Convert RT90 into WGS84

Question

Goal:
Gain WGS84 decimal to locate some cities in Google Map.

Problem:
I don't know how to convert the value of the RT90 coordinate system into WGS84 in SQL Server.

Answer 1

This page may be of assistance:

Translate coordinates between RT90, WGS84 and SWEREF99 using .NET

Answer 2

in postgis you can use this sql query for RT90(SRID=3021) to WGS84(SRID=4326) :

Select * From ST_Transform(ST_SetSRID(ST_Point(6403554, 6403554), 3021), 4326) as lonlat

---

Select * From ST_X(ST_Transform(ST_SetSRID(ST_Point(6403554, 6403554), 3021), 4326)) as
    lon, ST_Y(ST_Transform(ST_SetSRID(ST_Point(6403554, 6403554), 3021), 4326)) as lat 

beside this you can check out this REST-service which converts coordinates between RT90 (Rikets Triangelnät or Swedish Grid) and WGS84 decimal.

for example:

https://loceo.se/api/wgs84?x=6403550&y=1271824

{
  provider:[
    "Loceo",
    "WGS84"
  ],
  geometry:{
    type:"Point",
    coordinates:[
      57.6987586,
      11.97738784
    ]
  }
}

and the last thing is that i want to say, you can use SQL Server Spatial Tools for querying spatial queries...

i hope it helps you....