What is Distortion in Geography?
Every map you’ve ever seen is wrong—here’s why. Maps have helped, and continue to help, us navigate the world. They’re valuable tools to know where our next destination is, but in truth, they are generally flawed.
When we attempt to visualize the Earth’s curved surface and generate a two-dimensional representation, we are introduced to the concept of distortion. In this article, we examine the causes, types, and effects of distorting our understanding of geography and how drone technology aids in its comprehension.
What Is Distortion in Geography?
We describe distortions in geography as inaccuracies that occur when attempting to portray a three-dimensional surface, such as the Earth, on a two-dimensional map. It’s like peeling a circular fruit, such as an orange, and trying to smooth out its skin; you can still see its bumps and wrinkles, as well as the areas where you’ve peeled it, and it is a distortion in itself.
Mapmakers often use a projection to translate the Earth’s shape into easy-to-understand, flat maps. However, it should be noted that, while advantageous, a map projection cannot perfectly preserve all the three-dimensional geographic properties of the Earth, including its area, shape, and direction.
This idea is the central core of cartography, GIS, and the use of drones in mapping.
Why Is Understanding Map Distortion Important?
Our maps are not free from distortion. It’s in every flat map we own, affecting the way we see the world. An example of this is the size of Greenland and Africa. On a flat map, it may seem that Greenland has a larger landmass than Africa, but in reality, Africa is the larger continent.
Distortions as simple as the size of an area can shape our understanding of geography, our opinions on geopolitics, and our perception of the Earth. Schools have taught us little when discussing the concept of map distortion. Recognizing this phenomenon can improve our understanding of our geography. For land survey professionals, the use of GIS and drones in analyzing Earth’s surface is an avenue for more accurate spatial awareness and decision-making.
Why Is Distortion in Geography Important for Drone Pilots?
Geographic distortion is a critical factor in drone-based mapping, surveying, and geospatial analysis. When drones capture aerial imagery, the data can become distorted due to map projections, terrain variations, camera angles, lens limitations, and Earth’s curvature. If distortion is not properly understood or corrected, it can lead to inaccurate measurements, misaligned maps, and flawed decision-making.
For drone pilots working in industries such as land surveying, construction, agriculture, mining, and infrastructure inspection, even small distortions can result in costly errors. This makes it essential to understand how distortion occurs and how to minimize its impact through proper planning, calibration, and software correction.
How to Minimize Distortion in Drone Mapping
When minimizing distortion during drone mapping, a drone pilot must select an appropriate map projection. Drone mapping software simplifies this process by automating it, but manual alignment is still necessary to achieve accurate results.
Drones for Photogrammetry
Photogrammetry drones can capture an image and overlay different angles of it. This feature helps create a 3D model, especially of a specific area. Drones used for photogrammetry can capture images in aerial mode, which allows for capturing the width of areas. Terrestrial views can capture images from the ground up and are usually used in smaller and detailed geographies.
Photogrammetry drones capture an area by flying over it and capturing as many angles as possible, then stitching it together with photogrammetry software to create maps of large terrains and regions with utmost detail. Drones equipped with photogrammetry features are necessary for high-accuracy and large-scale mapping. They can capture even the most minor details and high-quality imaging of large areas.
Real-Time Kinematic (RTK) Systems
An RTK system provides a base with known coordinates and compares the drone’s data with the GPS data, allowing for real-time correction of the drone, which reduces errors at high altitudes or due to satellite issues. When using RTK systems, centimeter-level accuracy is achieved by utilizing the given map coordinates, thereby minimizing the effects of distortion.
This system corrects the errors caused by the ionosphere and troposphere, which create delays in Global Navigation Satellite System (GNSS) signals. RTK systems help in drastically reducing the need for physical Ground Control Points (GCPs), which are used for fine-tuning points in maps, as they are time-consuming to set up. For more accurate and less distorted mapping, the RTK system is the best feature for your drone, providing the precise geo-tagging data you need.
High-Resolution Imaging
When a drone features high-resolution imaging, it captures the finer details of the area being surveyed, and this is a particularly valuable feature when paired with photogrammetry drones. Aside from these features, here are some tips to find the correct map projection for your mapping needs:
Accuracy in Measures
If distance is crucial to your drone mapping needs, look for a model that features equidistant projection. Urban planning tasks, such as land-use analysis, require the accuracy of an area, which is critical. It is best to find a mapping drone that provides an equal-area projection.
Adaptable to Location Needs
Map projections like the Lambert Conformal work the best in regions near the equator. When dealing with drone mapping in those areas, look for drone mapping services that cater to those specific needs.
Integration of Geospatial Tools
Drones used for mapping should have GIS technology integrated, such as ArcGIS, so that the projection and data obtained for a specific location are accurate and in accordance with your analysis.
Types of Distortion and Map Projections
As discussed in this blog, we have learned that projecting Earth’s spherical shape onto a flat surface causes distortion; this is a fundamental concept when talking about map projections and their associated distortions. Map distortions are categorized based on the geometric property they distort the most. Four main classifications explain the distortions that occur in a 2D map:
- Area Distortion: This distortion affects the size of landforms. This misrepresentation can lead to inaccurate land measurements, invalidating data when drone surveying.
- Shape Distortion: The actual shape of an area has been distorted or changed. Distortion in shapes leads to errors in the estimation of surface area, which can affect industries that rely on it, such as the agriculture industry.
- Distance Distortion: Distance distortion refers to errors in measuring distance from one point to another, rather than representing the actual distance. For the aerial and maritime industries, this dramatically affects calculating route distances for drone operations.
- Direction Distortion: The compass direction from one area to another area on the map is askew. This distortion particularly affects maritime and aviation routes, resulting in inaccurate flight and sea paths.
Shape Projection
- Cylindrical Projection: This property presents the Earth’s surface onto a cylindrical shape. An example of this is the Mercator projection.
- Conic Projection: This property presents the Earth’s surface onto a conical shape. An example of this is the Lambert Conformal Conic projection.
- Azimuthal (One-directional) Projection: This property projects the Earth’s surface onto one flat geometric plane. An example of this is the Lambert Azimuthal Equal Area projection.
Property Preserved
- Conformal Projection: This map projection preserves the original shape of some areas while slightly distorting others.
- Equal-Area Projection: This map projection preserves the relative accuracy of area sizes but distorts shapes and directions.
- Equidistant Projection: This type of map projection preserves the relatively accurate distances between one area and all other areas on the map.
- Compromise Projection: This type of map projection attempts to reduce distortions on a map by distributing the relatively accurate information of area, shape, distance, and direction data across the map.
Common Map Projections in Geography
We have discussed the types of projections and distortions present in a flat-surface map. They are distinguished by the features they preserve or alter. Now, we differentiate map projections according to their commonalities and the names by which they are widely known.| Map Projection Name | Properties Preserved | Properties Altered |
|---|---|---|
| Mercator Projection | This map projection preserves the property of direction. | This map projection alters the shape of areas near poles or equators. |
| Robinson Projection | This map projection preserves all properties. | While it preserves features, it also distorts some properties. |
| Gall-Peters Projection | This map projection preserves the property of area. | This map projection distorts the property of shape. |
| Winkel Tripel Projection | This map projection minimizes all types of property distortion. | While this projection minimizes distortion, no property is perfectly preserved. |
| Lambert Conformal Projection | This map projection preserves the property of shape. | This map projection distorts the properties of area and distance. |
Real-World Examples and Industry Applications
When discussing map projection and distortion, it can’t be easily visualized by just an explanation. We will need real-life examples to understand the concept fully. Earlier in this blog, we discussed the distortion of Greenland and Africa on our world map, and we examined the Mercator projection, which preserves the property of direction but distorts the size of an area.
The Mercator projection inflates the area size of lands that are farther from the equator and near the poles, such as Greenland and Antarctica.
Their landmasses appear larger than continents and countries that are closer, a classic case of area distortion.
Industry-Specific Map Distortion Impacts
Aviation and Shipping
We have discussed in this blog how map distortions affect the planning of efficient routes in the air and maritime industries. When planning shipping routes, a close-to-accurate calculation of distances between islands is necessary. This planning is crucial for aerial and sea transportation, mainly used by the shipping industry.
When there is awareness of distortions on the map, it helps pilots and navigators plan their routes, taking into account the discrepancies and limitations caused by these distortions.
Agriculture
In agriculture, map projections are used to map out fields through farm mapping, helping farmers choose the most accurate projection to ensure better crop planning and an abundant harvest. Precision farming relies on advanced drone technology, remote sensing, GIS, and farm mapping tools to analyze soil health, crop growth, irrigation patterns, and field boundaries. Using the right drone features, such as high-resolution imaging and multispectral sensors, helps minimize distortion when interpreting agricultural maps. This enables farmers to make data-driven decisions, optimize resources, improve yield, and enhance overall farm productivity.
Mining and Energy
Surveying is a critical task in the mining and energy industries, as operations depend on having a clear and accurate understanding of the terrain before work begins. A precise representation of the land is essential to ensure safety, efficiency, and operational success. In these industries, land surveying must achieve the highest level of accuracy, with minimal to no distortion, since even small errors can impact mining processes, infrastructure planning, and the installation of energy towers. Accurate surveying helps reduce risks, improve decision-making, and streamline complex industrial operations.
City Planning and Development
For urban planning, maps are considered a crucial part of the job. Planners rely on maps to analyze the proper infrastructure and projects needed for the area’s development. Urban planners select appropriate drones and map projections for zoning planning and ordinances relevant to an area’s rules and regulations.
The Development and Progression of Map Distortion and Awareness
Mapmakers, or cartographers, as we call them, have always struggled with creating 2D maps due to the limitations associated with projections on the map The first map projection introduced was the Mercator projection. Its evolution began in 1959, when it became the standard projection for navigation maps. The downfall of this projection lies in the size of the landmasses it projects.
In today’s cartography industry, map projections have shifted to become more balanced and accurate. Examples of more balanced map projections are Robinson’s and Winkel Tripel’s. Modern mapping projections enable a more dynamic switching between projection and distortion analysis, thanks to emerging technologies like AI and GIS advancements that help reduce distortions, primarily when drones are used. These newer innovations have truly empowered the visualization of our Earth; we can now visualize and examine geographic data with exceptional accuracy.
Distortion in geography is inevitable, but it is also manageable. Being aware of map distortion enables people to interpret maps with greater caution, choosing a suitable projection and thereby improving spatial accuracy. Whether you’re an academic, researcher, or drone pilot, understanding map distortion is key to understanding geography.
Drone as a Service (DaaS) specializes in drone mapping solutions that minimize distortion effects through the use of advanced technologies, including photogrammetry and thermal imaging. Our tools are equipped with high-resolution imaging and drones that can fly long distances for distortion-free and durable outputs.
CTA Button: Want to learn more about photogrammetry drones and high-resolution drone mapping? Contact Drone as a Service (DaaS) and book a demo today!
FAQS
What is distortion in geography?
Distortion in geography refers to inaccuracies in Earth’s shape, size, area, distance, or direction when its spherical surface is represented on a flat map.
Why does distortion occur in maps?
Distortion occurs because the Earth is a sphere, and no flat surface can perfectly represent a curved shape without altering some geographic properties.
What are the four main types of distortion in geography?
The four main types of distortion affect area, size (shape), direction, and distance on maps.
Which map projection is most accurate?
For flat maps, the Winkel Tripel projection is considered one of the most accurate because it balances and minimizes multiple types of distortion.
Can we make a distortion-free map?
No, we cannot make distortion-free maps. Flat maps always distort geographic properties. Only globes can preserve Earth’s actual area, shape, direction, and distance.
Why does Greenland look bigger than Africa on some maps?
The Mercator projection exaggerates regions closer to the poles, such as Greenland, making them appear larger than Africa on a flat map.
How do map projections balance different types of distortion?
Each projection prioritizes certain properties. For example, the Gall-Peters projection preserves area, while the Mercator projection preserves direction.
Can technology like 3D mapping reduce distortion?
Yes, 3D mapping technologies reduce distortion by representing geographic features more realistically while preserving spatial properties in three dimensions.
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