[PROJ] Syntax to change projection from UTM to TM

[Javier Jimenez Shaw]

Why +k=0.9996439573 for UTM?
It should be 0.9996, right?

On Fri, 6 Dec 2024, 21:29 Ulises Ibarra via PROJ, <proj at lists.osgeo.org>
wrote:

> Hello, I would like you to please guide me with my following couple of
> questions:
>
> I have a list of coordinates in a UTM Zone 14 North projection, in the
> ITRF2008 datum, I would like to change them to a Transverse Mercator
> projection, in which the central meridian lon_0 coincides in longitude with
> one of the points on my list, point 1: UTM(1, East=479969.231,
> North=2143791.499, Elevation=2274.949) and or in geographic coordinates (1,
> lat=19.388187333, lon=-99.190762728, Elevation=2274.949)
>
> Question: Would it be correct to use the following syntax and parameters?
> Because I am not getting the expected result.:
>
> echo 480037.249 2143783.696 2271.294 | cct +proj=pipeline +step +inv
> +proj=utm +zone=14 +ellps=GRS80 +k=0.9996439573 +step +proj=tmerc
> +lat_0=19.388187333 +lon_0=-99.190762728 +x_0=479969.231 +y_0=2143791.499
> +ellps=GRS80 +k=1
>
> I get the output: 480037.2841   2143783.7685     2271.2940           inf
>
> The correct result should be:   480037.3001 2143783.6901 2271.294
>
> Best regards
>
> Ulises
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