这是我的代码.
Create Table [dbo].[MajorCities]
(
[CityID] int Identity(1,1),[CityName] varchar(60),[Latitude] float,[Longitude] float,GeoRef Geography
)
INSERT INTO dbo.[MajorCities] values
('New Delhi,India',28.6,77.2,null),('Paris,France',48.86667,2.3333,('Rio de Janeiro,Brazil',-22.9,-43.23333,('Sydney,Australia',-33.88306,151.21667,('New York City,USA',40.78333,-73.96667,null)
select * from [MajorCities]
UPDATE [dbo].[MajorCities]
SET [GeoRef] = geography::STPointFromText ('POINT (' + CAST ([Longitude] AS VARCHAR (20)) + ' ' +
CAST ([Latitude] AS VARCHAR (20)) + ')',4326)
我想找到KM中两个位置之间的距离.
请帮我.
谢谢.
解决方法
如果你有纬度和经度的度数(就像你的表中一样),那么你可以使用以下功能：
CREATE FUNCTION dbo.DictanceKM(@lat1 FLOAT,@lat2 FLOAT,@lon1 FLOAT,@lon2 FLOAT)
RETURNS FLOAT
AS
BEGIN
RETURN ACOS(SIN(PI()*@lat1/180.0)*SIN(PI()*@lat2/180.0)+COS(PI()*@lat1/180.0)*COS(PI()*@lat2/180.0)*COS(PI()*@lon2/180.0-PI()*@lon1/180.0))*6371
END
或者,如果您坚持使用地理类型,则使用方法是：
DECLARE @g geography;
DECLARE @h geography;
SET @g = geography::STGeomFromText('LINESTRING(-122.360 47.656,-122.343 47.656)',4326);
SET @h = geography::STGeomFromText('POINT(-122.34900 47.65100)',4326);
SELECT @g.STDistance(@h);
