Factorio Console Script: Fill in lake(s).

factorio_fill_lakes.lua

game.player.print("Getting player position...")
local player_position = game.player.position
game.player.print(string.format("Player is at x=%.3f, y=%.3f", player_position.x, player_position.y))

game.player.print("Checking for neighbouring water tiles...")
local neighbouring_water_tiles = {}
for x=player_position.x-1,player_position.x+1 do
    for y=player_position.y-1,player_position.y+1 do
        local t = game.player.surface.get_tile(x,y)
        if t.name == "water" or t.name == "deepwater" then
            table.insert(neighbouring_water_tiles, {x=x, y=y})
        end
    end
end
game.player.print(string.format("Found %i neighbouring water tiles", #neighbouring_water_tiles))

local first_neighbour = neighbouring_water_tiles[1]
game.player.print(string.format("First neighbouring water tile at x=%.3f, y=%.3f", first_neighbour.x, first_neighbour.y))

game.player.print("Finding all water tiles that are connected to first neighbour...")
local connected_water_tiles = game.player.surface.get_connected_tiles(first_neighbour, {"water", "deepwater"})

game.player.print("Replacing water tiles...")
local replacement_tiles = {}
for i, p in ipairs(connected_water_tiles) do
    if p.x % 2 == 0 then
        if p.y % 2 == 0 then
            table.insert(replacement_tiles, {name="refined-hazard-concrete-left", position=p})
        else
            table.insert(replacement_tiles, {name="refined-hazard-concrete-right", position=p})
        end
    else
        if p.y % 2 == 0 then
            table.insert(replacement_tiles, {name="refined-hazard-concrete-right", position=p})
        else
            table.insert(replacement_tiles, {name="refined-hazard-concrete-left", position=p})
        end
    end
end
game.player.surface.set_tiles(replacement_tiles)