add ability to find highest level

R/afriadmin.r

@@ -1,35 +1,67 @@
 
 
 
-#todo function to find the highest level for a country
+
 
 #todo add country outlines for whole continent as single file
 #todo mayne if I saved all outlines as a single file it would be easier to subset etc.
 
 #todo allow countrynames as well as iso3
-#tood add error checking for countries
+#todo add error checking for countries
 #todo vectorise iso3 to allow combining countries
 #todo maybe vectorise level too
 
+#todo is it good idea to name function same as package ?
 afriadmin <- function(iso3 = 'AGO',
- level = 2,
+ level = 'max',
  plot = TRUE) {
 
  #GADM_SF_URL = "https://biogeo.ucdavis.edu/data/gadm3.6/Rsf/gadm36_"
+ #initially store files directly as downloaded from gadm
+
+ path <- system.file(package="afriadmin","/external")
 
  #to allow iso3 in lower case
  iso3 <- toupper(iso3)
 
+ maxlevel <- maxadmin()
+
+ if (level=='max')
+ {
+ level <- maxlevel
+ message("returning max admin level available for ",iso3,", ",maxlevel)
+ }
+ else if (level > maxlevel)
+ {
+ warning("max admin level available for ",iso3," is ",maxlevel," you requested ",level)
+ #maybe do this to return mot detailed available
+ level <- maxlevel
+ }
+
+
  filename <- paste0(iso3,'_adm',level,'.sf.rds')
 
- path <- system.file(package="afriadmin")
+ # path <- system.file(package="afriadmin")
+ # sf1 <- readRDS(file.path(path, "external/", filename))
 
- sf1 <- readRDS(file.path(path, "external/", filename))
+ sf1 <- readRDS(file.path(path, filename))
 
  if (plot) plot(sf::st_geometry(sf1))
 
  return(sf1)
-
 }
 
 
+# return max admin level for a country
+# initialy gadm but could be other sources too
+# todo should be vectorised
+maxadmin <- function(iso3 = 'AGO') {
+
+ path <- system.file(package="afriadmin","/external")
+
+ allfiles <- list.files(path)
+ countryfiles <- allfiles[ substr(allfiles,1,3)==iso3 ]
+ levs <- as.numeric( substr(countryfiles,8,8) )
+ lev_hi <- max(levs)
+ lev_hi
+}