Convert Geo Coordinates from Degree-Decimal-Minutes to Decimal-Degrees

deg-dec-min-to-dec-deg.R

## Example function for converting geo coordinates from degree-decimal minutes to decimal degrees.
## For full discussion please see StackOverflow #14404596 
## https://stackoverflow.com/questions/14404596/converting-geo-coordinates-from-degree-to-decimal

library(tidyr)
library(dplyr)

df <- tribble(         
~site,  ~lat,   ~lon,
"105252", "30°25.264", "9°01.331",
"105253", "30°39.237", "8°10.811",
"105255", "31°37.760", "8°06.040",
"105258", "31°41.190", "8°06.557",
"105259", "31°41.229", "8°06.622",
"105260", "31°38.891", "8°06.281",)

# unicode for degree symbol
# deg <- "\u00b0"

deg_decmin_to_decdeg <- function(df) {
    x <- df %>% 
        separate(lat, paste("lat",c("d","m"), sep= "_"), sep="\u00b0") %>% 
        separate(lon, paste("lon",c("d","m"), sep= "_"), sep="\u00b0") %>% 
        mutate(lat_d = as.numeric(lat_d),
               lat_m = as.numeric(lat_m),
               lon_d = as.numeric(lon_d),
               lon_m = as.numeric(lon_m)) %>% 
        transmute(site = site,
                  lat_dec = lat_d + lat_m/60,
                  lon_dec = lon_d + lon_m/60)
  return(x)
}


cord2 <- deg_decmin_to_decdeg(df)