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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.

STLine2Cogo: Converting LineStrings to COGO XML

Tuesday June 26 2018 at 16:58

KeywordsLineString COGO bearing distance export XML

Function to create Xml document containing Cogo bearing and distance instructions from an existing linestring.

I have just written a useful function for my new package of TSQL functions for SQL Server Spatial called STLine2Cogo which converts (exports) a (Multi)LineString into a set of instructions (bearing, distances etc) that can be shared with other COGO functions.

The function’s documentation can be seen at this STLine2Cogo

Here are some examples:

  1. -- Write 2D with DMS string bearings
  2. SELECT [cogo].[STLine2Cogo] (
  3.           geometry::STGeomFromText('LINESTRING (10 10, 8.163 17.034, 158.755 35.432, 157.565 25.108)',0),
  4.           CHAR(176),CHAR(39),'"')
  5. GO
  1. <Cogo srid="0">
  2.   <Segments>
  3.     <Segment>
  4.       <MoveTo>POINT (10 10)</MoveTo>
  5.       <DegMinSec> 345°21'48.75"</DegMinSec>
  6.       <Distance>7.26992</Distance>
  7.     </Segment>
  8.     <Segment>
  9.       <DegMinSec>  83° 2'4.652"</DegMinSec>
  10.       <Distance>151.712</Distance>
  11.     </Segment>
  12.     <Segment>
  13.       <DegMinSec> 186°34'30.73"</DegMinSec>
  14.       <Distance>10.3924</Distance>
  15.     </Segment>
  16.   </Segments>
  17. </Cogo>
  1. -- Write decimal degrees bearings and maintain 3D.
  2. SELECT [cogo].[STLine2Cogo] (
  3.           geometry::STGeomFromText('LINESTRING (10 10 -1, 8.163 17.034 0, 158.755 35.432 2, 157.565 25.108 5)',0),
  4.       NULL,NULL,NULL)
  5. GO
  1. <Cogo srid="0">
  2.   <Segments>
  3.     <Segment>
  4.       <MoveTo>POINT (10 10 -1)</MoveTo>
  5.       <Bearing>345.364</Bearing>
  6.       <Distance>7.26992</Distance>
  7.       <DeltaZ>1</DeltaZ>
  8.     </Segment>
  9.     <Segment>
  10.       <Bearing>83.0346</Bearing>
  11.       <Distance>151.712</Distance>
  12.       <DeltaZ>2</DeltaZ>
  13.     </Segment>
  14.     <Segment>
  15.       <Bearing>186.575</Bearing>
  16.       <Distance>10.3924</Distance>
  17.       <DeltaZ>3</DeltaZ>
  18.     </Segment>
  19.   </Segments>
  20. </Cogo>

The following code converts the shown LineString to a table of COGO values.

  1. SELECT [cogo].[STLine2COGO](geometry::STGeomFromText('LINESTRING (382.875 -422.76, 381.038 -415.726, 531.63 -397.328, 530.44 -407.652, 543.796 -406.729, 542.673 -415.759, 603.73 -415.063, 603.693 -403.377, 614.665 -404.601, 612.239 -376.561, 617.793 -375.878)',28356),
  2.                             NULL,NULL,NULL) AS t
  3. GO

The result is:

  1. <Cogo srid="28356">
  2.   <Segments>
  3.     <Segment>
  4.       <MoveTo>POINT (382.875 -422.76)</MoveTo>
  5.       <Bearing>345.364</Bearing>
  6.       <Distance>7.26992</Distance>
  7.     </Segment>
  8.     <Segment>
  9.       <Bearing>83.0346</Bearing>
  10.       <Distance>151.712</Distance>
  11.     </Segment>
  12.     <Segment>
  13.       <Bearing>186.575</Bearing>
  14.       <Distance>10.3924</Distance>
  15.     </Segment>
  16.     <Segment>
  17.       <Bearing>86.0467</Bearing>
  18.       <Distance>13.3879</Distance>
  19.     </Segment>
  20.     <Segment>
  21.       <Bearing>187.089</Bearing>
  22.       <Distance>9.09956</Distance>
  23.     </Segment>
  24.     <Segment>
  25.       <Bearing>89.3469</Bearing>
  26.       <Distance>61.061</Distance>
  27.     </Segment>
  28.     <Segment>
  29.       <Bearing>359.819</Bearing>
  30.       <Distance>11.6861</Distance>
  31.     </Segment>
  32.     <Segment>
  33.       <Bearing>96.3654</Bearing>
  34.       <Distance>11.0401</Distance>
  35.     </Segment>
  36.     <Segment>
  37.       <Bearing>355.055</Bearing>
  38.       <Distance>28.1448</Distance>
  39.     </Segment>
  40.     <Segment>
  41.       <Bearing>82.9893</Bearing>
  42.       <Distance>5.59584</Distance>
  43.     </Segment>
  44.   </Segments>
  45. </Cogo>

A final test it to convert a line to Cogo and then create the line from that Cogo.
They should be the same:

  1. WITH line AS (
  2.   SELECT geometry::STGeomFromText('LINESTRING (10 10 -1, 8.163 17.034 0, 158.755 35.432 2, 157.565 25.108 5)',0) AS line
  3. )
  4. SELECT a.line.STEquals(
  5.         [cogo].[STCogo2Line] (
  6.           [cogo].[STLine2Cogo] (a.line,CHAR(176),CHAR(39), '"'),
  7.           3, 2
  8.         )) AS isEquals
  9.   FROM line AS a
  10. GO
  11. isEquals
  12. --------
  13. 1

I hope this is of interest to someone.

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