Introduction
I saw what I thought was a very interesting idea about an adventure for a Tabletop RPG. The idea was to use the Lewis and Clark expedition to create an adventure.
I have been thinking something somewhat similar involving exploration of an unknown territory, but the Lewis and Clark expedition is definitely the right stuff for a Tabletop RPG. The Mississippi and Missouri river systems were not wholly unknown, but they had never been fully mapped, and the purpose of the expedition was to do so. Some aspect of such an adventure could be traveling across rivers, rapids, portage, hunting, dangerous natives, damaged equipment, disease, injury etc. etc. etc. With or without magic it makes for a great adventure.
I think adding to the concept of an empty map that needs to be filled in as you go would be perfect. Perhaps using a random terrain generator of a sort… as long as it didn’t result in some sort of dead-end or impossibility. Or perhaps just a real map that only the GM has and that is disclosed each hex at a time… so the party might get lost but can always get back on track to the proper route(s)?
How to do this? I asked around if anyone knew of a system, whether with or without a computer, that can generate a map on the fly creating terrain and routes of travel, or that can take an existing map, break it up into hexes, and that then provides a basis for a GM to disclose the contents of the hexes as the party travels into them?
I did not get a lot of feedback… so I sought the advice of our AI Overlords.
GROK
Here was the response I got from GROK:
Yes, there are several systems – both analog (pen-and-paper or physical tools) and digital – that support on-the-fly hex map generation for RPG adventures. These typically start with broad-scale terrain (e.g., continents or regions) and allow drilling down to individual hexes (often 6- or 24-mile scales for overland travel). They emphasize procedural or random elements so a Game Master (GM) can reveal hex contents dynamically as the party explores, using random tables, oracles, or modules to populate features like encounters, ruins, or terrain hazards on demand. Many draw from OSR (Old School Revival) traditions like those in the original D&D or Basic/Expert editions.
I’ll break this down by category, focusing on tools that fit your criteria: broad-to-hex generation, existing map overlays, and GM-driven disclosure.
Digital Systems for On-the-Fly Generation
These are web-based or software tools that procedurally create maps, often with export options (PNG/SVG) for virtual tabletops like Roll20 or FoundryVTT. They handle terrain types (e.g., forests, mountains) and basic travel routes (e.g., rivers, roads) at a regional level, then let you zoom into hex details.
Donjon Fantasy World Generator (free, web-based)
Generates a full regional or continental map with hex overlays, automatically placing terrain (mountains, plains, coasts), settlements, and natural features like rivers for travel routes. You can regenerate sections on the fly for unexplored areas. For hex contents, pair it with Donjon’s separate random encounter or wilderness tables to disclose features (e.g., “roll for lair or ruin”) as players enter. It’s ideal for quick prep and supports hex sizes from 10-100 miles.
HEXROLL (free tier available, web-based)
Creates an interactive OSR-style sandbox in seconds, starting with a broad hex map (terrain, biomes, and rough paths) that breaks into detailed 6-mile hexes. It auto-generates linked content like dungeon maps, NPCs, and treasures for each hex, which the GM can reveal progressively (e.g., fog-of-war style). Export as printable PDFs or images for table use.
HexLands (free, web-based)
A simple drag-and-drop editor for procedural hex maps. Start with a blank regional canvas, auto-fill terrain and routes via noise algorithms (like Perlin for natural-looking coasts), then subdivide into hexes. No built-in content generator, but it’s lightweight for on-the-fly tweaks and integrates with random table apps for GM disclosure.
FoundryVTT Modules (e.g., Procedural Hexploration)
For virtual tabletops, this uses dice rolls to generate adjacent hex terrain on the fly (e.g., “same as current or different?”). Broad maps import as overviews, with hex reveal mechanics for contents. It’s computer-dependent but excels at real-time GM improvisation.
Broader Generation
Tools like ‘Azgaar’s Fantasy Map Generator’ (free, web) can create continent-scale maps with hex exports, then feed into the above for hex-level details.
Analog Systems for On-the-Fly Generation
These rely on dice, tables, and physical aids, perfect for no-screen sessions. They use random rolls to build terrain coherently (e.g., ensuring mountains cluster logically) and provide tables for hex contents revealed during travel.
Procedural Terrain Generation System
A dice-based method where you seed a central hex with basic terrain, then roll 2d10 + modifiers from adjacent hexes to determine neighbors (e.g., +2 for hills encourages more hills). Start broad (sketch a 10×10 hex region), then detail travel routes (rivers flow downhill via rolls). For contents, roll on custom tables (e.g., 1-in-6 chance of encounter/ruin). Fully on-the-fly and printable on hex paper.
Hexcrawl Sheets or Exclusion Zone Botanist
Physical zines with random tables for generating hex terrains and routes (e.g., roll for biome adjacency). Draw broad overviews on hex graph paper, then populate hexes as entered using oracles for features (lairs, weather, NPCs). Designed for solo or GM use, with disclosure via “hex entry rolls.”
Forbidden Lands RPG Core Rules
A full tabletop system with built-in hex crawl mechanics. Use its maps (or draw your own) for broad terrain, subdivide into hexes via templates, and roll on included tables for on-the-fly contents (e.g., survival checks reveal hidden paths or dangers). No computer needed; includes physical map sheets.
One-Page Solo Engine + Hex Generator
A printable PDF toolkit with tables for procedural hex creation (terrain via dice chains, routes via flow logic). Roll to disclose contents per hex (e.g., “complication? Yes/No/And?”), making it adaptable for group play.
Other
Classic OSR resources like ‘The Hexcrawl Handbook’ (free PDF) or ‘Stars Without Number’ (free edition) provide table-based systems for this, emphasizing GM improvisation.
Overlaying Hexes on Existing Maps
If you have a pre-made map (e.g., a fantasy atlas or Google Earth export), these tools add hex grids without full regeneration, then support content disclosure via notes or tables.
GIMP (free image editor)
Follow tutorials to mosaic-filter an existing map into hex shapes, then overlay a transparent hex grid layer. Scale for broad (regional) to detailed (travel) views. Annotate hexes privately for GM reveals (e.g., hidden layers). Great for custom RPG maps.
Campaign Cartographer 3+ (paid, ~$50)
Import any image as a background, auto-overlay hex grids at any scale, and trace terrain/routes. Built-in tools for hex contents (e.g., symbol stamps for ruins) that you reveal by exporting views or printing keyed sheets.
Wonderdraft (one-time ~$30 purchase)
Load existing maps as stamps or backgrounds, add scalable hex overlays, and paint terrain adjustments. Supports dynamic views (e.g., fog-of-war exports) for GM disclosure during play.
Hexographer (free/pro versions)
Import images, snap a hex grid over them, and color-code terrains. Export with hidden keys for on-the-fly reveals.
Quick analog overlays
Print your map and use transparent hex sheets (available on Amazon) or draw grids with a lightbox.
Summary
These systems scale well for adventures – start with a 20×20 hex regional map for overviews, then generate 3-5 mile sub-hexes for local travel. If you’re using a VTT, combine with modules like Hex Kit assets for visuals. For more specifics, I recommend starting with Donjon for digital prototyping or the Hexed.it system for analog purity.
VENICE
Here was the response I got from VENICE:
There are several systems, both digital and analog, that can help generate maps on the fly for roleplaying games, breaking them down into hexes for easier management. Here are some options:
1. Hex Map Generation Tools
Inkarnate
This is a popular digital tool for creating maps. It allows you to draw and customize maps, including the option to use a hex grid. You can generate terrain features and then break the map into hexes for detailed exploration.
Wonderdraft
Another digital tool that offers a variety of terrain options and allows you to create maps with hex grids. It’s particularly useful for generating large-scale maps that can be broken down into smaller, explorable areas.
2. Random Map Generators
Donjon
This is a web-based tool that can generate random maps, including hex maps. You can specify the size and type of terrain, and it will create a map that you can then break into hexes for detailed exploration.
Hexographer
This is a desktop application that allows you to create hex maps. It provides tools for generating random terrain and can be used to break existing maps into hexes.
3. Analog Systems
Hex Tiles
You can use physical hex tiles to create a map on the fly. These tiles can be customized with different terrain types and can be arranged to create a variety of landscapes. As players explore, you can reveal the contents of each hex.
Dice and Tables
Use a random number generator (like dice) and tables to determine terrain and features. For example, you can roll dice to determine the type of terrain in each hex, and use tables to describe the contents of each hex as the party explores.
4. GM Tools
Roll20
This is a virtual tabletop that allows you to create and share maps with your players. You can use its drawing tools to create hex grids and reveal the contents of each hex as players explore.
Foundry VTT
Another virtual tabletop that offers extensive map creation and customization options. You can create hex maps and control what players see as they explore.
5. Hex Map Breakdown
Hexplorer
This is a tool that can take an existing map and break it up into hexes. It’s particularly useful if you have a detailed map and want to convert it into a hex grid for easier management during play.
Manual Breakdown
If you have an existing map, you can manually draw a hex grid over it. This can be done digitally using tools like Photoshop or Illustrator, or physically by printing the map and drawing hexes on it.
Summary
By using these tools and systems, a Game Master (GM) can generate maps on the fly, break them down into hexes, and reveal the contents of each hex as the party travels, providing a dynamic and engaging exploration experience.
Conclusion
I found it interesting how GROK and VENICE had some overlap, but also some unique items included. I think it is always a good idea to get a second opinion, and in this case it resulted in some interesting results.
