Help needed for Qmid To bounding box coordinates

[Vogel]

Hi,
Could someone help me to find the relation between U and V from Qmid(level, U, V) and the coordinates (latitude, longitude) from the upper left corner please.

I try something like:
Latitude = (V+2exp(??)) x 360 / 2exp(level) or similar but it seems to work only for low level...

 

[Vogel]

ok, after some search on the forum I found the post that help me much

thx Arno -> http://www.fsdeveloper.com/forum/threads/convert-lat-lon-to-qmid.437367/#post-744620

with that informations, I think I found the right formula... I share with you guys

From QMID (level, U, V) we can found coordinates (latitude, longitude) of the upper left corner with:

Latitude = 90 - (V x 180/2exp(level-1))
Longitude = (U x 240/2exp(level-1)) - 180

don't hesitate to complete or correct this if needed

 

[Vogel]

And if it's correct, may be a function like this in C# could be added to the wiki on BGL & Qmid subject...

public static List<double> GetBoundingCoordinates(int Level, int U, int V)
        {
            var factor = Math.Pow(2, Level - 1);
            var qmidwidth = 240 / factor;
            var qmidheight = 180 / factor;

            // Calc bounding coordinates
            var maxLatitude =  90.0 - V * qmidheight;
            var minLatitude = maxLatitude - qmidheight;
            var minLongitude = U * qmidwidth - 180.0;
            var maxLongitude = minLongitude + qmidwidth;

            return new List<double>() { minLatitude, maxLatitude, minLongitude, maxLongitude };
        }