# Degree-minute-second to decimal coordinates

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The ‘dms2dec’ function, posted here a while ago to convert longitude-latitude coordinates from degree-minute-second to decimal format, has recently been updated to accomodate more cases that I and my course participants run into. The function is pasted below and is also available on GitHub, from where it can be sourced directly from R with `source("https://raw.githubusercontent.com/AMBarbosa/unpackaged/master/dms2dec", encoding = "UTF-8")`

. Feedback welcome on whether it is working properly!

dms2dec <- function(dms, separators = c("º", "°", "\'", "’", "’’", "\"", "\'\'", "\\?")) { # version 1.4 (2 Feb 2022) # dms: a vector of latitude or longitude in degrees-minutes-seconds-hemisfere, e.g. 41° 34' 10.956" N (with or without spaces) # separators: the characters that are separating degrees, minutes and seconds in 'dms'; mind these are taken in the order in which they appear and not interpreted individually, i.e. 7'3º will be taken as 7 degrees, 3 minutes! input data are assumed to be properly formatted dms <- as.character(dms) dms <- gsub(pattern = " ", replacement = "", x = dms) for (s in separators) dms <- gsub(pattern = s, replacement = "_splitHere_", x = dms) splits <- strsplit(dms, split = "_splitHere_") n <- length(dms) deg <- min <- sec <- hem <- vector("character", n) for (i in 1:n) { deg[i] <- splits[[i]][1] min[i] <- splits[[i]][2] if (length(splits[[i]]) < 4) { hem[i] <- splits[[i]][3] } else { sec[i] <- splits[[i]][3] hem[i] <- splits[[i]][4] } } dec <- colSums(rbind(as.numeric(deg), (as.numeric(min) / 60), (as.numeric(sec) / 3600)), na.rm = TRUE) sign <- ifelse (hem %in% c("N", "E"), 1, -1) hem_miss <- which(is.na(hem)) if (length(hem_miss) > 0) { warning("Hemisphere not specified at position(s) ", hem_miss, ", so the sign of the resulting coordinates may be wrong.") } dec <- sign * dec return(dec) } # end dms2dec function

Usage example:

mydata$lat_dd <- dms2dec(mydata$lat_dms) mydata$lon_dd <- dms2dec(mydata$lon_dms)

To

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