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How are polygons converted to points in MSSQL?
My polygon is being given as points, and being converted to geography. My data has a Shape column that according to MSSQL is stored as geography. In order to get the query to work I’m asking every field to be converted via STAsText – and I think that’s a performance hangup.
How to extract spatial points from a polygon?
I cannot see anywhere where I can extract the points from the Polygon using SQL Server from within a SQL Query? I can evidentally take the whole polygon and then do the rest on the client, but I would rather deal in SQL if possible. Any help appreciated in pointing me in the right direction.
What are the requirements for a polygon in SQL?
A Polygon instance that has an acceptable exterior ring ( LineString) and zero or more acceptable interior rings ( LineString s) The following criteria are needed for a ring ( LineString) to be acceptable. The LineString instance must be accepted. The LineString instance must have at least four points.
Do you need a spatial index in MSSQL?
Firstly, make sure there is a spatial index on the [Shape] column. Secondly, there is no need to call STAsText () in the WHERE clause since that will force each row to convert to string unnecessary (and disqualify the use of any spatial indexes I think).
What is the definition of Geography in SQL Server?
Applies to: SQL Server (all supported versions) Azure SQL Database Returns a geography instance from an Open Geospatial Consortium (OGC) Well-Known Text (WKT) representation augmented with any Z (elevation) and M (measure) values carried by the instance.
What is stpolyfromtext ( geography data type )?
STPolyFromText (geography Data Type) Returns a geography instance from an Open Geospatial Consortium (OGC) Well-Known Text (WKT) representation augmented with any Z (elevation) and M (measure) values carried by the instance.
What are the arguments for the geographypolygon instance?
Arguments. polygon_tagged_text Is the WKT representation of the geographyPolygon instance you wish to return. polygon_tagged_text is an nvarchar(max) expression. SRID Is an int expression representing the spatial reference ID (SRID) of the geographyPolygon instance you wish to return.