diff --git a/genmap.py b/genmap.py
index 8f7d421b1..aaa35690f 100755
--- a/genmap.py
+++ b/genmap.py
@@ -1,17 +1,12 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 
-"
-This is an example script that generates some valid map data.
-"
+# This is an example script that generates some valid map data.
 
 import struct
 import random
-
-def getrand():
-	i = random.randrange(0,2)
-	if i==0:
-		return 0
-	return 254
+import os
+import sys
+from pnoise import pnoise
 
 """
 Map format:
@@ -25,18 +20,72 @@ ffff = -1
 0001 =  1
 """
 
-f = open("map/sectors/00000000/ffff", "wb")
+def to4h(i):
+	s = "";
+	s += '{0:1x}'.format((i>>12) & 0x000f)
+	s += '{0:1x}'.format((i>>8) & 0x000f)
+	s += '{0:1x}'.format((i>>4) & 0x000f)
+	s += '{0:1x}'.format((i>>0) & 0x000f)
+	return s
 
-# version
-f.write(struct.pack('B', 2))
-# is_underground
-f.write(struct.pack('B', 0))
+def getrand():
+	i = random.randrange(0,2)
+	if i==0:
+		return 0
+	return 254
 
-for i in range(0,16*16*16):
-	# Material content
-	f.write(struct.pack('B', getrand()))
-	# Brightness
-	f.write(struct.pack('B', 15))
+def writeblock(mapdir, px,py,pz, version):
+	sectordir = mapdir + "/sectors/" + to4h(px) + to4h(pz)
+	
+	try:
+		os.makedirs(sectordir)
+	except OSError:
+		pass
 
-f.close()
+	f = open(sectordir+"/"+to4h(py), "wb")
 
+	if version == 0:
+		# version
+		f.write(struct.pack('B', 0))
+		# is_underground
+		f.write(struct.pack('B', 0))
+	elif version == 2:
+		# version
+		f.write(struct.pack('B', 2))
+		# is_underground
+		f.write(struct.pack('B', 0))
+	
+	for z in range(0,16):
+		for y in range(0,16):
+			for x in range(0,16):
+				b = 254
+				r = 20.0*pnoise((px*16+x)/100.,(pz*16+z)/100.,0)
+				r += 5.0*pnoise((px*16+x)/25.,(pz*16+z)/25.,0)
+				#print("r="+str(r))
+				y1 = py*16+y
+				if y1 <= r-3:
+					b = 0 #stone
+				elif y1 <= r:
+					b = 1 #grass
+				elif y1 <= 1:
+					b = 9 #water
+				if version == 0:
+					# Material content
+					f.write(struct.pack('B', b))
+				elif version == 2:
+					# Material content
+					f.write(struct.pack('B', b))
+					# Brightness
+					f.write(struct.pack('B', 15))
+
+	f.close()
+
+mapdir = "map"
+
+for z in range(-2,3):
+	for y in range(-1,2):
+		for x in range(-2,3):
+			print("generating block "+str(x)+","+str(y)+","+str(z))
+			writeblock(mapdir, x,y,z, 0)
+
+#END
diff --git a/pnoise.py b/pnoise.py
new file mode 100644
index 000000000..fcab5ac15
--- /dev/null
+++ b/pnoise.py
@@ -0,0 +1,102 @@
+#
+# A python perlin noise implementation, from
+# http://www.fundza.com/c4serious/noise/perlin/perlin.html
+#
+# This is used for testing how to create maps with a python script.
+#
+
+import math
+p = (
+151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,
+30,69,142,8,99,37,240,21,10,23,190,6,148,247,120,234,75,0,26,197,
+62,94,252,219,203,117,35,11,32,57,177,33,88,237,149,56,87,174,20,
+125,136,171,168,68,175,74,165,71,134,139,48,27,166,77,146,158,231,
+83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,102,
+143,54,65,25,63,161,1,216,80,73,209,76,132,187,208,89,18,169,200,
+196,135,130,116,188,159,86,164,100,109,198,173,186,3,64,52,217,226,
+250,124,123,5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,
+58,17,182,189,28,42,223,183,170,213,119,248,152,2,44,154,163,70,
+221,153,101,155,167,43,172,9,129,22,39,253,19,98,108,110,79,113,
+224,232,178,185,112,104,218,246,97,228,251,34,242,193,238,210,144,
+12,191,179,162,241,81,51,145,235,249,14,239,107,49,192,214,31,181,
+199,106,157,184,84,204,176,115,121,50,45,127,4,150,254,138,236,
+205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
+151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,
+30,69,142,8,99,37,240,21,10,23,190,6,148,247,120,234,75,0,26,197,
+62,94,252,219,203,117,35,11,32,57,177,33,88,237,149,56,87,174,20,
+125,136,171,168,68,175,74,165,71,134,139,48,27,166,77,146,158,231,
+83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,102,
+143,54,65,25,63,161,1,216,80,73,209,76,132,187,208,89,18,169,200,
+196,135,130,116,188,159,86,164,100,109,198,173,186,3,64,52,217,226,
+250,124,123,5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,
+58,17,182,189,28,42,223,183,170,213,119,248,152,2,44,154,163,70,
+221,153,101,155,167,43,172,9,129,22,39,253,19,98,108,110,79,113,
+224,232,178,185,112,104,218,246,97,228,251,34,242,193,238,210,144,
+12,191,179,162,241,81,51,145,235,249,14,239,107,49,192,214,31,181,
+199,106,157,184,84,204,176,115,121,50,45,127,4,150,254,138,236,
+205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180)
+  
+def lerp(t, a, b):
+    return a + t * (b - a)
+  
+def fade(t):
+    return t * t * t * (t * (t * 6 - 15) + 10)
+  
+def grad(hash, x, y, z):
+    h = hash & 15
+    if h < 8:
+        u = x
+    else:
+        u = y
+    if h < 4:
+        v = y
+    elif h == 12 or h == 14:
+        v = x
+    else:
+        v = z
+    if h & 1 != 0:
+        u = -u
+    if h & 2 != 0:
+        v = -v
+    return u + v
+  
+def pnoise(x, y, z):
+    global p
+    X = int(math.floor(x)) & 255
+    Y = int(math.floor(y)) & 255
+    Z = int(math.floor(z)) & 255
+    x -= math.floor(x)
+    y -= math.floor(y)
+    z -= math.floor(z)
+    
+    u = fade(x)
+    v = fade(y)
+    w = fade(z)
+    
+    A =  p[X] + Y
+    AA = p[A] + Z
+    AB = p[A + 1] + Z
+    B =  p[X + 1] + Y
+    BA = p[B] + Z
+    BB = p[B + 1] + Z
+    
+    pAA = p[AA]
+    pAB = p[AB]
+    pBA = p[BA]
+    pBB = p[BB]
+    pAA1 = p[AA + 1]
+    pBA1 = p[BA + 1]
+    pAB1 = p[AB + 1]
+    pBB1 = p[BB + 1]
+    
+    gradAA =  grad(pAA, x,   y,   z)
+    gradBA =  grad(pBA, x-1, y,   z)
+    gradAB =  grad(pAB, x,   y-1, z)
+    gradBB =  grad(pBB, x-1, y-1, z)
+    gradAA1 = grad(pAA1,x,   y,   z-1)
+    gradBA1 = grad(pBA1,x-1, y,   z-1)
+    gradAB1 = grad(pAB1,x,   y-1, z-1)
+    gradBB1 = grad(pBB1,x-1, y-1, z-1)
+    return lerp(w, 
+    lerp(v, lerp(u, gradAA, gradBA), lerp(u, gradAB, gradBB)),
+    lerp(v, lerp(u, gradAA1,gradBA1),lerp(u, gradAB1,gradBB1)))    
diff --git a/src/map.cpp b/src/map.cpp
index 82317aec5..2a92f6733 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -4711,6 +4711,9 @@ plan_b:
 	/*
 		Plan B: Get from map generator perlin noise function
 	*/
+	// This won't work if proper generation is disabled
+	if(m_chunksize == 0)
+		return WATER_LEVEL+2;
 	double level = base_rock_level_2d(m_seed, p2d);
 	return (s16)level;
 }
diff --git a/src/serialization.h b/src/serialization.h
index 26ab90e36..c87162e69 100644
--- a/src/serialization.h
+++ b/src/serialization.h
@@ -29,7 +29,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	NOTE: The goal is to increment this so that saved maps will be
 	      loadable by any version. Other compatibility is not
 		  maintained.
-	Serialization format versions:
+	Serialization format versions (for raw map data (blocks, nodes, sectors)):
 	== Unsupported ==
 	0: original networked test with 1-byte nodes
 	1: update with 2-byte nodes