[Qgis-user] Lat Lon Tools question

[C Hamilton]

I should have jumped in on this conversation over the weekend especially
since I am the author of Lat Lon Tools. but all who responded have properly
addressed the problems with UTM and especially with how MGRS got mixed in
with UTM and the confusion with N & S. What Lat Lon Tools provides is the
standard UTM coordinates without the MGRS latitude bands. I have been
considering adding another function that provides the alternative UTM with
MGRS latitude bands.

If anyone has any suggestions on the best way to present these two
different UTM versions that helps to avoid ambiguity, please let me know.

Thanks,

Calvin

On Sat, Feb 6, 2021 at 2:19 PM Eric Sorensen <e.b.s at me.com> wrote:

> As Greg and others point out, I appear to be using the UTM zone term
> inappropriately.  My apologies.
>
> What I am after in my label, is the MGRS flavor that includes the latitude
> band, and agrees with the image shown in this link;
>
> https://docs.qgis.org/3.4/en/_images/utm_zones.png
>
> After you folks successfully educated me on this, I came up with the
> following;
>
> concat(name, ', ',  mgrs_gzd($Y, $X), ' ',   format_number(utm_east( $Y,
> $X), 0), ' ',  format_number(utm_north( $Y, $X), 0))
>
> Which gets me a label like this for the point I originally supplied;
> Park, 13S 384,258 3,974,547
>
> This is how my Garmin GPS displays coordinates of waypoints (sans the
> commas), and how someone would input the point into their gps, after I hand
> them a map I have created in QGIS.  Now to eliminate the commas.
>
> Thank you all for your input,
> es
>
>
> On Feb 6, 2021, at 11:41 AM, Greg Troxel <gdt at lexort.com> wrote:
>
>
> Eric Sorensen <e.b.s at me.com> writes:
>
>  <wpt lat="35.908381976187229" lon="-106.282681999728084">
>    <ele>2262.188964999999826</ele>
>
>
> The labels appear as expected, except one small problem.  I know the
> points are in UTM zone 13S, yet the label shows zone 13N.
>
> Any thoughts on what I am doing wrong.
>
>
> That latitude is north, and in New Mexico.  Why do you think it's zone
> 13S?
>
> <pause to read>
>
> Beware of the confusion between grid zones from MGRS, not technically
> part of UTM, and UTM north/south.  See
>
>
> https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system#Notation
>
> So it seems the UTM output uses S and N -- which is what I would expect
> for straight UTM without a MGRS flavor.
>
> If you moved north, you could be in 13T, from 40-48 degrees, and not
> have this issue, but then you'd have more snow :-)
>
>
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