How to store longitude & latitude as a geography in sql server 2014?

Question

I have locations in longitude and latitude coordinates. My goal is eventually to be able to select all rows from myTable Where distance is less than 2km.

1. Ho

Answer 1

You can convert lat and long to a point and save it in table.

Declare @geo Geography, @Lat varchar(10), @long varchar(10)

SET @Lat = '34.738925' SET @Long = '-92.39764'

SET @geo= geography::Point(@LAT, @LONG, 4326)

Answer 2

Addition to the above Answer @ughai

Adding a column

 ALTER TABLE [dbo].[Landmark]
 ADD [GeoLocation] GEOGRAPHY
 GO

Convert the Longitude and latitudes to Geography

UPDATE [dbo].[Landmark]
SET [GeoLocation] = geography::STPointFromText('POINT(' + CAST([Longitude] 
AS VARCHAR(20)) + ' ' + 
                CAST([Latitude] AS VARCHAR(20)) + ')', 4326)
GO

Finding Places in the radius of 2kms

DECLARE @Origin GEOGRAPHY,
    -- distance defined in meters
    @Distance INTEGER = 2000;        


 SET @Origin = GEOGRAPHY::STGeomFromText('POINT(17.482477 78.546871)', 4326);

 -- return all rows from events in 2km radius
SELECT *,GeoLocation.STDistance(@Origin) Distance FROM dbo.Locations WHERE @Origin.STDistance(GeoLocation) <= @Distance;

it worked for me to get the places within the distance

Answer 3

How can i use the longitute and latitute to store location within a geography column?(because it's supposed to be only one geographic point not two right? not one for longitute and one for latitute?)

You can use geography::STPointFromText / geography::Point to store longitude and latitude in a geography datatype.

SELECT geography::STPointFromText('POINT(' + CAST([Longitude] AS VARCHAR(20)) + ' ' + CAST([Latitude] AS VARCHAR(20)) + ')', 4326)

or

SELECT geography::Point(Latitude, Longitude , 4326)

Reference Link:

Update Geography column in table

Now that I've got the geography points, how can i select all the rows within a specific distance(in my case 2km)?

You can use STDistance like this.

DECLARE @g geography;
DECLARE @h geography;
SET @g = geography::STGeomFromText('POINT(-122.35900 47.65129)', 4326);
SET @h = geography::STGeomFromText('POINT(-122.34720 47.65100)', 4326);
SELECT @g.STDistance(@h);

Reference Link:

Distance between two points using Geography datatype in sqlserver 2008?

Insert Query

DECLARE @GeoTable TABLE 
(
    id int identity(1,1),
    location geography
)
--Using geography::STGeomFromText
INSERT INTO @GeoTable 
SELECT geography::STGeomFromText('POINT(-122.35900 47.65129)', 4326)

--Using geography::Point
INSERT INTO @GeoTable 
SELECT geography::Point(47.65100,-122.34720, 4326);

Get Distance Query

DECLARE @DistanceFromPoint geography
SET @DistanceFromPoint =  geography::STGeomFromText('POINT(-122.34150 47.65234)', 4326);

SELECT id,location.Lat Lat,location.Long Long,location.STDistance(@DistanceFromPoint) Distance
FROM @GeoTable;

Answer 4

In working with GeoPoints in sprocs and selects, it became tiring to always compute the GeoPoint so instead I found it convenient to create a computed column which generates a GeoPoint from the lat/long FLOAT fields when the row is selected.

[GeoPoint]  AS ([geography]::Point([Latitude],[Longitude],(4326))) PERSISTED,