D&D 5e – Questionable Arcana – Crafting: Cartographer’s Tools

IMPORTANT NOTICE: Although this crafting system leverages many existing mechanics published under the 5e SRD and OGL, the final product is completely home-brewed. The finer details of this system are still being revised, and those changes will slowly be introduced into this document. However, the system as a whole is totally functional and ready to be used in any campaign. Furthermore, the rules and concepts discussed are intended to work in-tandem with the expanded artisan's tools rules found in Xanathar's Guide to Everything. If nothing else I hope this document and its siblings can be used as a source of guidance and inspiration for whatever crafting system you decide to go with.

Having finished our lesson on creating the best jewel studded finery the world has to offer, I want to change course a bit by looking at the artisan’s tool that can be used to change the course a campaign. This means the cartographer’s tools are the next step in our journey to understand the ill-explained world of crafting in 5th edition. As usual before we veer down the trail of the mechanics of the kit, I want to make sure we understand how cartography worked in the medieval era vs today.

Anybody who has compared historical maps to their modern counterparts knows that back in the day map-making wasn’t an exact science. Traditionally this process was completed by surveyors who would trek across the land and use heavy equipment to estimate the dimensions of geographical features via triangulation. When possible the surveyors would utilize objects whose dimensions were known to speed up the measuring process, otherwise they would be stuck painstakingly measuring objects to create new reference points. This usually involved trooping up and down mountains in an attempt to get a base measurement of the width/height, then using those values to triangulate the dimensions of objects around the region.

Mapping latitudinal and longitudinal segments of the map typically required the cartographer to triangulate off of points in the sky. The relatively fixed position of The North Star resulted in maps that were fairly accurate from a north to south stand-point, but figuring out the longitude is trickier because the earth’s rotation doesn’t allow for a corresponding East or West star. Cartographers worked around this by tracking where the sun and the stars were at a given time of day and used the time and location to zero in on their horizontal position. Using this methodology map-makers were able to get a rough estimate of the east-west dimensions of a region, but usually their results were fairly inaccurate.

Now days map-making is a much more straight-forward process. Advancements in photography, aeronautical transportation, and ultimately satellite imagery has greatly improved both the accuracy and throughput of map-makers. As a region’s structural and geographical details change we are able to update the maps we use in a span of days and weeks instead of months. This ability is being enhanced further with the advent of LIDAR and drone technology.

So How Am I Supposed To Use This Information In Game?

Unless you are running a very unforgiving wilderness-survival style campaign and/or you have a great deal of confidence in your understanding of map-making, I recommend you ignore most of the details above. Instead let’s use those details to break down the map making process into a couple of basic rules, and then try to plug these rules back into the crafting process as a whole. However, before we dig into the actual mechanics of creating a map, it is important to establish what a map actually does.

Maps are one of the most versatile storytelling tools a DM has in their repertoire. Entire adventures are often kicked off once the party finds a map that guides them to a point of interest. Finding your way to a point of interest usually involves overcoming a series of obstacles including monsters, environmental hazards, and navigational ability checks. The first two obstacles I described are generally managed by the full suite of game-play mechanics, however the ability to navigate the party through the wilderness often comes down to a simple dice roll.

When tracking down a point of interest a map usually serves as an enabler. Without the map the party would likely not be able to find their way to the cave, waterfall, or otherwise distinct point of the world that moves the adventure forward. Fortunately for the party it is reasonable to assume that all adventurers are able to attempt to navigate the party using a map. However, I would argue that anybody who is proficient in the craft of cartography would have a leg-up on your average adventurer when reading a map. As a result I would recommend adding that player’s cartographer’s tools proficiency bonus to any skill check that involves reading a map.

The Takeaway: Add the characters Cartographer’s Tools proficiency to any check involving reading a map.

Creating Maps – Rules as Written

The official guides are fairly light on the rules behind map making. Other than a few passing references to maps and how they might be used, the only time the actual map creation process is mentioned is on page 183 of The Player’s Handbook under “Other Activities” while traveling. In this section it states that any player can draw a map while traveling, and that no ability check is required. However, the only stated functionality of a map drawn this way is to help the party get back on course should they get lost.

For crude maps drawn this way I recommend sticking to the rules a written. All but the dimmest of adventurers should be able to create a basic map that helps the party retrace their steps.

The Takeaway: Following the rules in the PHB on page 183, (mostly)any player can create a roughly drawn map to help the party backtrack through the wilderness.

Creating Detailed Maps

The process of creating detailed topographical or physical maps is never covered in any of the D&D core rule books. Unlike the hastily drawn sketches mentioned in the player’s handbook, these high quality maps require a great deal of time and skill to create. As we covered above, this process typically involves leveraging complex instruments, and measuring large areas via triangulation. As a result I recommend creating a separate process for these more detailed maps.

This process is broken down into 3 basic steps:

1. Starting a mapping session.
2. Traversing the area being mapped.
3. Ending the session and rolling the cartographer’s tools check.

As long as the Cartographer is awake they can begin a map making session at any time. Before the map making session begins the Cartographer must explain to the DM the area of the world they are trying to map. The DM then uses this description and their knowledge of the world to secretly determine the difficulty check the Cartographer needs to beat. This check is not rolled until the end of the session.

Once the session begins the Cartographer attempts to map everything they can see in the surrounding area. During the session the Cartographer cannot make passive perception checks and has disadvantage on all active perception checks not related to the creation of the map. The session continues until the DM decides that the player has completed surveying the land, or the player voluntarily terminates the session.

Once the session ends the player then rolls a cartographer’s tools ability check to determine the quality of the map. Before the roll is taken the DM should take into consideration any events that happened during the mapping session, and modify the difficulty check accordingly. The degree to which the check is modified is up to the DM, but events that would make mapping more difficult(combat, obscured vision, etc…) should increase the DC, and events that aid in drawing maps(high elevation, familiarity with the region, etc…) should lower the DC required. If a player voluntarily terminated the session, they are still able to attempt to map the area they were able to traverse. However, the DC they must beat is still based on the initial secret value. This means that the check will usually be more difficult than if the cartographer had chosen to focus on mapping a smaller area to begin with.

Once the DC is determined the ability check is rolled. Instead of a binary pass/fail system the DM should keep track of how well the player rolled vs the DC required. Depending on how well the player rolled the DM will then secretly track the quality of the map by assigning it a + or – value based on the ability check. As an example if a player needed to beat a 16 but ended up rolling a 19, the DM would secretly mark the map of the area as a map+3. This hidden score would then be used as a secret modifier when the DM resolves any ability checks using that map. Upon map completion a player is able to reveal the quality of the map if they are able to win an insight check against the DC required to create the map.

The Takeaway: Creating a map requires the player to participate in a map making session. A session can be started at virtually any time, and requires the player to observe a region. At the end of the session the player must make a cartographer’s tools ability check to determine if they were successful in creating an accurate map.

Selling A Map

After acquiring or creating a map the character may decide that they want to sell it for a profit. For non-decorative maps the value of the map is determined by the quality of the information. For example, a map containing a detailed layout of a town or stretch of land might sell for small amount of gold at a cartographer’s guild. However, a map leading to a long lost treasure in a forest might be worth a small fortune.

The catch to selling maps is that the buyer needs to believe in its value. This generally comes down to the seller’s ability to persuade the buyer that the map is legitimate. For real maps I recommend having the seller roll a persuasion check while the buyer rolls an insight check. The persuasion check is used to determine how well the seller presents the map to the buyer, and the insight check gives the buyer an idea of how accurate the map is.

Because this is an honest transaction these checks are technically not a contest, however extremely low rolls on persuasion or insight(failing the check by 5 or more) might result in the buyer doubting the legitimacy of the map. I recommend you use the same DC used at the end of the map making session to create the map as the starting point for the persuasion and insight checks. This makes sense because the more ambitious the map is, the more difficult it will be to convince the buyer that the information is accurate. From there you should use other external factors such as the relationship between the buyer and seller, the seller’s reputation as a map maker, the buyer’s knowledge of the area, etc to adjust the difficulty check up and down.

If the player believes that the quality of the map is suspect but wants to sell it anyways, then the a deception vs insight contest should take place. If the seller wins the contest, then the buyer believes the map is real, and the sales process detailed above can begin.

The cartographer might decide to make a copies of the map for either personal use or resale. This behavior should be allowed, however a couple of restrictions should be put in place when selling multiple copies of the same map. The first restriction is limiting who you can sell the map to. Although anybody could technically become a buyer, in most cases there will be only one or two buyers in an area who will pay top dollar for the information provided on the map. As a result there should be some pretty serious diminishing returns when scrapping the bottom of the proverbial sales barrel for new buyers. Also some maps such as maps to hidden treasure are often valued because of the exclusivity of its contents. A would-be treasure hunter would likely be upset if they found out that they might not get a return on their investment because the party was selling copies of the map to other treasure hunters around town. At minimum this would lead to a devaluation of the information on the map, but it also could result in an unpleasant encounter or two from disgruntled buyers.

Or You Can Just Hang The Map Up On A Wall

Another effective way to sell a map is to treat it like artwork. The cartographer might be or know an excellent artist or calligrapher who can turn their map of the city into a work of art. When taking this approach I recommend you use The Questionable Arcana Artwork Crafting System or something similar to facilitate the creation of the artwork.

It is important to remember that being a cartographer is different from being an artist. A character who only has proficiency in the cartographer’s tools will not be able to turn it into a beautiful painting on their own. However if they have a painter leading the creation of the artwork, It is fair to assume that the cartographer could assist in its creation.

The Takeaway: When selling a map the seller must be able to convince the buyer of the value of the map. This is done with a series of persuasion, deception, and insight rolls. A map can also be turned into a work of art, but it requires somebody with an artistic bent to lead the creation of the artwork.

Conclusion

Someone with proficiency in the cartographer’s tools can be a great boon to a party. Not only can maps they make be used to help prevent a party from getting lost, but this proficiency also gives the player an edge when reading maps created by others. Furthermore the ability to sell both basic and artistic maps makes the cartographer’s tools one of the best artisan’s tools available in game.

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