The spatial functionality is hugely standards based. There spatial standards are well established what this means is that there are many methods to support the standards. One of the areas that you will see this is the creation of spatial data.

To create an instance of a spatial type you have many many options, most use the methods on the base types, i.e. geometry::STGeomFromText.

This is the set of ways of creating a point,

declare @p geometry;

set @p = geometry::Point(10,10,0);

set @p = geometry::STGeomFromText('POINT(10 10)',0);

set @p = geometry::STPointFromText('POINT(10 10)',0);

set @p = geometry::STPointFromWKB(0x010100000000000000000024400000000000002440,0);

set @p = geometry::GeomFromGml('<Point xmlns="http://www.opengis.net/gml"><pos>10 10</pos></Point>',0);

set @p = geometry::Parse('POINT(10 10)');

set @p = 'POINT(10 10)';

select @p

Only the point sub type has its own specific method geometry::Point. This I guess is because the attributes are well defined. You have one X, one Y and a SRID (Spatial Reference ID), where as the other types you have many Xs and many Ys.

Let me explain a few of these.

The STGeom... and STPoint... are the same expect the later verifies that the geometry you pass in is a Point.

The ..Text methods use the Well-Known Text (WKT) format as input and the ...WKB use the Well-Known Binary (WKB) format. You can use the STAsText method to get the text (WKT) representation of a variable and STAsBinary to find the binary (WKB) represenation

The GeomFromGml is an extension to the methods specified in the OGC and uses the Geography Markup Language (A subset for SQL Server) as input. You can use the AsGml method to get the GML representation . I would personally avoid GML representations due to the bulkiness of XML and overhead or associated processing.

Note: In BOL the method is GeomFromGML. This is incorrect only GeomFromGml works (notice the case of GML) this is consistent with the AsGml method, but contrary to the WKB methods. Who knows what CTP6 or RTM will bring.

You will undoubtedly see most examples using the text based methods because they are more readable. However on on doing some testing it seems the binary methods are quicker (in some tests twice a quick). This makes some sense as each point coordinate can be read as a single entity (8 byte float) where as the text representation has to be read character by character and then creating the value once a boundary (space, comma or bracket) has been reached.

It is also easier to create binary values in TSQL