diff --git a/src/main.lua b/src/main.lua
index 911a108..e46a97c 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -4,35 +4,49 @@ local lume = require "lib.lume"
 
 local map = {}
 
+local biomes = {
+  water = {
+    altitude = {min = 0, max = 0.2},
+    color = {0, 0, 1, 1},
+  },
+  sand = {
+    altitude = {min = 0.2, max = 0.215},
+    color = {1, 1, 0, 1},
+  },
+  grass = {
+    altitude = {min = 0.215, max = 0.34},
+    color = {0, 1, 0, 1},
+  },
+  trees = {
+    altitude = {min = 0.34, max = 0.72},
+    color = {0, 0.67, 0, 1},
+  },
+  stone = {
+    altitude = {min = 0.72, max = 0.9},
+    color = {0.67, 0.67, 0.67, 1},
+  },
+  ice = {
+    altitude = {min = 0.9, max = 1},
+    color = {1, 1, 1, 1}
+  },
+}
+
 love.load = function()
   map.size = 150
-  map.height = heightmap.create(map.size, map.size, 0, 1)
+  map.altitude = heightmap.create(map.size, map.size, 0, 1)
   map.temperature = heightmap.create(map.size, map.size, 0, 1)
   map.humidity = heightmap.create(map.size, map.size, 0, 1)
 
-  -- weird mixing idea test
-  -- why does this average things out?
-  -- trying to renormalize it now..
-  local temporary_maps = {}
-  for i = 1, 3 do
-    temporary_maps[i] = heightmap.create(map.size, map.size, 0, 1)
-  end
-  for x = 0, map.height.w do
-    for y = 0, map.height.h do
-      map.height[x][y] = (map.height[x][y] + temporary_maps[1][x][y] + temporary_maps[2][x][y] + temporary_maps[3][x][y] ) / 4
-    end
-  end
-  heightmap.normalize(map.height, 0, 1)
-
   -- if true then return end
 
   -- lower temperature by half height
   -- NOTE ruins "normalization" but that's fine once we have "real" numbers to work with
   for x = 0, map.temperature.w do
     for y = 0, map.temperature.h do
-      map.temperature[x][y] = math.max(0, map.temperature[x][y] - map.height[x][y] / 2)
+      map.temperature[x][y] = math.max(0, map.temperature[x][y] - map.altitude[x][y] / 2)
     end
   end
+  heightmap.normalize(map.temperature, 0, 1)
 
   -- modify temperature by latitude
   -- TODO would be more efficient to calculate Y in outer loop, since X does not change the distance
@@ -44,6 +58,7 @@ love.load = function()
       map.temperature[x][y] = lume.clamp(map.temperature[x][y] - distance / map.size / 2, 0, 1)
     end
   end
+  heightmap.normalize(map.temperature, 0, 1)
 
   -- increase humidity by half temperature
   for x = 0, map.humidity.w do
@@ -53,11 +68,21 @@ love.load = function()
   end
 
   -- planetizer!
+  map.terrain = {}
   local radius = (map.size / 2)^2
-  for x = 0, map.height.w do
-    for y = 0, map.height.h do
-      if lume.distance(x, y, map.size / 2, map.size / 2, true) > radius then
-        map.height[x][y] = nil
+  for x = 0, map.size do
+    map.terrain[x] = {}
+    for y = 0, map.size do
+      if lume.distance(x, y, map.size / 2, map.size / 2, true) < radius then
+        for name, biome in pairs(biomes) do
+          local value = map.altitude[x][y]
+          -- this allows a non-deterministic change of terrain
+          --  depending on which biome is checked first but I don't care right now]
+          if value >= biome.altitude.min and value <= biome.altitude.max then
+            map.terrain[x][y] = biome.color
+            break
+          end
+        end
       end
     end
   end
@@ -70,31 +95,14 @@ end
 love.draw = function()
   local tile_size = 2
 
-  for x = 0, map.height.w do
-    for y = 0, map.height.h do
+  for x = 0, map.altitude.w do
+    for y = 0, map.altitude.h do
       -- raw heightmap
-      -- NOTE will break with planetizer enabled!
-      -- local value = map.height[x][y]
-      -- love.graphics.setColor(value, value, value, 1)
-      -- love.graphics.rectangle("fill", x * tile_size, y * tile_size, tile_size, tile_size)
-
-      -- even weighting between height and temperature
-      -- local value = map.height[x][y] / 2 + map.temperature[x][y] / 2
-      -- if value < 0.2 then
-      --   love.graphics.setColor(0, 0, 1, 1)
-      -- elseif value < 0.215 then
-      --   love.graphics.setColor(1, 1, 0, 1)
-      -- elseif value < 0.34 then
-      --   love.graphics.setColor(0, 1, 0, 1)
-      -- elseif value < 0.72 then
-      --   love.graphics.setColor(0, 0.67, 0, 1)
-      -- elseif value < 0.9 then
-      --   love.graphics.setColor(0.67, 0.67, 0.67, 1)
-      -- else
-      --   -- love.graphics.setColor(0, 0, 0, 1) -- temporary nothing
-      --   love.graphics.setColor(1, 1, 1, 1)
-      -- end
-      -- love.graphics.rectangle("fill", x * tile_size, y * tile_size, tile_size, tile_size)
+      local value = map.altitude[x][y]
+      if value then
+        love.graphics.setColor(value, value, value, 1)
+        love.graphics.rectangle("fill", x * tile_size, y * tile_size, tile_size, tile_size)
+      end
 
       -- temperature map
       local value = map.temperature[x][y]
@@ -107,22 +115,9 @@ love.draw = function()
       love.graphics.rectangle("fill", x * tile_size, map.size * tile_size + y * tile_size, tile_size, tile_size)
 
       -- "naive" biomed map
-      local value = map.height[x][y]
+      local value = map.terrain[x][y]
       if value then
-        if value < 0.2 then
-          love.graphics.setColor(0, 0, 1, 1)
-        elseif value < 0.215 then
-          love.graphics.setColor(1, 1, 0, 1)
-        elseif value < 0.34 then
-          love.graphics.setColor(0, 1, 0, 1)
-        elseif value < 0.72 then
-          love.graphics.setColor(0, 0.67, 0, 1)
-        elseif value < 0.9 then
-          love.graphics.setColor(0.67, 0.67, 0.67, 1)
-        else
-          -- love.graphics.setColor(0, 0, 0, 1) -- temporary nothing
-          love.graphics.setColor(1, 1, 1, 1)
-        end
+        love.graphics.setColor(value)
         love.graphics.rectangle("fill", map.size * tile_size + x * tile_size, map.size * tile_size + y * tile_size, tile_size, tile_size)
       end
     end