Mapgen V2.2

MapGen v2.2 is a widely used, though aging, tool designed to help modders create custom world maps for the grand strategy game Hearts of Iron IV (HOI4)

Here is a blog post detailing the update. mapgen v2.2

River & Erosion Simulation
New lightweight hydraulic erosion pass adds natural-looking river valleys and sediment deposits. MapGen v2

Inputs / Config

• seed: string or int (deterministic output)
• size: width: int, height: int
• scale: float (noise sampling scale)
• octaves: int (noise detail)
• persistence: float (noise amplitude falloff)
• lacunarity: float (noise frequency multiplier)
• elevation_range: min, max (world elevation bounds)
• sea_level: float (0–1 threshold)
• temperature_bias: float (-1..1)
• moisture_bias: float (-1..1)
• river_count: int or density
• river_smoothness: float (0..1)
• erosion_iterations: int
• coast_sharpness: float (0..1)
• feature_density: object (settlements, ruins, resources per 1000 tiles)
• biome_rules: adjustable thresholds or an evaluator function
• tile_resolution: enum low, medium, high
• wrap_x / wrap_y: booleans (toroidal map)
• seeded_rng: optional PRNG algorithm choice
• post_process_passes: ordered list of additional filters (splatting, smoothing, contouring)