May 202019
 

If you’re a landlubber like me, you have little to no idea how long it takes a ship to sail from one place to another. That will change by the end of this chapter, but we have considerable leeway in deciding the length of any journey. Much of what follows here is about travel under sail, or by rowing, not by engines. In fantasy worlds, those engines are implausible. In SF, travel is typically through the air. The speed calculations in the section on ship speeds can apply to engine-powered ships as well, since a knot is a knot and it doesn’t matter what’s causing this speed, with the caveat that winds and oars cannot produce the constant speed of engines.

Several factors influence the difficulty of sailing between locations. The wind direction is chief among them. The ship building skills and seamanship of various countries also impacts this. All of it influences trade routes and which nations can conquer others. A ship would not be able to sail directly into a headwind. Taking an alternative route might force a ship closer to an enemy coastline.

There are several reasons we have leeway in determining the duration of a ship journey:

  1. Our map, should one exist, is not drawn to scale
  2. Oarsmen cannot row indefinitely and might have different levels of endurance and training from ship to ship
  3. Wind speed is not constant even in the open ocean, affecting both the ship itself (if sail powered) and the height of waves that could further impact speed
  4. Wind direction is also not constant, affecting the angle at which wind fills sails
  5. Different types of ships sail at different speeds under the same conditions
  6. Our ship is weighed down by people, cargo, food, and weapons/ammunition, any one of which can change in quantity during a voyage. A ship that just left dock is heavier than one at sea for six months, unless the latter is laden with treasure
  7. Our ship might be damaged
  8. Our ship is sailing on a fictitious planet, with possibly a different number of moons and whatever else might affect the seas

Maybe it comes as no surprise that we aren’t sure how long a trip will take. What we’re looking for is a reasonable approximation that a ship will take between X and Z number of hours to travel Y number of miles/kilometers, depending on conditions. But we don’t have to do this. We can just invent numbers and not worry about it. Never stating the distance between two places helps this. Grounding our numbers in some real-world knowledge is an approach that more serious world builders might want to employ, especially if we intend to reuse the setting. Otherwise, we might be inconsistent. Regardless of our choice, the knowledge can help inspire believable details in our work.

For example, let’s say that for our story, we need a trip to take 24 hours, but our calculations reveal that a ship usually takes 24-30 hours. We’re in luck and can do it. When describing that journey, we could state that our sailors enjoyed nearly ideal conditions. This could allow for characters to undertake sword practice on deck or another activity requiring surer footing. A wizard could have time to mix materials needed for spells.

In another scenario, maybe we want our characters to feel confident they’ll make that trip in time. But we want to surprise them and make them arrive late, in 34 hours. We can throw up a storm to slow them, making a character sea sick and preventing others from doing much of anything. Or maybe they battle a ship or sea monster and in so doing lose a mast despite their victory.

We don’t have to do these things, but stories always need unexpected challenges, and if the sea isn’t hard to predict, nothing in our world is.

May 022019
 

Determining the distance between locations for which we want to calculate travel times should be an early decision. Take terrain changes between each pair of locations into account. Then decide which travel methods will be used in your books; there’s no sense in calculating dragons’ travel time if they don’t exist in your world. Review the base miles per day that this book provides and alter them to suit your judgment. Do the same for terrain and other modifiers. Now you’re ready to calculate the travel times. The easiest method is to use the pre-set ones provided. Otherwise, carefully study the equations in this chapter and the Excel spreadsheet and apply them as needed.

Apr 292019
 

On the template, there’s another sheet called “Regions.” This sheet allows us to figure out how many miles (or kilometers) long and wide our land features are, and the total square miles or kilometers. Though this has nothing to do with travel, this chapter’s subject, it’s on the same template to make use of the Schema sheet. Most of us likely won’t care about the total square miles of land in a region or sovereign power, but for those who do, this sheet calculates it for you.

Here is a screen shot:

Figure 47 Region Sizing

Figure 47 Region Sizing

Measure the length and height of each sovereign power or land feature on a continent. This will help you learn how big everything is. With the inches columns filled in, we can once again use the Schema sheet to determine how many miles and kilometers everything is by referring to the appropriate cells. In the image above, you can see “Continent Name” is fifteen inches long. Since I don’t have fifteen inches on Schema (I stopped at 2.75), I used math to get my fifteen inches. In other words, the calculation is for two inches multiplied by seven (to get fourteen inches), then one inch being added to it. For example, =ROUND((Schema!B9*7)+(Schema!B5),1). The same was done for height. Doing it this way once again means that if I ever change the scale of my map, these numbers change for me.

The calculation for square miles/kilometers is done by multiplying the values for length by height. However, this assumes your land feature is a square or rectangle when it probably isn’t. The solution for this is another multiplication, this time by a percentage represented by a decimal value. For example, if we have a forest that is 100 miles by 80 miles, the square miles would be 8,000 (100 * 80). However, maybe it’s not an actual rectangle, so we decide ten percent of that area is not included in the territory. We’d change the calculation from 100 * 80 to (100 * 80) * .9, resulting in 7,200 square miles. The same modification is done to square kilometers. This example is in the spreadsheet for “Forest #1 Name” under “Kingdom #2 Name.”

Lastly

When experimenting with this spreadsheet, be careful of the way Excel works. We can accidentally change the formula in a cell if we click elsewhere. It’s best to use the tab key to navigate out of a cell with a formula.

Apr 252019
 

Most templates for this book are Microsoft Word documents that are downloadable but also printed in an appendix. For the travel calculations, there is a Microsoft Excel spreadsheet instead, which I discuss here. You can join the newsletter and download the “Travel Template” for free at http://www.artofworldbuilding.com/newsletter.

This section explains how the Excel file is set up, including the schema sheet that sets defaults, the travel sheet for distance calculations, and the manual travel sheet that lets you do your own thing.

Calculating Travel Times

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Apr 182019
 

Now we need to calculate the number of days it takes to travel between two points on our map. The formula is distance divided by speed. First, we need to calculate speed by taking the BMPD and subtracting the amount of time lost by the terrain traveled over. The resulting formula is:

Distance / (BMPD—Terrain Modifier)

For example, traveling by foot is 12 miles per day. According to my chart, if traveling through light forest without a road, we lose 1.8 miles per day, resulting in a speed of 10.2 miles per day. If our map’s scale says that a quarter inch is 20 miles, and our journey is 1 inch, then 20 * 4 is 80 miles. Eighty (80) miles divided by 10.2 miles per day gets our answer: just under 8 days.

80 / (12—1.8)

Calculating speed for every mode of travel, through every type of terrain, for every two locations on our world, can be time consuming. Doing so has an advantage: once the calculations are done, we don’t have to do them again. If we change our mind about scale and have used the provided spreadsheet to track our data, then our calculations will automatically update. This method might be more suited to those intending to use a world over many stories.

By contrast, there is a more manual method, discussed in the next section, that avoids using formulas to change things. Its chief disadvantage is that if we change our mind on scale, calculations we’ve logged before must be redone. Those using a world once or twice might find this is the most suitable approach.

Pre-Set Calculations

The easiest approach to calculating travel between two places is to be generic about it. Looking at the chart below will make the explanation clearer. This chart states in line 1 that everything on it is for traveling on a paved road. Column A shows inches on our map, while columns B and C shows the corresponding number of miles or kilometers; which we use is irrelevant for determining speed. Columns D through J are the number of days to travel each distance from the first three columns by foot, riding horse, etc.

This chart, and others for different terrains, is included in the free template given to newsletter subscribers. The file allows you to change the scale so that .25 inches could be 25 miles instead of 20, for example, and all the chart’s data will change immediately.

Figure 39 Travel on Paved Roads

Figure 39 Travel on Paved Roads

Using these pre-set calculations, we never need to use formulas to determine travel time. Instead, we can take our measurement between two places, like Illiandor and Talendor, and see that it is 2 inches. Line 11 above shows us how far that is and how long each travel mode is. And we’re done.

But what if the two inches between these locations are over different terrain? Maybe 1 inch is a road and another inch is rolling hills. We need to grab line 7 from both charts (the line for 1 inch). Now we have realistic data with thought behind it.

In the included template, I’ve added an area for you to add up these values. It looks like this screen shot below. What I did here was take the inches by road and hills and typed them into the chart. Then I add the miles by looking at the other charts. I also added the values for a riding horse, in this case. It shows my final results for a particular journey.

Figure 40 Travel Sample

Figure 40 Travel Sample

The main problem with the above chart is that our data is not preserved. When we want to do a second journey, we’ll have to replace that data, unless we save it somewhere. Also, if we change our mind about scale, that saved data must be redone. For this reason, some world builders might want to follow the steps in the next section.

Custom Calculations

World builders who intend to use the world for many years to come might want to preserve travel times between many places in a single database. Doing this requires a time investment and familiarity with formulas that will scare away many people. This section is designed for the brave. I did this once for my main world, Llurien, and will likely never do it again, even for new continents, because it’s too much work. There’s also a significant risk of making a formula mistake. A major advantage of doing it is that, once done, it never needs repeating. A change of scale updates the entire spreadsheet.

The details of these custom calculations are discussed in the following template section. Explaining how to do it without the template as a visual guide is unnecessarily challenging. And setting up that template yourself is more pain than you likely want.

Terrain Modifiers Part 2

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Apr 152019
 

This section offers calculations for how to modify the number of hours it takes to reach somewhere based on the type of terrain.

Determining Map Scales

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Apr 112019
 

This section talks about how to create a believable scale for your maps, leveraging real world places that we’re familiar with.

Measuring Distances on Your Maps

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Apr 082019
 

This section talks about how to get organized with your measurements, and how to take them, when creating a log of how far apart various settlements and land features are in your setting. This helps you be consistent – and realistic.

How Terrain Impacts Travel

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Apr 042019
 
The Impact of Terrain

The terrain we travel over impacts our speed and even reliability. Sand will impact a two-legged species less than a wagon, with wheels that are bogged down, but remember, from Chapter 4, that most deserts are rocky rather than sandy. A forest with thick underbrush slows everything. A light forest will have less impact. The density of underbrush in a forest is a moot point if there’s a cleared road through it. Rolling hills, foothills, and mountains will slow everyone whether there’s a road or not; it takes time to go up and down and this is worse on the legs of humanoids or animals, increasing fatigue.

Roads paved with cobblestones aren’t very smooth and can not only slow travel but fatigue feet and even wagons, where the bumpy ride strains construction. Such roads are more common near a city, extending only a short distance from the walls. Very dry, hard ground is tough on feet, which is why horses will prefer the grass. An unpaved roads means potholes and potentially mud.

Paving, when present, seldom extends far from a settlement due to expense. This is one way to indicate wealth, such as in an empire. We may want to decide that most roads are unpaved for most of their length.

Rivers can require traveling to a known crossing, which might be guarded by creatures or species who charge a toll or simply won’t let others pass without a fight. Given fords’ importance, such a crossing might be controlled by a city, sovereign power, or band of opportunistic thugs. But our main concern is to decide where a river crossing is between two settlements and measure the distance to it from both places, unless the bridge happens to be directly between them.

The Impact of Life

Wild animals and sinister species make traveling more perilous. On a wide open plain with low grass, one could see trouble coming from a long way off, but tall grass or a thick forest could slow our travelers even if there’s a road through the terrain. Due to this, there’s a difference between the theoretical travel time and the actual. This is another way to slow our characters.

Getting Around By Flying

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Apr 012019
 

While flying can generally be assumed to be done in a straight line, factors change this, though this depends on the mode of travel, as what affects a dragon wouldn’t affect a Boeing 747. Mountains can be tall enough that they must be circumnavigated. Real birds struggle to get over the Himalayas, for example, because the air is thinner. Dragons are often depicted as all-powerful, but describing their difficulty in climbing over mountains is one way to make them more realistic. This is one reason, along with rain shadows, for characterizing any land features we’ve created; in this case, we’ll decide which mountain ranges are this tall (hint from Chapter 4: the tallest peaks are in the interior of a continent, not on its coast).

Hostile territories can also change flight patterns, whether that hostility derives from other animals or sentient beings like humans with missile weapons. A lone dragon might fear to fly through an area inhabited by other dragons, if the latter are territorial or of a hostile variety. If the dragon is unafraid, his rider might be more cautious.

Politics can also cause hostility. A dictatorship might have outlawed all dragons, for example, that aren’t ridden by its own military so that borders are closely watched. Being caught could be a problem. While some might attempt passing over the territory using flight or subterfuge, some will simply go around. In such cases, we’ll need to figure out the shortest path that is not a straight line.

Animals

All flying animals that are depicted as being ridable are imaginary. The likelihood is that none of them would get off the ground with a rider, but there’s no fun in that. We must take being realistic with a bigger grain of salt than normal, but the useful details and considerations that arise from trying to be realistic can make our work more believable.

Except for mountains, flying animals are unaffected by the terrain, whether that’s roads, forests, rolling hills, or deserts. Flying low changes things a little, as foliage may hide threats, but we’re focused on speed here, not dangers except as those that affect flight paths.

When deciding how far (and fast) invented animals can travel in a day, it can help to start with understanding what real Earth birds can do. A carrier pigeon can fly about fifty miles per hour and cover seven hundred miles in a day. Hawks reach twenty to forty miles per hour during migration. These guidelines can help us determine the speeds and distances of our invented fliers. If we have a species that is humanoid with wings, aerodynamics will ensure they fly more slowly than birds. Their maneuverability is also reduced so that a giant bird should have little trouble catching and killing our species, unless the latter is well armed with missile weapons. For these reasons, flying low and hugging treetops and mountains is wiser for our humanoid character than open air unless they have no reason to suspect such a foe. The sight of such a threat should prompt one to seek shelter.

Airships
Figure 33 Zeppelin Airship

Figure 33 Zeppelin Airship

Whether we call them airships, blimps, or dirigibles, these aircraft use buoyancy to stay aloft. This chapter won’t focus on the differences between them but rather how fast they can travel. The larger airships like the Hindenburg have higher speeds and other capabilities. The Hindenburg before its demise could reach 84 mph (135 k/mh), but smaller blimps are a bit slower—their maximum speed is 70 mph and with a typical cruising speed of 30-50 mph. The limitation is inherent in the shape and design; using a bigger or more powerful engine won’t change this.

As opposed to a balloon, they are maneuverable. The large ones can ascend as high as 24000 feet (7300 meters), which means they can theoretically fly over any mountain range on Earth. However, their payload is reduced when that high and they mainly operate between 1500-8000 feet (460-2500 meters), though the Hindenburg typically did so under 650 feet to stay below clouds and monitor them for storms. The purpose of the flight will determine their altitude, as a passenger ship might sail lower to provide views while a surveillance blimp might be higher to avoid detection.

When planning a trip for our characters, we can assume a straight line unless we have some reason not to do so, such as the avoidance of a storm or hostile territory. Airships must refuel and this could restrict their uninterrupted flight to 24-50 hours, but the Hindenburg could fly over 100 hours, typically when crossing an ocean.

Balloons

Hot air balloons drift with the wind. They cannot be propelled through the air and their flight path cannot be controlled beyond a limited degree. Their speed is also rather slow, such as 3-6 mph for commercial flights, which range from 3-10 miles long and take roughly an hour. Longer trips are possible as the Earth has been circumnavigated in a single trip more than once; fuel, supplies, assistance, and navigator skill are the requirements for such a feat. For world builders, we mostly need to know the balloon’s air speed and what sort of trouble our characters might get into if the flight doesn’t go as planned, but this will depend on landscape.

Airplanes

There are many variations to planes and engine types that will determine how long it takes to travel between two locations by aircraft. This includes fuel capacity, wind, and the plane’s purpose, as a passenger jet is far slower than an F-16, but also far faster than a crop duster. The variety is extreme enough that trying to summarize this may not serve a world builder well and has been omitted from the book.

What we need to first do is decide on the technological level of our society and what sort of plane we need (passenger, fighter). What’s the purpose in our story, and do we want our characters to have a plane that suits that purpose or not? Perhaps only a two-seat propeller plane is available but they’d prefer a fighter jet. We’ll also need a sense of how far they need to go. From here, we’d Google the plane type, learn its typical speed and fuel capacity, and get a sense of how long a trip might take if done in a straight line.