UTM Zone conversion

[ateucher]

This adds a function utm_convert() to convert tabular data in UTM zones to a standard CRS (default BC Albers). This is especially useful for field studies with data collected over a wide area that spans UTM zones.

The location data is expected to be in two columns with x and y, and the zone can be either in a column (when the data set spans multiple UTM zones), or can be specified for the whole data set. E.g.:

# Data with multiple zones, and a column denoting the zone
df <- data.frame(
 animalid = c("a", "b", "c"),
 zone = c(10, 11, 11),
 easting = c(500000, 800000, 700000),
 northing = c(5000000, 3000000, 1000000)
)

utm_convert(df, xcol = "easting", ycol = "northing", zone = "zone")
#> Simple feature collection with 3 features and 6 fields
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: 1237767 ymin: -3576605 xmax: 2418043 ymax: 21953.96
#> Projected CRS: NAD83 / BC Albers
#>      animalid zone       X           Y easting northing
#> 10          a   10 1237767    21953.96   5e+05    5e+06
#> 11.2        b   11 2275642 -1807950.91   8e+05    3e+06
#> 11.3        c   11 2418043 -3576604.70   7e+05    1e+06
#>                      geometry
#> 10   POINT (1237767 21953.96)
#> 11.2 POINT (2275642 -1807951)
#> 11.3 POINT (2418043 -3576605)

# Data all in one zone, specify a single zone:
df <- data.frame(
 animalid = c("a", "b"),
 easting = c(500000, 800000),
 northing = c(5000000, 3000000)
)

utm_convert(df, xcol = "easting", ycol = "northing", zone = 11)
#> Simple feature collection with 2 features and 5 fields
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: 1711595 ymin: -1807951 xmax: 2275642 ymax: 62209.93
#> Projected CRS: NAD83 / BC Albers
#>   animalid       X           Y easting northing                 geometry
#> 1        a 1711595    62209.93   5e+05    5e+06 POINT (1711595 62209.93)
#> 2        b 2275642 -1807950.91   8e+05    3e+06 POINT (2275642 -1807951)

^{Created on 2023-11-17 with reprex v2.0.2}