leaflet02.r

# for each file obtain the EXIF codes and extract the coordinates
GPStags <- apply(array(file_info$file.name), 1, function(x) {
  EXIF_code <- NULL
  try (EXIF_code <- attr(GDALinfo(x), "mdata"), silent = T)
  if (is.null(EXIF_code)) return(data.frame(lon = NA, lat = NA, dateTime = NA)) else return(get_EXIF_coordinate(EXIF_code))
})
#bind the results:
GPStags <- do.call(rbind, GPStags)

# store in the data.frame
file_info <- cbind(file.name = file_info$file.name , GPStags)

# select only rows that hold location data:
file_sub <- subset(file_info, !is.na(lon))

# clean up after us
rm(GPStags)

# hours past midnight (2+ is for converting UTC to CET):
file_sub$hours <- 2 + (as.numeric(file_sub$dateTime) %% (60*60*24))/(60*60)

# creat palette for the hours after midnight:
pal <- colorNumeric("Spectral", file_sub$hours)