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Current SQL Server Blog Articles

    STGeometryTypes: Extracting all geometry type string values from complex geometry
    STDensify: Densify (m)LineString or (m)Polygon geometry objects
    STInsertN: Insert single vertex into a geometry
    STUpdateN: Update (replace) a single vertex within a geometry object.
    STUpdate: Replace all points equal to the supplied point with replacement point.
    STDeleteN: Delete single vertex from geometry
    STDelete: Deleting vertices in geometry objects
    STFlipVectors: Normalize direction of linestring vectors
    STConvertToLineString: Extract LineStrings in GeometryCollection to create LineString
    STLine2Cogo: Converting LineStrings to COGO XML
    STCogo2Line: Creating (Multi)LineStrings geometries from COGO XML instructions
    STVectorize: Break Linestring/Polygon elements into 2 point vectors (or 3 point circular curves)
    STScale: Function to Scale a geometry object
    TSQL String Tokenizer Function for SQL Server
    STGeometry2MBR/STGeography2MBR: Compute and return MBR ordinates
    generate_series for SQL Server 2008
    STExtractPolygon: Extract Polygons from result of STIntersection in SQL Server Spatial
    STRound: Function to round ordinates of a SQL Server Spatial geometry object
    STExtract: Extract elements of a geometry object
    STNumRings: Counting number of polygon rings
    STFilterRings: Removing rings from Polygon based on area.
    STMove: Function to Move a geometry object in SQL Server Spatial
    STCentroid*: Alternate Functions for Compute a Centroid
    STRotate: Function to rotate a geometry object in SQL Server Spatial
    STVertices: Wrapper over STDumpPoints
    STMorton: Creating a Morton number Space Key value for grid square
    Gridding a geometry or geography object (SQL Server Denali)
    On hinting spatial indexes
    RandomSearchByExtent: Random Search Procedure (2008 Spatial)
    COGO: Convert DMS String to decimal degrees floating point number.
    COGO: Converting (Google Earth) Formatted Longitude/Latitude points to decimal degrees (SQL Server)
    COGO: Convert Degrees, Minutes and Seconds values to Decimal Degrees
    COGO: DD2DMS Formatting a latitude/longitude decimal degree value
    COGO: Create point from bearing and distance
    COGO: Compute number of vertices required to stroke circle or circular arc
    COGO: Calculating the bearing between two points (SQL Server 2008 Spatial)
    COGO: Compute arc length subtended by angle centre of circle
    COGO: Compute chord length of segment of a circle (arc)
    COGO: Computing Arc To Chord (Arc2Chord) Separation
    COGO: Creating a stroked polygon from a circle's centre x,y and radius
    COGO: Finding centre and radius of a curve defined by three points: FindCircle function
    CheckRadii: Identifying Tight Radius Curves sections within LineString geometry data
    Generating random point data for SQL Server 2008 Spatial
    New Presentation on Active (Searchable) Spatial Metadata for SQL Server 2008 Spatial and FreeText
    STisGeo: Checking if a column in a table or a view is of type geometry or geography
    Vectorising geometry objects in SQL Server 2008
    STMBR2Geometry/STMBR2Geography functions
    Extracting geometry types from geometry/geography objects in SQL Server 2008
    Getting the number of coordinate dimensions of a geometry/geography object in SQL Server 2008
    STDumpPoints: A Function that Dumps the Vertices/Points in a geometry
    toGeography and toGeography Conversion Functions for SQL Server 2008 Spatial
    Write text file with spatial data from SQL Server 2008
    Loading Shapefiles into Geography type column in SQL Server 2008
    Tip #6: Correcting invalid geometries
    Tip #5: Where or where has my little column gone
    Tip #4: What Coordinate System is that?
    Tip #3: What object is that?
    Tip #2: Spatial Indexing and Primary Keys
    Tip #1: SQL Server 2008 "Katmai" - Setting SRIDs



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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.

New Presentation on Active (Searchable) Spatial Metadata for SQL Server 2008 Spatial and FreeText

Thursday June 17 2010 at 09:12

I gave a presentation on some work I did last year for a customer on providing a sophisticated spatial/textual search capability against over 700 tables of spatial data stored in SQL Server 2008 Spatial. The searching combined Spatial and Free Text index based searching.

The basic idea is that the main thing in static spatial metadata (eg ANZLIC) that is of any use in dynamic systems is the Minimum Bounding Rectangle (MBR) of the data. But the problem is that it is static: populated as an after thought to the transactional update of the actual data.

What is needed is dynamic access to MBR data so that primary filtering can be achieved easily (ie my search area is inside/outside the actual extent of the spatial data). Some database vendors do this very well in their spatial index searches, but such searches are also expensive to execute. What one would like is to be able to filter out spatial data based on an efficient search of a single data source.

The only available offering from the Open GeoSpatial Consortium – the GEOMETRY_COLUMNS table (which SQL Server 2008 Spatial does not support) – for the database community doesn’t support MBRs (though Oracle does in its own proprietary metadata).

The presentation shows how a variant of the OGC GEOMETRY_COLUMNS table can be created (with an appropriately standards compliant View) that gives efficient access to the critical MBR data. (This MBR data can be kept up to date with the actual transactional data via appropriate triggers or scheduled tasks.)

The use of the bundled Free Text searching is a clever way to use something provided at no cost to deliver clever end user search requirements:

“To find all spatial objects for whom any field contains a particular piece of text within the current display MBR

See the presentation here

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Comment [2]


This is pretty neat. Never thought to create a geometry_columns to get ogr2ogr work.

You’ve mentioned that with oracle spatial too as I recall.

This comes up every so often in discussions people wanting to load data with ogr2ogr and using SQL Server 2008 / Oracle spatial etc. It would be really nice to see a write up of the details of that.

Regina 18 June 2010, 11:28 #


The work with GEOMETRY_COLUMNS and ogr2ogr was rather fun. In the end I got ogr2ogr working generating Mapinfo native TAB files with styling. Very cool.

However, loading is another question. One can use ogr2ogr to load the data but only as WKB or WKT. You then have to run SQL Server 2008 Spatial functions to generate an STGeometry from the loaded WKB/WKT. The new generated data is, of course, written in to another geometry column. One can do this via a second batch script or manual processing but most people was a tool that does everything…..

I will blog on this at some stage.


Simon 20 June 2010, 08:59 #