How to get the gridZone letter?

[nnhubbard]

Is there a way to calculate what the grideZone letter would be? E.g. 32U or 10T. How can we get the U or T?

[palmerc]

Calculate? No. Or I should say that it's possible to calculate most of the zones but since some of them are distorted for strategic reasons you'll need to have a few that are looked up. You will definitely want to unit test for that

…

On 2 May 2017, at 18:37, Nic Hubbard ***@***.***> wrote: Is there a way to calculate what the grideZone letter would be? E.g. 32U or 10T. How can we get the U or T? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[nnhubbard]

I guess my question should have been. How are other UTM converters doing it?

[palmerc]

I'm not sure.

…

On 2 May 2017, at 19:14, Nic Hubbard ***@***.***> wrote: I guess my question should have been. How are other UTM converters doing it? — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[nnhubbard]

I wrote this up and seems to be what I am needing:

+ (NSString *)UTMlatZoneForCoordinates:(CLLocationCoordinate2D)coordinate {
    
    NSString *DigraphLetrsE = @"ABCDEFGHJKLMNPQRSTUVWXYZ";
    int latz = 0;//Latitude zone: A-B S of -80, C-W -80 to +72, X 72-84, Y,Z N of 84
    double latd = coordinate.latitude;
    
    if (latd > -80 && latd < 72) {
        latz = floor((latd + 80)/8)+2;
    }
    if (latd > 72 && latd < 84) {
        latz = 21;
    }
    if (latd > 84){
        latz = 23;
    }
    
    char letter = [DigraphLetrsE characterAtIndex:latz];
    return [NSString stringWithFormat:@"%c", letter];
    
}

[palmerc]

So you won't special case Norway and Svalbard

…

On 2 May 2017, at 23:04, Nic Hubbard ***@***.***> wrote: I wrote this up and seems to be what I am needing: + (NSString *)UTMlatZoneForCoordinates:(CLLocationCoordinate2D)coordinate { NSString *DigraphLetrsE = @"ABCDEFGHJKLMNPQRSTUVWXYZ"; int latz = 0;//Latitude zone: A-B S of -80, C-W -80 to +72, X 72-84, Y,Z N of 84 double latd = coordinate.latitude; if (latd > -80 && latd < 72) { latz = floor((latd + 80)/8)+2; } if (latd > 72 && latd < 84) { latz = 21; } if (latd > 84){ latz = 23; } char letter = [DigraphLetrsE characterAtIndex:latz]; return [NSString stringWithFormat:@"%c", letter]; } — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[nnhubbard]

Norway is 32V and that seems to be working correctly. What should I be doing different?

[palmerc]

Put in the lat/long for Bergen

…

Sent from my iPhone

On 3 May 2017, at 00:00, Nic Hubbard ***@***.***> wrote: Norway is 32V and that seems to be working correctly. What should I be doing different? — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[palmerc]

Here's an illustration http://www.geo.uib.no/eworkshop/uploads/Main/utm-zones-small.png

…

On 3 May 2017, at 07:53, Cameron Lowell Palmer ***@***.***> wrote: Put in the lat/long for Bergen Sent from my iPhone > On 3 May 2017, at 00:00, Nic Hubbard ***@***.***> wrote: > > Norway is 32V and that seems to be working correctly. What should I be doing different? > > — > You are receiving this because you commented. > Reply to this email directly, view it on GitHub, or mute the thread. >