Create Geometry/Geography Field from Latitude & Longitude Fields (Sql Server)

Create Geometry/Geography Field from Latitude & Longitude fields (SQL Server)

  SELECT  *, 
          geography::STGeomFromText('POINT(' + 
                CAST([Longitude] AS VARCHAR(20)) + ' ' + 
                CAST([Latitude] AS VARCHAR(20)) + ')', 4326) as GEOM,

          geography::Point([Latitude], [Longitude], 4326) as SAME_GEOM

  FROM view_name 
  WHERE (latitude <> 0) AND (longitude <> 0)

SQL Server - From longitude and latitude to geometry data type

You have a geometry, which stores a shape in Euclidean geometry, and you want to associate a point on the globe, represented by a latitude and longitude, with it, to see if it is inside. This won't work, due to the way SQL stores the data. You probably need to use Geography data types to check this - Latitude and longitude are points on a sphere (Actually geodetic data, since the earth is not quite a sphere.)

For more information on why they are different, see this explanation from microsoft. Also this answer on stackoverflow: GEOMETRY and GEOGRAPHY difference SQL Server 2008

To convert your data from geometry to geography, try:
Geography::STGeomFromText(cast(GeomCol as varchar(max)), 4326)

Then you can use the STIntersects method, documented by microsoft here.

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

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;

How to create calculated Geometry column that ignores NULL values in SQL Server

Try filtering the values first. Something like this:

ALTER TABLE Sites 
 ADD Geo2 AS IIF(Latitude  IS NOT NULL AND Longitude IS NOT NULL, [geography]::Point(Longitude,Latitude,4326), NULL)

Group by value and create geography polyline from points (latitude and longitude) for each group in T-SQL

From SQL Server 2017+ you could use:

SELECT geography::STLineFromText('LINESTRING(' + 
         STRING_AGG(CONCAT(Longitude, ' ' ,Latitude), ',') 
         WITHIN GROUP(ORDER BY SortOrder) + ')' , 4326) AS geometry
      ,SensorId
FROM dbo.LongAndLats
GROUP BY SensorId
HAVING COUNT(*) > 1;

DBFiddle Demo

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I've tried using a db_cursor but I get a separate result set for each group

Please avoid cursors, end each line with semicolon and stop using:

SELECT @BuildString = COALESCE(@BuildString + ',', '') 
       + CAST([Longitude] AS NVARCHAR(50)) + ' ' + CAST([Latitude] 
        AS NVARCHAR(50))
FROM [LongAndLats]
WHERE SensorID = @SensorID
ORDER BY SortOrder;  

Construct above may look ok, but it could lead to undefined behaviour. More info: nvarchar concatenation / index / nvarchar(max) inexplicable behavior

EDIT:

SQL Server 2012 version:

SELECT geography::STLineFromText('LINESTRING(' 
      + STUFF(
             (SELECT ',' + CONCAT(Longitude, ' ' ,Latitude) 
              FROM dbo.LongAndLats t2
              WHERE t1.SensorId = t2.SensorId 
              ORDER BY SortOrder
              FOR XML PATH (''))
             , 1, 1, '')
       + ')' 
       , 4326) AS geometry, SensorId
FROM dbo.LongAndLats t1
GROUP BY SensorId
HAVING COUNT(*) > 1;

DBFiddle Demo2

EDIT2:

To avoid:

A .NET Framework error occurred during execution of user-defined routine or aggregate "geography":

System.FormatException: 24117: The LineString input is not valid because it does not have enough points. A LineString must have at least two points.

you could add HAVING COUNT(*) > 1;

FINAL EDIT:

If you have "garbage data", just filter it out(or add CHECK constraint on that column):

"Latitude values must be between -90 and 90 degrees"

SELECT geography::STLineFromText('LINESTRING(' 
      + STUFF(
             (SELECT ',' + CONCAT(Longitude, ' ' ,Latitude) 
              FROM dbo.LongAndLats t2
              WHERE t1.SensorId = t2.SensorId 
                AND Latitude BETWEEN -90 and 90
                AND Longitude BETWEEN -180 AND 180
              ORDER BY SortOrder
              FOR XML PATH (''))
             , 1, 1, '')
       + ')' 
       , 4326) AS geometry, SensorId
FROM dbo.LongAndLats t1
WHERE Latitude BETWEEN -90 and 90
  AND Longitude BETWEEN -180 AND 180
GROUP BY SensorId
HAVING COUNT(*) > 1;

DBFiddle Demo3

Geometry operations on latitude/longitude coordinates

I post as an answer because as comment is too long

geometry works well to the extent that your intersections are approximable to flat intersections.
the difference between geometry and geography consists in the fact that the former works by hypothesizing to work on plane surfaces the second on spherical surfaces. in the case in which the polygons in question are related to small areas in the order of a few thousand meters geometry works very well. the difference between measured distance by imagining that the points lie on a plane or that the points lie on the earth's sphere is so small as to be negligible. Unlike the question if the points are a few hundred kilometers in this case the distance measured in the plane or on the sphere is very different and proportionally is also the result of the intersection between these areas

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