New criteria to identify classes, and better legend format

Author: ma-z-am

R/plot_layer_map_layer.R

@@ -244,7 +244,9 @@ plot_layer <- function(
           highestValue <- NULL
         }
       }
-      if(all(foundLevels %in% lowerLimits)){ # already classes -> as factor
+      if(all(foundLevels %in% lowerLimits) & # probably classes -> as factor
+         all(as.integer(lowerLimits) == lowerLimits)
+      ){ 
         LegendText <- foundLevels
         terra::values(r_wgs84)[!is.na(v)] <- factor(v[!is.na(v)])
       } else { # numeric data -> derive classes 
@@ -275,7 +277,6 @@ plot_layer <- function(
         include.lowest = TRUE)
       foundLevels <- c(1,2)
     }
-    
   }
 
   bbox <- matrix(data = terra::ext(r_wgs84),
@@ -311,13 +312,20 @@ plot_layer <- function(
 
   if(plotLegend){
     if(length(foundLevels) > 15){
-      foundLevels <- pretty(foundLevels, n = 15)
+      foundLevels <- pretty(foundLevels, n = 15, shrink.sml = 0.75)
+      foundLevels <- foundLevels[
+        !(foundLevels < 1 | foundLevels > length(LegendText))
+      ]
+      foundLevels[1] <- 1
+      foundLevels[length(foundLevels)] <- length(LegendText)
+      LegendText <- LegendText[foundLevels]
+      classColors <- classColors[foundLevels]
     }
     legend(
       x =  par("usr")[2] + diff(par("usr")[1:2]) / diff(par("plt")[1:2]) * (1 - par("plt")[2]),
       y =  par("usr")[4] + diff(par("usr")[3:4]) / diff(par("plt")[3:4]) * (1 - par("plt")[4]), 
-      legend = LegendText[foundLevels], 
-      fill = classColors[foundLevels], 
+      legend = LegendText, 
+      fill = classColors, 
       bg = rgb(1,1,1, 0.5),
       title = legendTitle, 
       box.col = rgb(1,1,1, 0.5),