Here is a quicky list of command switches....
Usage: ./dommap <options>
-v (for verbose mode)
-h <map height> (100-2400)
-w <map width> (100-3200
-n <map name>
-s <random seed>
-r <terrain ruggedness>
-sr <Shadow map ruggedness>
-wl <water line (0-100)>
-tl <tree line (0-100)>
-ml <mountain line (0-100)>
-pl <poverty line (0-100)>
-rl <rich line (0-100)>
-d <terrain dithering>
-ns <num of sea provinces>
-nl <num of land provinces>
-ps <percent special shape provinces>
-sa <min distance from shore (sea)>
-la <min distance from shore (land)>
-ss <distance between sea provinces>
-ls <distance between land provinces>
-sc <cost for spreading over shore>
-tc <cost for spreading over terrain>
-sm <amount of border smoothing>
-ln <minimum neighbours for starting (land)>
-sn <minimum neighbours for starting (sea)>
-imp <fraction impassable borders (0.0-1.0)>
-th3 (use triple-thickness for impassable borders (default))
-th2 (use double-thickness for impassable borders (default))
-ssi <1 = allow sea-sea impassable borders, 0 = not allowed>
-ms <fraction provinces marked as ManySite (0.0-1.0)>
-nfw (do not prevent all land pixels in sea provinces - default)
-fw (all land pixels in sea provinces are converted to sea if smoothing is on)
-ba <on|off> Turns additional shading on or off (default is on)
-bw <on|off> Turns additional shading of water on or off (default is off)
-beb <0-255> Max amount to brighten a color due to elevation-map
-bes <0-255> Max amount to shade a color due to elevation
-bsb <0-255> Max amount to brighten a color due to shadow-map
-bss <0-255> Max amount to shade a color due to shadow-map
-c_plains <0xrrggbb Sets the colour of plains to the specified RGB hex value>
-c_water <0xrrggbb Sets the colour of water to the specified RGB hex value>
-c_mountain <0xrrggbb Sets the colour of mountains to the specified RGB hex value>
-c_farmland <0xrrggbb Sets the colour of farmland to the specified RGB hex value>
-c_forest <0xrrggbb Sets the colour of forests to the specified RGB hex value>
-c_swamp <0xrrggbb Sets the colour of swamp to the specified RGB hex value>
-c_tundra <0xrrggbb Sets the colour of tundra to the specified RGB hex value>
-c_wasteland <0xrrggbb Sets the colour of wasteland to the specified RGB hex value>
-c_land_border <0xrrggbb Sets the colour of land borders to the specified RGB hex value>
-c_sea_border <0xrrggbb Sets the colour of sea borders to the specified RGB hex value>
-sps <max fraction of average province size to be a small province (0.0-1.0)
-lps <min multiple of average province size to be a large province (1.0+)
-blank (produce a 'blank' map: no (visible) terrain except sea, plains)