I am having trouble to convert coordinates from UTM to lat/long for a known location. If you ask AI to do the calc for you, it gives you the correct answer but for some reason my R "terra" package code is not returning the same result. The expected lat/long outcome of the X (Easting) = 791423.36, Y (Northing) = 6341151.30 in France (Salindres) should be 44.36 and 4.14.
library(terra)
v <- vect( as.matrix( cbind(791423.36, 6341151.30) ), crs = "EPSG:32631")
v
y <- project(v, "EPSG:4326")
y
the outcome:
class : SpatVector
geometry : points
elements : 1
extent : 791423.4, 791423.4, 6341151, 6341151 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +zone=31 +datum=WGS84 +units=m +no_defs
class : SpatVector
geometry : points
elements : 1
extent : 7.815223, 7.815223, 57.12102, 57.12102 (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs
Using this page as a resource: https://epsg.io/?q=France%20kind%3APROJCRS.
Through some trail and error crs=2154 seems to provide the correct answer.
library(sf)
p1<- st_sfc(st_point(c(791423.36, 6341151.30)), crs=2154)
st_transform(p1, crs=4326)
Geometry set for 1 feature
Geometry type: POINT
Dimension: XY
Bounding box: xmin: 4.143171 ymin: 44.16341 xmax: 4.143171 ymax: 44.16341
Geodetic CRS: WGS 84
POINT (4.143171 44.16341)