*********************************************************** ** 0: Contents *********************************************************** 1: Introduction 2: Installation 3: Features *********************************************************** ** 1: Introduction *********************************************************** This project is a collection of tools for use with the spatial types in SQL Server. This project does not provide an end-user application, but rather a set of reusable functions which applications can make use of. Development of this package is hosted at GitHub: http://www.github.com/Microsoft/SQLServerSpatialTools. Source is available at this site. This package is licensed under the Microsoft public license. See http://www.github.com/Microsoft/SQLServerSpatialTools/blob/master/License.txt or the included License.txt file for details. *********************************************************** ** 2: Installation *********************************************************** This package contains a single assembly, SQLSpatialTools.dll This assembly can be included and used directly from a .NET application, or can be registered and used from within SQL Server. Scripts for registering and unregistering the functionality in SQL Server are included in the SQL Scripts directory. Detailed Steps: To Register: 1) Note the path to the SQLSpatialTools.dll file. 2) Edit the Register.sql file in the SQL Scripts directory: a) Insert the name of the database you are registering the functionality to where indicated at the beginning of the script. b) Insert the path to the SQLSpatialTools.dll file where indicated at the beginning of the script. 3) Execute the script on your SQL Server instance. To Unregister: 1) Edit the Unregister.sql file in the SQL Scripts directory and insert the name of the database use are unregistering the functionality from where indicated at the beginning of the script. 2) Execute the script on your SQL Server instance. *********************************************************** ** 3: Features *********************************************************** Scripts ------- Several scripts are included in the SQL Scripts directory. These include scripts for registering and unregistering all of the following components, as well as several examples of their use. Functions --------- These static methods, implemented in the class Functions, can both be registered in SQL Server and used through T-SQL, as well as be used directly from the CLR: bool IsValidGeographyFromGeometry(SqlGeometry geometry) Check if an input geometry can represent a valid geography without throwing an exception. This function requires that the geometry be in longitude/latitude coordinates and that those coordinates are in correct order in the geometry instance (i.e. latitude/longitude not longitude/latitude). This function will return false (0) if the input geometry is not in the correct latitude/longitude format, including a valid geography SRID. bool IsValidGeographyFromText(string inputWKT, int srid) Check if an input WKT can represent a valid geography. This function requires that the WTK coordinate values are longitude/latitude values, in that order and that a valid geography SRID value is supplied. This function will not throw an exception even in edge conditions (i.e. longitude/latitude coordinates are reversed to latitude/longitude). SqlGeography MakeValidGeographyFromGeometry(SqlGeometry geometry) Convert an input geometry instance to a valid geography instance. This function requires that the WKT coordinate values are longitude/latitude values, in that order and that a valid geography SRID value is supplied. SqlGeography MakeValidGeographyFromText(string inputWKT, int srid) Convert an input WKT to a valid geography instance. This function requires that the WKT coordinate values are longitude/latitude values, in that order and that a valid geography SRID value is supplied. SqlGeography ConvexHullGeography(SqlGeography geography) Computes ConvexHull of input geography and returns a polygon (unless all input points are colinear). SqlGeography ConvexHullGeographyFromText(string inputWKT, int srid) Computes ConvexHull of input WKT and returns a polygon (unless all input points are colinear). This function does not require its input to be a valid geography. This function does require that the WKT coordinate values are longitude/latitude values, in that order and that a valid geography SRID value is supplied. SqlGeography DensifyGeography(SqlGeography g, double maxAngle) Returns a geography instance equivalent to its input, but with no two consecutive points spaced more than maxAngle apart. SqlGeography InterpolateBetweenGeog(SqlGeography start, SqlGeography end, double distance) Takes start and end geography points and returns a new point that is a given distance from the start toward the end. SqlGeometry InterpolateBetweenGeom(SqlGeometry start, SqlGeometry end, double distance) Takes start and end geometry points and returns a new point that is a given distance from the start toward the end. SqlGeography LocateAlongGeog(SqlGeography g, double distance) Takes a geography linestring and finds the point a given distance along it. SqlGeometry LocateAlongGeom(SqlGeometry g, double distance) Takes a geometry linestring and finds the point a given distance along it. SqlGeometry ShiftGeometry(SqlGeometry g, double xShift, double yShift) Takes a geometry instance and shifts if by a given X and Y amount. SqlGeometry VacuousGeographyToGeometry(SqlGeography toConvert, int targetSrid) A special case of the equirectangular projection, taking each point (lat,long) --> (y, x). SqlGeography VacuousGeometryToGeography(SqlGeometry toConvert, int targetSrid) The inverse of the VacuousGeographyToGeometry projection. Types ----- These types can be registered in SQL Server or used directly through the CLR. SqlProjection This class provides an extensible access point to various projections and inverse projections. See the file projection_example.sql for a sample of its use. Currently supported projections are: * Albers Equal Area * Equirectangular * Lambert Conformal Conic * Mercator * Oblique Mercator * Tranverse Mercator * Gnomonic AffineTransform This provides general affine transformations. See the example transform_example.sql for a sample of its use. Aggregates ---------- While implemented as classes, aggregates are essentially functions that take a collection of inputs to a single result. GeographyUnionAggregate This aggregate finds the union of a set of geographies with an optional additional buffer. GeometryEnvelopeAggregate This aggregate finds the envelope that contains a set of input geometries.