[Freeciv-Dev] (PR#9627) PATCH: correct some parameters in map generator and clean-up

["Marcelo Burda" <mburda@xxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9627 >

Patch update
LAST CHANGES, some part ot these patch are done as spearate patch to be
apply befor it

Marcelo

diff -ruN -Xfreeciv/diff_ignore freeciv_/common/map.h freeciv__/common/map.h
--- freeciv_/common/map.h       2004-08-27 20:20:38.925459376 +0200
+++ freeciv__/common/map.h      2004-08-27 20:08:57.970020800 +0200
@@ -629,7 +629,7 @@
 #define MAP_MIN_SEED             0
 #define MAP_MAX_SEED             (MAX_UINT32 >> 1)
 
-#define MAP_DEFAULT_LANDMASS     30
+#define MAP_DEFAULT_LANDMASS     35
 #define MAP_MIN_LANDMASS         15
 #define MAP_MAX_LANDMASS         85
 
@@ -637,11 +637,11 @@
 #define MAP_MIN_RICHES           0
 #define MAP_MAX_RICHES           1000
 
-#define MAP_DEFAULT_MOUNTAINS    30
-#define MAP_MIN_MOUNTAINS        10
+#define MAP_DEFAULT_MOUNTAINS    10
+#define MAP_MIN_MOUNTAINS        5
 #define MAP_MAX_MOUNTAINS        100
 
-#define MAP_DEFAULT_GRASS       35
+#define MAP_DEFAULT_GRASS       55
 #define MAP_MIN_GRASS           20
 #define MAP_MAX_GRASS           100
 
@@ -657,7 +657,7 @@
 #define MAP_MIN_RIVERS           0
 #define MAP_MAX_RIVERS           100
 
-#define MAP_DEFAULT_FORESTS      20
+#define MAP_DEFAULT_FORESTS      12
 #define MAP_MIN_FORESTS          0
 #define MAP_MAX_FORESTS          100
 
diff -ruN -Xfreeciv/diff_ignore freeciv_/server/mapgen.c 
freeciv__/server/mapgen.c
--- freeciv_/server/mapgen.c    2004-08-27 20:29:42.144877472 +0200
+++ freeciv__/server/mapgen.c   2004-08-27 21:33:56.303956232 +0200
@@ -76,9 +76,13 @@
 static int *river_map;
 
 static int *height_map;
-static const int maxval = 1000;
-static int seaval=0, mountainsval =0;
-static int forests=0;
+static const int maxval=1000;
+static int reliefval=0, seaval=0;
+static int forests_to_be_placed =0;
+static int deserts_to_be_placed=0;
+static int grass_to_be_placed=0;
+static int plains_to_be_placed=0;
+static int swamps_to_be_placed=0;
 
 struct isledata {
   int goodies;
@@ -99,13 +103,27 @@
 /* An estimate of the linear (1-dimensional) size of the map. */
 #define SQSIZE MAX(1, sqrt(map.xsize * map.ysize / 1000))
 
+/* define the 5 region of a Earth like map
+   =========================================================
+    0-COLD_LV                cold region: 
+    COLD_LV-TREOPICAL_LV     temperate wet region: 
+    TROPICAL_LV-MAX_TEMP     tropical wet region:
+
+   and a dry region, this last one can ovelap others 
+   DRY_MIN_LEVEL- DRY_MAX_LEVEL
+ */
+#define COLD_LEVEL (10 * MAX_TEMP / 100)
+#define TROPICAL_LEVEL (70 * MAX_TEMP / 100)
+#define DRY_MIN_LEVEL (65 * MAX_TEMP / 100)
+#define DRY_MAX_LEVEL (80 * MAX_TEMP / 100)
+
 /* used to create the poles and for separating them.  In a
  * mercator projection map we don't want the poles to be too big. */
 #define ICE_BASE_LEVEL                                         \
   ((!topo_has_flag(TF_WRAPX) || !topo_has_flag(TF_WRAPY))      \
    /* 5% for little maps; 2% for big ones */                   \
    ? MAX_TEMP * (3 + 2 * SQSIZE) / (100 * SQSIZE)              \
-   : 5 * MAX_TEMP / 100  /* 5% for all maps */)
+   : COLD_LEVEL / 2  /* for all maps */)
 
 /********************************************************************
  * used to initialize a array with some value
@@ -300,24 +318,57 @@
 }
 
 /**************************************************************************
-  make_mountains() will convert all squares that are higher than thill to
+  we don't want huge areas of grass/plains, 
+  so we put in a hill here and there, where it gets too 'clean' 
+
+  Return TRUE if the terrain at the given map position is "clean".  This
+  means that all the terrain for 2 squares around it is not mountain or hill.
+****************************************************************************/
+static bool terrain_is_clean(int map_x, int map_y,int thill, int my_high)
+{
+  int biger_me = 0;
+  square_iterate(map_x, map_y, 2, x1, y1) {
+    if (hmap(x1, y1) > thill) {
+      return FALSE;
+    }
+    if (hmap(x1, y1) > my_high){
+      if(map_distance(map_x, map_y, x1, y1) == 1) {
+       return FALSE;
+      }
+      if(++biger_me > 2) {
+       return FALSE;
+      };
+    }
+  } square_iterate_end;
+
+  if ((thill - seaval) * (biger_me)  > (my_high - seaval) * 4 ) {
+      return FALSE;
+  }
+  return TRUE;
+}
+
+/**************************************************************************
+  make_relief() will convert all squares that are higher than thill to
   mountains and hills. Notice that thill will be adjusted according to
   the map.mountains value, so increase map.mountains and you'll get more 
   hills and mountains (and vice versa).
+  TODO: extend to place ocean/deepocean/abys relief in oceans
 **************************************************************************/
-static void make_mountains(void)
+static void make_relief()
 {
-  mountainsval = ((maxval - seaval)* (100 - map.mountains)) / 100 + seaval;
+  reliefval = ((maxval - seaval)* (100 - map.mountains)) / 100 + seaval;
   whole_map_iterate(x, y) {
-    if (hmap(x, y) > mountainsval && !is_ocean(map_get_terrain(x,y))) { 
+    if (not_placed(x,y) 
+       && (hmap(x, y) > reliefval 
+           || terrain_is_clean(x, y, reliefval, hmap(x, y)))) { 
       /* Randomly place hills and mountains on "high" tiles.  But don't
        * put hills near the poles (they're too green). */
-      if (myrand(100) > 75 
-         || map_temperature(x, y) <= MAX_TEMP / 10) {
+      if (myrand(100) > 70 
+         || map_temperature(x, y) <= COLD_LEVEL) {
        map_set_terrain(x, y, T_MOUNTAINS);
-      } else if (myrand(100) > 25) {
+      } else {
        map_set_terrain(x, y, T_HILLS);
-      }
+      }  
     }
   } whole_map_iterate_end;
 }
@@ -355,6 +406,24 @@
     }
   } whole_map_iterate_end;
 }
+/*************************************************************************
+ if separatepoles is set, return false if this tile has to kip ocean
+************************************************************************/
+static bool ok_for_separate_poles(int x, int y) 
+{
+  if (!map.separatepoles) {
+    return TRUE;
+  }
+  adjc_iterate(x, y, x1, y1) {
+    if(!is_ocean(map_get_terrain(x1, y1))
+       && map_get_continent(x1, y1 ) != 0) {
+      return FALSE;
+    }
+  } adjc_iterate_end;
+  return TRUE;
+}
+
+
 
 /****************************************************************************
   Place untextured land at the poles.  This is used by generators 1 and 5.
@@ -365,30 +434,17 @@
   struct tile *ptile;
   int T;
 
+  assign_continent_numbers();
   whole_map_iterate(map_x, map_y) {
     T = map_temperature(map_x, map_y); /* temperature parameter */
     ptile = map_get_tile(map_x, map_y);
-    if (T < 1.5 * ICE_BASE_LEVEL) {
+    if (T < 1.5 * ICE_BASE_LEVEL && ok_for_separate_poles(map_x, map_y)) {
       ptile->terrain = T_NOT_PLACED;
-    } else if ((T <= 2 * ICE_BASE_LEVEL) && myrand(10) > 4 ) { 
+      map_set_continent(map_x, map_y, 0);
+    } else if ((T <= 2 * ICE_BASE_LEVEL) 
+              && myrand(10) > 4 && ok_for_separate_poles(map_x, map_y)) { 
       ptile->terrain = T_NOT_PLACED;
-    }
-  } whole_map_iterate_end;
-}
-
-/****************************************************************************
-  Create tundra in cold zones.  Used by generators 1 and 5.  This must be
-  called after make_arctic since it will fill all remaining untextured
-  areas (we don't want any grassland left on the poles).
-****************************************************************************/
-static void make_tundra(void)
-{
-  whole_map_iterate(x, y) {
-    int T = map_temperature(x, y);
-
-    if (not_placed(x,y) 
-       && (2 * ICE_BASE_LEVEL > T || myrand(MAX_TEMP/5) > T)) {
-      map_set_terrain(x, y, T_TUNDRA);
+      map_set_continent(map_x, map_y, 0);
     }
   } whole_map_iterate_end;
 }
@@ -401,8 +457,8 @@
   whole_map_iterate(x, y) {
     int T = map_temperature(x, y);
 
-    if (not_placed(x,y) 
-       && myrand(15 * MAX_TEMP / 100) > T -  ICE_BASE_LEVEL 
+    if (not_placed(x, y)
+       && myrand(1.5 * COLD_LEVEL) > T -  ICE_BASE_LEVEL 
        && T <= 3 * ICE_BASE_LEVEL) {
       map_set_terrain(x, y, T_ARCTIC);
     }
@@ -423,14 +479,16 @@
 {
   const int DeltaT = MAX_TEMP / (3 * SQSIZE);
 
+  if(deserts_to_be_placed <= 0) { return; }
+
   if (abs(hmap(x, y) - height) < diff 
-      && not_placed(x,y)) {
+      && not_placed(x, y) && count_ocean_near_tile(x,y) <= 2) {
     map_set_terrain(x, y, T_DESERT);
+    deserts_to_be_placed--;
     cardinal_adjc_iterate(x, y, x1, y1) {
       make_desert(x1, y1, height,
                  diff - 1 - abs(map_temperature(x1, y1) - base_T) / DeltaT,
                  base_T);
-     
     } cardinal_adjc_iterate_end;
   }
 }
@@ -443,125 +501,174 @@
 **************************************************************************/
 static void make_forest(int map_x, int map_y, int height, int diff)
 {
-  int nat_x, nat_y, T;
+  int T;
 
-  map_to_native_pos(&nat_x, &nat_y, map_x, map_y);
-  T = map_temperature(map_x, map_y);
+  if(forests_to_be_placed <= 0) { return; }
   if (not_placed(map_x, map_y)) {
-    if (T > 8 * MAX_TEMP / 10 
-       && myrand(1000) > 500 - 300 * (T * 1000 / MAX_TEMP - 800)) {
+    if ((T = map_temperature(map_x, map_y)) > TROPICAL_LEVEL 
+       && myrand(100) >  50) {
       map_set_terrain(map_x, map_y, T_JUNGLE);
     } else {
       map_set_terrain(map_x, map_y, T_FOREST);
     }
+    forests_to_be_placed--;
     if (abs(hmap(map_x, map_y) - height) < diff) {
       cardinal_adjc_iterate(map_x, map_y, x1, y1) {
-       if (myrand(10) > 5) {
+       if (myrand(10) > 5 || (T > TROPICAL_LEVEL && myrand(10) >  5)) {
          make_forest(x1, y1, height, diff - 5);
        }
       } cardinal_adjc_iterate_end;
     }
-    forests++;
   }
 }
 
 /**************************************************************************
-  makeforest calls make_forest with random unplaced locations until there
-  has been made enough forests. (the map.forestsize value controls this) 
+  a recursive function that adds swamps to the current location and try
+  to spread out to the neighbours.
 **************************************************************************/
-static void make_forests(void)
+static void make_swamp(int map_x, int map_y, int height, int diff)
 {
-  int x, y;
-  int forestsize = (map_num_tiles() * map.forestsize) / 1000;
-
-  forests = 0;
-
-  do {
-    /* Place one forest clump anywhere. */
-    if (rand_map_pos_temperature(&x, &y,
-                                MAX_TEMP / 10, MAX_TEMP,
-                                T_NOT_PLACED)) {
-      make_forest(x, y, hmap(x, y), 25);
-    } else { 
-      /* If rand_map_pos_temperature returns FALSE we may as well stop
-       * looking. */
-      break;
-    }
-
-    /* Now add another tropical forest clump (70-100% temperature). */
-    if (rand_map_pos_temperature(&x, &y,
-                                7 *MAX_TEMP / 10, MAX_TEMP,
-                                T_NOT_PLACED)) {
-      make_forest(x, y, hmap(x, y), 25);
-    }
-
-    /* And add a cold forest clump (10%-30% temperature). */
-    if (rand_map_pos_temperature(&x, &y,
-                                1 * MAX_TEMP / 10, 3 * MAX_TEMP / 10,
-                                T_NOT_PLACED)) {
-      make_forest(x, y, hmap(x, y), 25);
+  if(swamps_to_be_placed <= 0) { return; }
+  if (not_placed(map_x, map_y) 
+      && ( 2 * (hmap(map_x, map_y) - seaval) < myrand(reliefval - seaval)
+       || (map_temperature(map_x, map_y) > DRY_MAX_LEVEL
+           && map_temperature(map_x, map_y) < DRY_MIN_LEVEL
+           && myrand(40) >  30))) {
+      map_set_terrain(map_x, map_y, T_SWAMP);
+      swamps_to_be_placed--;
+      if (abs(hmap(map_x, map_y) - height) < diff) {
+         cardinal_adjc_iterate(map_x, map_y, x1, y1) {
+         make_forest(x1, y1, height, diff - 5);
+      } cardinal_adjc_iterate_end;
     }
-  } while (forests < forestsize);
+  }
 }
-
 /**************************************************************************
-  swamps, is placed on low lying locations, that will typically be close to
-  the shoreline. They're put at random (where there is grassland)
-  and with 50% chance each of it's neighbour squares will be converted to
-  swamp aswell
+  a simple function that adds plains or tundra to the current location.
 **************************************************************************/
-static void make_swamps(void)
+static void make_plain(int x, int y)
 {
-  int x, y, swamps;
-  int forever = 0;
+  int T = map_temperature(x, y);
 
-  for (swamps = 0; swamps < map.swampsize; ) {
-    forever++;
-    if (forever > 1000) {
-      return;
-    }
-    rand_map_pos(&x, &y);
-    if (not_placed(x, y)
-       && hmap(x, y) < (maxval * 60) / 100) {
-      map_set_terrain(x, y, T_SWAMP);
-      cardinal_adjc_iterate(x, y, x1, y1) {
-       if (myrand(10) > 5 && !is_ocean(map_get_terrain(x1, y1)) 
-           && map_get_terrain(x1, y1) != T_SWAMP ) { 
-         map_set_terrain(x1, y1, T_SWAMP);
-         swamps++;
-       }
-      } cardinal_adjc_iterate_end;
-      swamps++;
-    }
+  if(2 * ICE_BASE_LEVEL > T || myrand(2 * COLD_LEVEL) > T) {
+    map_set_terrain(x, y, T_TUNDRA); /* in cold place we get tundra instead */
+  } else {
+    map_set_terrain(x, y, T_PLAINS);
   }
+  plains_to_be_placed--;
 }
 
-/*************************************************************************
-  Make deserts until we have enough of them.
+/**************************************************************************
+  make_terrains calls make_forest, make_dessert  with random free locations 
+  until there  has been made enough.
+ Comment: funtions as make_swamp, etc. has to have a non 0 probability
+ to place one terrains in called position. Else make_terrains can get
+ in a infinite loop!
 **************************************************************************/
-static void make_deserts(void)
+static void make_terrains(void)
 {
-  int x, y, i = map.deserts, j = 0;
+  int x, y;
+  int total = 0;
+  whole_map_iterate(x, y) {
+    if(not_placed(x,y)) {
+      total++;
+    }
+  } whole_map_iterate_end;
 
-  /* "i" is the number of desert clumps made; "j" is the number of tries. */
-  /* TODO: j is no longer needed */
-  while (i > 0 && j < 100 * map.deserts) {
-    j++;
+  forests_to_be_placed = total * map.forestsize
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize );
+  deserts_to_be_placed = total * map.deserts
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+  swamps_to_be_placed = total * map.swampsize
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+
+  /* tundra and plains is counted in map.grasssize */
+  grass_to_be_placed = total * map.grasssize / 2
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+  plains_to_be_placed = total /* and tundra */
+      - forests_to_be_placed - deserts_to_be_placed - grass_to_be_placed;
 
-    /* Choose a random coordinate between 20 and 30 degrees north/south
-     * (deserts tend to be between 15 and 35; make_desert will expand
-     * them). */
-    if (rand_map_pos_temperature(&x, &y,
-                                65 * MAX_TEMP / 100, 80 * MAX_TEMP / 100,
-                                T_NOT_PLACED)){
-      make_desert(x, y, hmap(x, y), 50, map_temperature(x, y));
-      i--;
-    } else {
-      /* If rand_map_pos_temperature returns FALSE we may as well stop
-       * looking. */
-      break;
+  /* the plasing loop */
+  do {
+    if(forests_to_be_placed > 0) {
+      /* Place one forest clump between Very Cold level and MAX_TEMP. */
+      if (rand_map_pos_temperature(&x, &y,
+                                  (COLD_LEVEL + ICE_BASE_LEVEL) / 2, MAX_TEMP,
+                                  T_NOT_PLACED)) {
+       make_forest(x, y, hmap(x, y), 25);
+      } else { 
+        /* If rand_map_pos_temperature returns FALSE we may as well stop
+         * looking for forest. */
+       plains_to_be_placed += forests_to_be_placed;
+       forests_to_be_placed = 0;
+      }
     }
-  }
+
+    if(swamps_to_be_placed > 0) {
+      /* Place one swamp clump between COLD_LEVEL and MAX_TEMP.. */
+      if (rand_map_pos_temperature(&x, &y,
+                                  COLD_LEVEL, MAX_TEMP,
+                                  T_NOT_PLACED)) {
+       make_swamp(x, y, hmap(x, y), 25);
+      } else { 
+        /* If rand_map_pos_temperature returns FALSE we may as well stop
+         * looking for swamp. */
+       plains_to_be_placed += swamps_to_be_placed; /* reactivate plains */
+       swamps_to_be_placed = 0;
+      }
+    }
+
+    if(deserts_to_be_placed > 0) {
+      /* Choose a random coordinate between TROPICAL_LEVEL and WET_LEVEL;
+        make_desert will expand them). */
+      if (rand_map_pos_temperature(&x, &y,
+                                  DRY_MIN_LEVEL, DRY_MAX_LEVEL,
+                                  T_NOT_PLACED)){
+         make_desert(x, y, hmap(x, y), 40, map_temperature(x, y));
+      } else {
+       /* If rand_map_pos_temperature returns FALSE we may as well stop
+        * looking for dessert. (convert to plains) */
+       plains_to_be_placed += deserts_to_be_placed;
+       deserts_to_be_placed = 0;
+      }
+    }
+
+    /* Make the grass */
+    if(grass_to_be_placed > 0) {
+      if (rand_map_pos_temperature(&x, &y,
+                                  COLD_LEVEL, MAX_TEMP,
+                                  T_NOT_PLACED)){
+       map_set_terrain(x, y, T_GRASSLAND);
+       grass_to_be_placed--;
+      } else {
+         plains_to_be_placed += grass_to_be_placed;
+         grass_to_be_placed = 0;
+      }
+    }
+
+    /* there is very important: this place all terrains when there
+       is not posibe for other types kip the 0, MAX_TEMP range. */
+    /* make the plains and tundras */
+    if(plains_to_be_placed > 0) {
+      if (rand_map_pos_temperature(&x, &y,
+                                  0, MAX_TEMP,
+                                  T_NOT_PLACED)){
+       make_plain(x,y);
+      } else {
+       /* If rand_map_pos_temperature returns FALSE we may as well stop
+        * looking for plains. */
+       plains_to_be_placed = 0;
+      }
+    }
+
+  } while (forests_to_be_placed > 0 || deserts_to_be_placed > 0 
+          || grass_to_be_placed > 0 || plains_to_be_placed > 0 
+          || swamps_to_be_placed > 0 );
+
+  /* final test */
+  whole_map_iterate(x, y) {
+    assert(!not_placed(x,y));
+  } whole_map_iterate_end;
 }
 
 /*********************************************************************
@@ -814,7 +921,7 @@
     if (adjacent_river_tiles4(x, y) != 0
        || adjacent_ocean_tiles4(x, y) != 0
         || (map_get_terrain(x, y) == T_ARCTIC 
-           && map_temperature(x, y) < 8 * MAX_TEMP / 100)) { 
+           && map_temperature(x, y) < 0.8 * COLD_LEVEL)) { 
 
       freelog(LOG_DEBUG,
              "The river ended at (%d, %d).\n", x, y);
@@ -1027,61 +1134,6 @@
   river_map = NULL;
 }
 
-/**************************************************************************
-  make_plains converts 50% of the remaining terrains to plains and 50%
-  grassland,
-**************************************************************************/
-static void make_plains(void)
-{
-  whole_map_iterate(x, y) {
-    if (not_placed(x, y)) {
-      if(myrand(100) > 50) {
-         map_set_terrain(x, y, T_GRASSLAND);
-      } else {
-         map_set_terrain(x, y, T_PLAINS);
-      }
-    }
-  } whole_map_iterate_end;
-}
-/****************************************************************************
-  Return TRUE if the terrain at the given map position is "clean".  This
-  means that all the terrain for 2 squares around it is either grassland or
-  plains.
-****************************************************************************/
-static bool terrain_is_clean(int map_x, int map_y)
-{
-  square_iterate(map_x, map_y, 2, x1, y1) {
-    if (map_get_terrain(x1, y1) != T_GRASSLAND
-       && map_get_terrain(x1, y1) != T_PLAINS) {
-      return FALSE;
-    }
-  } square_iterate_end;
-
-  return TRUE;
-}
-
-/**************************************************************************
-  we don't want huge areas of grass/plains, 
- so we put in a hill here and there, where it gets too 'clean' 
-**************************************************************************/
-static void make_fair(void)
-{
-  whole_map_iterate(map_x, map_y) {
-    if (terrain_is_clean(map_x, map_y)) {
-      if (!map_has_special(map_x, map_y, S_RIVER)) {
-       map_set_terrain(map_x, map_y, T_HILLS);
-      }
-      cardinal_adjc_iterate(map_x, map_y, x1, y1) {
-       if (myrand(100) > 66
-           && !is_ocean(map_get_terrain(x1, y1))
-           && !map_has_special(x1, y1, S_RIVER)) {
-         map_set_terrain(x1, y1, T_HILLS);
-       }
-      } cardinal_adjc_iterate_end;
-    }
-  } whole_map_iterate_end;
-}
-
 /****************************************************************************
   Lower the land near the polar region to avoid too much land there.
 
@@ -1122,6 +1174,21 @@
     }
   } whole_map_iterate_end;
 }
+/**************************************************************************
+ if there are room the isle is grownd by one else isle is deleted
+**************************************************************************/
+static void grown_tiny_isle(int x,int y, int nr) {
+  adjc_iterate(x, y, x1, y1) {
+    if(count_ocean_near_tile(x1,y1) == 7) {
+      map_set_terrain(x1, y1, T_NOT_PLACED);
+      map_set_continent(x1, y1, nr);
+      MASS_SIZE(nr)++;
+      return;
+    }
+  } adjc_iterate_end;
+  map_set_terrain(x, y, T_OCEAN);
+  return;
+}
 
 /**************************************************************************
   make land simply does it all based on a generated heightmap
@@ -1140,17 +1207,24 @@
       map_set_terrain(x, y, T_NOT_PLACED);
     }
   } whole_map_iterate_end;
-
   renormalize_hmap_poles();
   make_polar_land(); /* make extra land at poles*/
-  make_mountains();
-  make_arctic();
-  make_tundra();
-  make_forests();
-  make_swamps();
-  make_deserts();
-  make_plains();
-  make_fair();
+  assign_continent_numbers(); /* count sizes */
+  whole_map_iterate(x, y) {
+      int nr = map_get_continent(x,y);
+      /* avoid too small oceans */
+      if (is_ocean(map_get_terrain(x, y)) && MASS_SIZE(nr) < 8) {
+       map_set_terrain(x, y, T_NOT_PLACED);  
+      } 
+      /* avoid tiny isles */
+      else if (!is_ocean(map_get_terrain(x, y)) && MASS_SIZE(nr) == 1) {
+       grown_tiny_isle(x, y, nr);
+      }
+  } whole_map_iterate_end;
+
+  make_relief(); /* base relief on map */
+  make_arctic(); 
+  make_terrains();/* place forest/dessert/swamp/grass/tundra and plains */
   make_rivers();
 
   assign_continent_numbers();
@@ -1605,9 +1679,9 @@
 static void adjust_terrain_param(void)
 {
   int total;
-  int polar = 5; /* FIXME: convert to a server option */
+  int polar = ICE_BASE_LEVEL * 100 / MAX_TEMP;
 
-  total = map.mountains + map.deserts + map.forestsize + map.swampsize 
+  total = map.mountains + map.deserts + map.forestsize + map.swampsize
     + map.grasssize;
 
   if (total != 100 - polar) {
@@ -2314,6 +2388,22 @@
 #define DMSIS 10
 
 /**************************************************************************
+  make_plains converts 50% of the remaining grassland to plains, this should
+  maybe be lowered to 30% or done in batches, like the swamps?
+**************************************************************************/
+static void make_plains(void)
+{
+  whole_map_iterate(x, y) {
+    if (not_placed(x, y)) {
+      if(myrand(100) > 50) {
+         map_set_terrain(x, y, T_GRASSLAND);
+      } else {
+         map_set_terrain(x, y, T_PLAINS);
+      }
+    }
+  } whole_map_iterate_end;
+}
+/**************************************************************************
   island base map generators
 **************************************************************************/
 static void mapgenerator2(void)
diff -ruN -Xfreeciv/diff_ignore freeciv_/server/stdinhand.c 
freeciv__/server/stdinhand.c
--- freeciv_/server/stdinhand.c 2004-08-27 20:20:39.170422136 +0200
+++ freeciv__/server/stdinhand.c        2004-08-27 20:09:20.335620712 +0200
@@ -370,7 +370,7 @@
 
   GEN_INT("grass", map.grasssize,
          SSET_MAP_GEN, SSET_ECOLOGY, SSET_SITUATIONAL, SSET_TO_CLIENT,
-         N_("Amount of grass squares"), "", NULL,
+         N_("Amount of grass and plains squares"), "", NULL,
          MAP_MIN_GRASS, MAP_MAX_GRASS, MAP_DEFAULT_GRASS)
 
   GEN_INT("forests", map.forestsize,