Join and update transect

join_and_update.R

library(dplyr)
library(magrittr)

museum_transects <- read.table("data/museon_linjat.csv", as.is = TRUE, 
                               sep = ";", header = TRUE)

standard_transects <- read.table("data/vakioreitit_lista_suojelualueet.csv", 
                                 as.is = TRUE, sep = ";", header = TRUE)

# Select only columns Reitti and Suojelualue form standard_transects
standard_transects %<>% select(Reitti, Suojelualue)

lsa_transects <- museum_transects %>%
  # Calculate new column `Reitti`
  mutate(Reitti = Nro.2 - 8000) %>% 
  # Join the data frame in process (".") with standard_transect using Reitti
  # as key
  left_join(., standard_transects, by="Reitti") %>%
  # Update the values for LSA (when non-empty) with those from Suojelualue when
  # Suojelualue is non-empty
  mutate(LSA = ifelse(LSA != "", LSA, ifelse(!is.na(Suojelualue), 
                                             Suojelualue, ""))) %>% 
  # Finally, remove columns Reitti and Suojelualue from the data frame in 
  # process to retain the column structure of the original data 
  # (museum_transects)
  select(-Reitti, -Suojelualue)

# Replace "0" with "%" and "1" with "+" in LSA
lsa_transects$LSA[lsa_transects$LSA == "0"] <- "%"
lsa_transects$LSA[lsa_transects$LSA == "1"] <- "+"