Example how to convert coordinates between grids. Swedish Grid to UTM is used as and example here.
The steps are identical to convert State Plane Coordinate System (NAD83/NAD27) to UTM. Or
British Grid to UTM, etc...
Make sure Easting/Northing is selected in the upper left corner.
Select the grid to convert from by clicking .
Browse to "The Earth->Europe->Sweden" and select RT90 2.5gonV. And click "OK".
Or you can simply write RT90 in the "Find" box to search for a grid by name.
Enter a coordinate to convert from RT90 2.5gonV to UTM. Since this is a grid, you must enter Easting and Northing in the boxes.
You can also click on either the left-most map or the middle map.
To read a position from a GPS click "Read position from GPS". (GpsGate must be installed for this feature.)
Make sure Easting/Northing is selected in the upper right corner.
Select the grid to convert to by clicking in the right pane. Again, you will need
to browse to the appropriate region and select the grid. UTM is an international coordinate system, but you must select a local zone.
In this example, we will convert to UTM Zone 32N which is available in Sweden.
Or you can simply write 32N in the "Find" box to search for a grid by name.
Finally, click the right-arrow button or click F12! To convert from UTM to RT90, just click the left-arrow button or F11.