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A Guide to Map Symbols

Understanding Map Symbols and Their Significance

Introduction to Map Symbols

Map symbols are the visual tools used in cartography to represent real-world features on a map. These symbols, ranging from simple dots to intricate icons, serve as a bridge between the physical world and its graphical representation. They play a pivotal role in conveying information, ensuring that maps are not just accurate but also intuitive and informative. Whether it’s a tree icon indicating a forest or a red line denoting a highway, map symbols provide a quick and clear understanding of the terrain and features, making maps an essential tool for navigation, planning, and understanding our world.

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Historical Context of Map Symbols

The use of symbols to represent the world around us dates back to ancient civilizations. From the rudimentary drawings on cave walls to the intricate maps of Babylon, symbols have always been a cornerstone of human understanding of space and geography. In ancient times, cartographers relied on firsthand experiences, travelers’ tales, and sometimes even myths to depict lands, seas, and landmarks. These early maps often used basic symbols, with a heavy reliance on natural colors and simple shapes.

As civilizations advanced, so did the art of map-making. The Renaissance period, for instance, saw a surge in exploration and, consequently, a need for more accurate maps. Symbols became more standardized, and legends became a common feature, helping users decode the map’s information.

The transition from hand-drawn to digital cartography in the 20th and 21st centuries marked a significant evolution in map symbols. Digital tools allowed for greater precision, consistency, and the ability to represent complex data layers. Today, with the advent of Geographic Information Systems (GIS) and satellite imagery, map symbols have become more sophisticated, catering to a wide range of applications from urban planning to environmental conservation.

Understanding Map Symbols

Map symbols serve as the language of cartography, enabling a diverse audience to interpret and understand the geographical information presented. These symbols are more than just visual markers; they encapsulate a range of purposes:

  • Declaring Existence: At their core, symbols indicate the presence of geographical phenomena, whether it’s a mountain, river, city, or any other feature.
  • Showing Location and Extent: Symbols pinpoint the exact location of a feature and can also illustrate its size or extent. For instance, a larger circle might indicate a bigger city, while a longer line could represent a longer river.
  • Visualizing Attributes: Beyond just location, symbols can convey additional information about a feature. For example, color variations might indicate different temperatures in a weather map or different elevations in a topographical map.
  • Aesthetic Appeal: A well-designed map is not only informative but also visually pleasing. Symbols contribute to the map’s aesthetics, ensuring that it is engaging and easy to read.
  • Establishing Visual Hierarchy: Not all information on a map holds equal importance. Through varying sizes, colors, and boldness, symbols help establish a visual hierarchy, guiding the viewer’s attention to the most crucial details first.

Map symbols can be categorized based on their representation. While some symbols, like buildings or roads, represent tangible objects, others might represent intangible masses such as air quality or temperature. This distinction ensures that a map provides a holistic view of the area it represents, combining both concrete and abstract information.

Types of Map Symbols

Map symbols, in their diversity, can be categorized based on their visual representation and the manner in which they connect the graphic on the map to the real-world feature. Here’s a deeper dive into the various types:

  • Iconic Symbols: These are symbols that bear a direct resemblance to the real-world feature they represent. For instance, a tree icon might be used to indicate a forest or wooded area, and a fish symbol might denote a fishing zone.
  • Functional Symbols: These symbols represent the activity or function of a particular feature. A skier icon, for instance, might indicate a ski resort, while a plane symbol could represent an airport.
  • Conceptual Symbols: These symbols represent an idea or concept related to the feature rather than the feature itself. An example would be a dollar sign used to indicate an area of economic activity or wealth.
  • Conventional Symbols: These are symbols that have been universally accepted and understood due to long-standing conventions. For example, a red line often represents a major highway, and blue lines typically indicate rivers or streams.
  • Ad Hoc Symbols: These are symbols created specifically for a particular map or project. They might not have an intuitive connection to the feature they represent and usually require a legend for interpretation. For instance, a unique color code might be used to represent different demographic groups in a population density map.

The different types of map symbols is crucial for both map creators and users. While map creators need to choose symbols that accurately and effectively convey information, users must be able to interpret these symbols correctly to glean insights from the map.

Dimensionality in Map Symbols

The spatial representation of geographical features on a map is often determined by their inherent dimensionality. This dimensionality plays a pivotal role in how these features are symbolized. Let’s explore the various spatial dimensions and how they influence map symbols:

  • Point Symbols: Representing zero-dimensional features, point symbols are used for geographical entities that can be depicted as a single point on a map. Examples include landmarks like monuments, locations of specific events, or the position of a city when the map scale doesn’t allow for a more detailed representation.
  • Line Symbols: These symbols represent one-dimensional features and are used for linear entities like roads, rivers, and railway tracks. The thickness, color, and style of the line can convey additional information, such as the type of road (highway vs. local street) or the size of a river.
  • Planar Region Symbols: Representing two-dimensional features, these symbols are used for areas like lakes, forests, or urban regions. They can be depicted using various colors, patterns, or textures to indicate different types of regions or their attributes.
  • Volumetric Region Symbols: While less common, these symbols represent three-dimensional spaces, such as the volume of air traffic over an area or the distribution of marine life at different depths in a body of water. They might be represented using 3D graphics or layers of shading.
  • Cartographic Generalization: An essential concept in map-making, cartographic generalization refers to the simplification of features. Due to scale constraints, not every detail can be included in a map. For instance, a small pond might be omitted from a national map but included in a local city map. Similarly, a winding road might be represented as a straight line in a smaller-scale map. This generalization can sometimes lead to discrepancies in how dimensionality is represented.

The dimensionality of map symbols is crucial for accurate interpretation. It ensures that users can differentiate between types of features and understand the spatial relationships between them, providing a clearer picture of the geographical landscape.

Level of Measurement in Map Symbols

Map symbols do more than just pinpoint locations; they also convey attributes or properties of geographical phenomena. The level of measurement dictates how these attributes are represented and interpreted. Here’s a breakdown of the various levels and their implications for map symbols:

  • Nominal Measurement: This level deals with categorical data where no specific order is implied. For instance, different colors might be used to represent different types of land use, such as residential, commercial, or agricultural.
  • Hierarchical Measurement: This involves a clear hierarchy or order but without consistent intervals. An example might be a map showing administrative divisions, from countries to states to cities.
  • Ordinal Measurement: Here, the order matters, and there are clear distinctions between categories. For instance, a soil quality map might use symbols to rank areas from poor to excellent.
  • Interval Measurement: This level deals with data where there’s a consistent interval between values but no true zero point. Temperature maps often use this level, with colors representing temperature ranges.
  • Ratio Measurement: Similar to interval measurement, but with a true zero point. Elevation or altitude maps often use this level, with symbols indicating height above sea level.
  • Cyclical Measurement: This involves data that operates in cycles. A common example is a map showing phases of the moon or tidal patterns.
  • Amount/Count Measurement: This level represents sheer quantities or counts. For instance, a map might use varying sizes of circles to indicate the number of people in different cities.

Understanding the level of measurement is crucial for both the mapmaker and the user. It ensures that the right type of symbol is chosen to represent data accurately and that users can interpret the map correctly, drawing meaningful conclusions from the represented data.

Cognition and Semiotics in Map Symbols

The effectiveness of map symbols hinges not just on their design but also on the cognitive processes they trigger and the semiotic principles they embody. Delving into these aspects:

  • Cognitive Principles in Cartography:
  • Recognition: Effective map symbols are easily recognizable, allowing users to quickly identify features without referring to a legend frequently.
  • Differentiation: Symbols should be distinct enough to differentiate between various features, avoiding confusion.
  • Memory Retention: Well-designed symbols are memorable, aiding users in recalling map information even after a single glance.
  • Consistency: Using consistent symbols across different maps or sections of a map ensures a smoother user experience.
  • Semiotics and Map Symbols:
  • Sign, Signifier, and Signified: In semiotic theory, a ‘sign’ is a combination of its physical form (the ‘signifier’) and the concept it represents (the ‘signified’). In cartography, the map symbol is the signifier, and the real-world feature it represents is the signified.
  • Symbolic Connotations: Some symbols carry cultural or societal connotations. For instance, certain colors or shapes might have specific meanings in different cultures, influencing their interpretation on a map.
  • Arbitrariness and Convention: While some symbols have a natural association with their meanings (like a tree symbol for a forest), others are arbitrary and are understood through convention (like a blue line for a river).
  • Challenges in Cognition and Semiotics:
  • Cultural Variations: Symbols that are easily understood in one culture might be confusing or misleading in another.
  • Overloading Information: Striking a balance between providing sufficient information and overwhelming the user is crucial. Too many symbols or overly complex symbols can make a map difficult to interpret.

Understanding the cognitive and semiotic aspects of map symbols is essential for effective cartographic communication. It ensures that maps are not only visually appealing but also intuitively comprehensible, bridging the gap between graphical representation and real-world understanding.

Visual Variables in Map Symbols

The effectiveness of a map symbol is often determined by its visual variables. These variables, as proposed by the French cartographer Jacques Bertin, play a pivotal role in how information is conveyed and interpreted on a map. Here’s an exploration of these visual variables:

  • Position: The most fundamental of all variables, it determines the exact location of a feature on a map. Changing the position of a symbol can change the entire meaning of a map.
  • Size: This variable can indicate the magnitude or importance of a feature. Larger symbols might represent more significant or populous cities, while smaller symbols could indicate towns or villages.
  • Shape: Different shapes can be used to represent different categories or types of features. For instance, squares might represent cities, while triangles could indicate mountain peaks.
  • Value: Refers to the lightness or darkness of a symbol. This can be used to represent a range, such as elevation, with lighter values indicating lower elevations and darker values higher elevations.
  • Color: One of the most impactful variables, color can convey a variety of information. Warm colors might indicate higher temperatures on a weather map, while cool colors indicate cooler temperatures.
  • Orientation: The direction a symbol faces can convey information. For instance, the orientation of wind barbs on a weather map indicates wind direction.
  • Texture/Grain: Patterns or textures can differentiate between areas or features. A striped pattern might represent a certain type of land use, while a dotted pattern could indicate another.
  • Transparency/Opacity: In modern digital cartography, the transparency of a symbol can convey depth or importance. A more transparent symbol might indicate a less significant feature, while a fully opaque symbol represents a primary feature.

Visual Hierarchy in Map Symbols

Visual hierarchy is a foundational principle in design, and cartography is no exception. It refers to the arrangement and presentation of symbols in a way that guides the viewer’s attention, emphasizing certain elements while de-emphasizing others. Here’s a closer look at the role of visual hierarchy in map symbols:

Importance of Hierarchy:

Guiding Attention: A well-established hierarchy ensures that the most critical information catches the viewer’s eye first, followed by secondary and tertiary details.

Reducing Clutter: By prioritizing certain symbols over others, cartographers can prevent maps from becoming too cluttered or overwhelming.

Techniques to Establish Hierarchy:

Size Variation: Larger symbols naturally draw more attention than smaller ones. For instance, capital cities might be represented with larger dots compared to smaller towns.

Color Contrast: Bright or contrasting colors stand out more than muted or similar hues. A brightly colored region might indicate an area of particular interest or significance.

Symbol Complexity: More detailed or intricate symbols can be used for features of higher importance, while simpler symbols represent less critical features.

Layering and Opacity: In digital maps, layers can be used to establish hierarchy. Features on upper layers overshadow those on lower layers. Adjusting the opacity of symbols can also indicate their relative importance.

Challenges in Establishing Hierarchy:

Balancing Detail and Simplicity: While it’s essential to highlight crucial features, it’s equally important to ensure the map remains readable and not overly complex.

Cultural and Regional Differences: What’s considered important in one culture or region might differ in another, affecting the perceived hierarchy.

Feedback and Iteration: Establishing an effective visual hierarchy often requires feedback from users and multiple iterations. Cartographers must be open to adjusting their designs based on user experience and comprehension.

The Map Legend: Decoding Symbols

The map legend, often situated in a corner or side of a map, serves as the key to unlocking the map’s language. It provides context and clarity, ensuring that the symbols used are easily understood by the viewer. Here’s an exploration of the importance and intricacies of the map legend:

Role of the Legend:

Clarification: The legend demystifies symbols, especially ad hoc or unconventional ones, ensuring that viewers don’t misinterpret the map.

Standardization: For maps that are part of a series or for organizations that produce multiple maps, legends ensure consistency across all representations.

Components of a Legend:

Symbols and Icons: A direct representation of the symbols used on the map, accompanied by their meanings.

Color Codes: If colors are used to represent different categories or gradients, the legend will provide a clear breakdown.

Scale: Often, legends will include a scale to indicate distances, especially if the map doesn’t have a grid.

Designing an Effective Legend:

Simplicity: Legends should be straightforward and easy to understand. Overloading a legend with too much information can be counterproductive.

Hierarchy: Just as maps have a visual hierarchy, legends too should prioritize information, presenting the most crucial symbols prominently.

Accessibility: Legends should be designed keeping in mind color blindness and other visual impairments. Using patterns in addition to colors or choosing color palettes that are distinguishable by all can be beneficial.

Challenges in Legend Creation:

Space Constraints: Especially in detailed maps, finding space for a comprehensive legend can be challenging.

Dynamic Maps: For digital maps that change based on user input or real-time data, creating a static legend can be challenging.

The Evolving Nature of Legends:

With the rise of interactive digital maps, legends too have evolved. They can now be dynamic, changing based on what part of the map is being viewed, or can be interactive, allowing users to click on parts of the legend to see only specific categories on the map.

While map symbols are the language of cartography, the legend is the dictionary that makes this language accessible to all. An effective legend ensures that a map’s information is transparent, comprehensive, and universally understood.


Map symbols, in their myriad forms and functions, are the lifeblood of cartography. They transform raw geographical data into visual stories, making maps not just tools of navigation but also narratives of our world. From the ancient mariner’s hand-drawn maps to today’s sophisticated digital cartography, symbols have been the constant, guiding us through unknown terrains and helping us make sense of our surroundings.

The art of map-making lies in choosing the right symbols – ones that are intuitive, informative, and aesthetically pleasing. But it’s also a science, rooted in cognitive psychology, semiotics, and design principles. It’s a delicate balance between representing reality and simplifying it, between being comprehensive and being comprehensible.

As we move into an era of augmented reality, AI-driven insights, and real-time data visualization, map symbols will continue to evolve. But their core purpose will remain unchanged: to bridge the gap between the physical world and its graphical representation, making the complex simple and the distant near.

About the Author
I'm Daniel O'Donohue, the voice and creator behind The MapScaping Podcast ( A podcast for the geospatial community ). With a professional background as a geospatial specialist, I've spent years harnessing the power of spatial to unravel the complexities of our world, one layer at a time.