · #

Mansood,

Don’t forget that the first and last vertex of a polygon’s ring in an sdo_geometry object is duplicated. So if the polygon starts at a shared corner with another polygon then you will get duplicates.

But I don’t understand your use-case. This one is about finding the surrounding parcels where they touch at a point.

I can show you how to get the shared lines without needing to process the points.

Is that what you want?

If you send me test data I will construct and article on this for you.

regards
Simon

— Simon Greener · 27 June 2012, 12:19 · #

Hi Simon, I want to ask about a problem I have, I have a table in oracle with a rural parcels and I have been determined for each of the parcels, if within 1000 meters there is another rural parcels. You could give me one example.?

THANKS

— Javier · 19 December 2012, 19:28 · #

One again.. you’ve solved my problem !!
Thanks a million for all of your posts !!!

Cheers,
jb

— Jean-Bernard Gariépy · 16 January 2013, 15:16 · #

thanks about code of second figuer
but i want acode that know the direction of three shapes (1 , 4 , 5) for shape 2
that indicate which of them in north , south , east and west
thanks
wael

— wael · 26 February 2013, 10:52 · #