Cartography is the study and practice of making maps. It involves understanding and charting landscapes and transcribing it onto paper. Maps come in a variety of sizes. City and regional maps are most common as they provide the traveller enough information to get to where they are going. The smallest of maps tend to be single plot property maps to confirm ownership of a plot of land. Whereas true masterpieces can cover entire continents or the rare world map.
Geometry and scale are important aspects to cartography. By nature, all maps have a scale, as they sized to represent the land that is much larger than the parchment itself. To produce maps with reliable and consistent scale is another matter and it takes a low level of mathematics to properly scale maps. Scales are typically described as how many miles are represented by an inch on the paper. Geometry is used when charting locations based on a compass direction or comparing different landmarks by means of sightlines. Rhumb lines are the term for lines on a map drawn at a specific angle compared to the horizontal lines of latitude. For example, parallel lines drawn at a 45 degrees angle (along the NE cardinal direction) are called Rhumb lines.
Elevation can be depicted on maps in a variety of ways. More simplistic maps use mountain or hill symbols to depict elevated terrain. More sophisticated maps sometimes use contour lines to show elevation. Contour lines are lines at which a constant elevation is maintained. These are typically spaced at regular increments, for example every 10 feet in height. When contour lines are densely placed on a map, it represents a very steep slope or cliff, and where they are spaced further apart, the slopes are flatter.
There are several geographical principles that should be noted when constructing a map. Mountains typically form ranges or at least clusters, and it is less common to have a single isolated mountain. Rivers always flow downhill, unless acted upon magically. This means they start in high places like in mountains and outlet at the sea. Tributaries of rivers tend to converge and join the main river. The only key exception where rivers diverge, is where there is a delta at the mouth of the river, which can form when the land is exceptionally flat near the outlet. While roads can be built in any configuration, they typically connect key landmarks such as cities in regional maps, or key buildings or districts within a city map.
What makes a quality map?
The quality of a map is based on three main elements: accuracy, level of detail, and overall aesthetics. In general, poor quality maps are low in all these areas and as these areas improve then the quality improves. Not all of these traits need to be identical in level, as it’s plausible for a map to have a lot of detail but not be accurate, or accurate but not aesthetically appealing.
Accuracy refers to how well the map reflects the actual landscape. The level of detail refers to how many landmarks, cities, rivers, mountain ranges, etc. are included in the map. This can also apply to the level of detail in city maps in which roads or shops are depicted. The aesthetics are the overall look and usually correlate more strongly with the cartographer’s drawing skill.
Types of Maps
Maps range in size from single lot property maps, to city maps, to regional maps, to world maps. Each can have varying degrees of detail appropriate for the land area they cover. Specialized maps can have themed information for a specific purpose. For example, a wilderness map may cover a whole region and focus on elements such as trails, key places of passage like fords and mountain passes, and places to find food or shelter. Whereas a military map may focus on fortifications, roads, places of strategic military terrain and potentially the current whereabouts of enemy and allied forces. Ocean maps may have a strong focus on coastlines, trade winds, and hazardous features in the water. These are just a few examples of themed maps and others include: political maps, foraging/herbal maps, treasure maps, magical features maps and more.
There are a variety of techniques when charting lands. Below is a short non-exhaustive list of methods.
For maps that cover a small area, for example individual lots of land, wooden stakes can be placed at regular intervals to form a grid-like pattern on the ground. By using the grid pattern, the cartographer can more accurately trace out features on paper with a similar grid on their page. Distances can be measured by counting paces, measuring with a rod, or lengths of string of a fixed distance.
The cartographer uses this supplementary technique to physically mark locations which will then be mapped. This could be in the form of marking trees with chalk or charcoal, using stakes, placing obvious rocks along a trail, burning a small patch of vegetation or a variety of other ways. Once landmarks are made obvious, it is easier for the cartographer to determine distances and a cardinal direction between these marked sites. This is particularly useful in landscapes that do not have distinct features, such as a forest, where one might otherwise get lost because it all looks the same.
Not all cartography needs to be out in the field. When there are existing maps of different areas or of different scales, a cartographer can combine them in such a way to create a more complete map, all with the same scale. This can also be done in reverse, where the cartographer takes a large map and creates a zoomed in portion that highlights a specific area. While all cartography incorporates the use of scale and geometry, desktop methods often require converting a map from one scale to another by making it bigger or smaller to fit with the other maps. When combining maps, it is important that there is at least one point of reference, preferably two, that both maps share so that they can be accurately combined.
Cardinal Mapping with Sightlines:
When there are obvious landmarks and good sightlines, the cartographer can stand at one landmark and use a compass to draw a line to the next landmark, matching the cardinal direction of the sightline. The distance between them can either be measured, or it can be confirmed by a second sightline from another known landmark to the one being charted. With a strong knowledge of geometry and angles, this effectively uses triangulation to determine the location of new landmarks, because where the sightlines cross on the page, is where the new landmark is located. Less skilled cartographers can also use this method, although their maps may be less accurate as a result since their sightlines may be more approximate.
This technique is usually paired with the above sightline technique because it uses sightlines and the concept of similar triangles. After calibrating a certain level focus, the cartographer can view a measuring rod held up at the location of the landmark and calculate the vertical distance from the bottom of the circular view to the top of the circle. Using this information, they can perform calculations to determine the associated distance from their viewing position to the landmark. Due to perspective and similar triangles, the closer the measuring rod is, the smaller the vertical distance will be when they view it through the fixed lens of the spy glass. The further away the measuring rod is, the larger the vertical distance would be seen on the measuring rod. This is an advanced technique and requires knowledge in mathematics.
For cartographers with the ability to fly, by their own means or a mount, or can reach a high vantage point, they can use their view from above to chart the landscape. While this has many obvious advantages and is great for preliminary maps there are a few drawbacks. Just as with any map, scale is important and due to the potential changes in elevation, the cartographer needs to be aware that if they are close to the ground the landscape features will appear much larger than if they are higher up. For small areas such as for city maps, this is less of an issue but for larger regional maps, the cartographer would need to identify reference points so that their maps maintain a consistent scale. Another drawback is the inability to see paths or roads through a forest, or even small rivers, as the trees can obscure the view. Lastly, aerial cartography often results in a limited understanding of elevations as they are less obvious from above and steep slopes will not impede passage as they would for a cartographer on foot.
Gathering Information from Locals:
While this technique is rarely used alone, it can help a cartographer start a new map or review an existing map for potential errors. Locals of a city or region usually know the landscape quite well and they can provide information on different locations or correct a map that may be inaccurate. The cartographer should always take such information with a grain of salt as there are always subconscious biases or inaccuracies on the part of locals.
Charting using Astronomy:
Cartographers can use the stars and other astronomical features to aid in their maps. Most commonly, astrological features are used to determine cardinal points when the cartographer does not have access to a good compass. For example, the suns rise and set at certain cardinal directions and there are constellations that a cartographer can use to determine which way is north. During travel across large distances such as sea travel, constellations can also be used to calculate distance in terms of lines of latitude. This is due to different constellations being visible depending on how far north or south the cartographer is situated (however this does not apply to lines of longitude). However, such calculations require in-depth knowledge of astronomy, navigation, and mathematics.
**Above astronomy technique needs review to fit with Idalos lore, preferably with input from Padraig.
Typical tools for charting and drawing maps include:
- Drawing implements and paper/parchment
The cartographer has just started learning to take the landscapes and features they see and put them on paper. Their maps have a large component of guesswork and are not always as methodical. As such, it is common for there to be at least one or two major inaccuracies in their map. Generally, they achieve better results when covering a smaller area for their map, such as a city or single lot of land. Their use of scale is sometimes questionable, the aesthetics of their maps are poor to moderate, and their maps are simplistic in how much detail is shown. In general, a basic map created by a novice cartographer would show about 5-10 features. Map ‘features’ include cities, mountain ranges, rivers, forests, coastline, roads, city blocks, houses, landmarks, borders, etc. As a rule of thumb, every element that is named is considered a feature as well as all major landscape elements.
The cartographer has now got the basics learned and they are able to better apply cartography techniques to create more accurate maps. Usually they are more methodical in their work and have different ways to check their map instead of relying on free-hand sketches. They still tend to have at least one major inaccuracy in their map but usually the map is functional enough to get a traveller to where they need to go. An average map created by a competent cartographer typically has 10-20 features shown. Sometimes competent cartographers can create specialized or themed maps however usually they exclusively stick to geographical features.
The expert cartographer can now start delving into more complicated techniques, particularly if they have experience in related skills such as mathematics or astronomy. The aesthetics of these maps is also greatly improved, especially when the cartographer is skilled in drawing or a related artistic field. Good maps usually have 20-50 features, and as such they can cover larger land areas without drastically reducing the amount of detail shown. It is also more common for the expert cartographer to create maps for a specific purpose or theme, depending on the client or need. At this level, the cartographer can use contour lines to depict elevation and rhumb lines for sea navigation.
The master cartographer not only makes highly detailed and accurate maps, but they are artistic as well as functional. Master quality maps can depict 50+ features and can cover an entire continent. Maps of this size and detail usually require a large roll of parchment or very fine writing to include all the elements of the map. The master cartographer uses many different techniques for charting maps as well as discovering new methods to chart lands. The world is truly at his fingertips.