add checking that the data exist

NAMESPACE

@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+export(check_data_exist)
 export(check_rnaturalearthdata)
 export(check_rnaturalearthhires)
 export(install_rnaturalearthdata)

R/check_data_exist.r

@@ -0,0 +1,63 @@
+#' check whether the requested data exist on Natural Earth
+#'
+#' checks from a list dependent on type, category and scale. If it returns FALSE the data may still exist on the website.
+#' Doesn't yet do checking on raster names because I found the naming convention too tricky.
+#' 
+#' @param scale scale of map to return, one of \code{110}, \code{50}, \code{10} or \code{'small'}, \code{'medium'}, \code{'large'}
+#' @param type type of natural earth file to download one of 'countries', 'map_units', 'map_subunits', 'sovereignty', 'states'
+#'    OR the portion of any natural earth vector url after the scale and before the . 
+#'    e.g. for 'ne_50m_urban_areas.zip' this would be 'urban_areas'
+#' @param category one of natural earth categories : 'cultural', 'physical', 'raster'
+
+#' @examples
+#' check_data_exist( scale = 110, category = 'cultural', type = 'countries' )
+#' # type not in list for this category
+#' check_data_exist( scale = 110, category = 'physical', type = 'airports' )
+#' # type in list but scale shows FALSE
+#' check_data_exist( scale = 110, category = 'cultural', type = 'airports' )
+#' 
+#' @return TRUE or FALSE
+#' @export
+
+check_data_exist <- function(scale = 110,
+                         type,
+                         category = c('cultural', 'physical', 'raster')
+) 
+{
+
+  # check permitted category
+  category <- match.arg(category) 
+
+  # todo doesn't yet check raster
+  # I would need to create a data_list_raster.csv file
+  if (category=='raster') return(TRUE)
+
+  # check on permitted scales, convert names to numeric
+  scale <- check_scale(scale)
+
+
+  df_data <- read.csv( system.file("extdata", paste0("data_list_", category, ".csv"), package = "rnaturalearth") )
+
+
+  #first check if type is within the list
+  if ( ! type %in% df_data$type )
+  {
+    warning(type," seems not to be in the list for category=", category, " maybe try the other category of c('cultural', 'physical')") 
+    return(FALSE)
+  }
+
+  #df_data[df_data$type=='roads', 'scale110']  
+
+  exist <- df_data[df_data$type==type,paste0("scale",scale)]  
+
+
+  if (!exist)
+  {
+    warning("your combination of type, category, scale",
+            " seem not to exist in the list of Natural Earth data so you may get a download fail message.",
+            " Check ?ne_download or http://www.naturalearthdata.com/features/ to see data availability.")
+  }
+
+  return(exist)
+
+}

R/ne_download.r

@@ -32,8 +32,8 @@
 #'   reefs              	       \tab -	        \tab -      	\tab y        \cr 
 #'   category = 'cultural', type = '[below]'             \cr    
 #'   populated_places        	   \tab y	        \tab y      	\tab y        \cr
-#'   admin_0_boundary_lines_land \tab y	        \tab y      	\tab y        \cr
-#'   admin_0_breakaway_disputed_areas \tab -	        \tab y      	\tab y        \cr
+#'   boundary_lines_land \tab y	        \tab y      	\tab y        \cr
+#'   breakaway_disputed_areas \tab -	        \tab y      	\tab y        \cr
 #'   airports              	     \tab -	        \tab y      	\tab y        \cr
 #'   ports              	       \tab -	        \tab y      	\tab y        \cr
 #'   urban_areas              	 \tab -	        \tab y      	\tab y        \cr

R/ne_file_name.r

@@ -27,16 +27,26 @@ ne_file_name <- function(scale = 110,
   scale <- check_scale(scale)
 
   # check permitted category
-  category <- match.arg(category)  
-  # type is left unchecked so users can specify any natearth filename
+  category <- match.arg(category) 
 
-  # some combinations are not available
-  if ( type=='map_subunits' & scale==110 )
-    stop("The combination of type=",type,"and scale=",scale,"is not available in Natural Earth")
+  # check type against lists in package to warn user if they try something
+  # that seems not to exist
+  # however continue to try the download to give user flexibility
+  # to get something I may have missed out of my list or has been added more recently
+  check_data_exist( scale = scale, category = category, type = type )
 
+
   # add admin_0 to known types
-  if (type=='countries' | type=='map_units' | type=='map_subunits' | type=='sovereignty' | type=='tiny_countries' ) 
-    type <- paste0('admin_0_',type)
+  if ( type %in% c('countries', 'map_units', 'map_subunits', 'sovereignty', 'tiny_countries',
+                   'boundary_lines_land', 
+                   'pacific_groupings', 
+                   'breakaway_disputed_areas',
+                   'boundary_lines_disputed_areas',
+                   'boundary_lines_maritime_indicator') )
+  {
+    type <- paste0('admin_0_',type)    
+  }
+
 
   # add admin_1 to known types
   # this actually just expands 'states' to the name including lakes

inst/extdata/data_list_cultural.csv

@@ -0,0 +1,18 @@
+type,scale110, scale50,scale10
+countries,TRUE,TRUE,TRUE
+map_units,TRUE,TRUE,TRUE
+map_subunits,FALSE,TRUE,TRUE
+sovereignty,TRUE,TRUE,TRUE
+tiny_countries,TRUE,TRUE,TRUE
+states,FALSE,TRUE,TRUE
+populated_places,TRUE,TRUE,TRUE
+boundary_lines_land,TRUE,TRUE,TRUE
+pacific_groupings,TRUE,TRUE,TRUE
+breakaway_disputed_areas,FALSE,TRUE,TRUE
+boundary_lines_disputed_areas,FALSE,TRUE,TRUE
+boundary_lines_maritime_indicator,FALSE,TRUE,TRUE
+airports,FALSE,TRUE,TRUE
+ports,FALSE,TRUE,TRUE
+urban_areas,FALSE,TRUE,TRUE
+roads,FALSE,FALSE,TRUE
+railroads,FALSE,FALSE,TRUE

inst/extdata/data_list_physical.csv

@@ -0,0 +1,19 @@
+type,scale110, scale50,scale10
+coastline,TRUE,TRUE,TRUE
+land,TRUE,TRUE,TRUE
+ocean,TRUE,TRUE,TRUE
+rivers_lake_centerlines,TRUE,TRUE,TRUE
+lakes,TRUE,TRUE,TRUE
+glaciated_areas,TRUE,TRUE,TRUE
+antarctic_ice_shelves_polys,TRUE,TRUE,TRUE
+geographic_lines,TRUE,TRUE,TRUE
+graticules_1,TRUE,TRUE,TRUE
+graticules_5,TRUE,TRUE,TRUE
+graticules_10,TRUE,TRUE,TRUE
+graticules_15,TRUE,TRUE,TRUE
+graticules_20,TRUE,TRUE,TRUE
+graticules_30,TRUE,TRUE,TRUE
+wgs84_bounding_box,TRUE,TRUE,TRUE
+playas,FALSE,TRUE,TRUE
+minor_islands,FALSE,FALSE,TRUE
+reefs,FALSE,FALSE,TRUE