Oct 7
What are Isometric, Choropleth, Chorochromatic and Isopleth Maps?
- Işık Arda Yardımsever
- Oct 7
- 5 min read
Maps aren't just for navigation; they're also a powerful way to visualize information. Especially when it comes to thematic maps, as different types of maps make a wide range of data, from landforms and population distribution to climate and geological structure, more understandable. We know that thematic maps provide data-based visualization, but how well do we understand thematic map types? In this article, we'll briefly explain what isometric, choropleth, chorochromatic, and isopleth maps are, what they do, and why they're used.
Contents
Quick Isometric, Choropleth, Chorochromatic and Isopleth Map Comparison
An isometric map shows elevation or depth using contour lines. It presents a three-dimensional view of terrain on a two-dimensional plane.
A choropleth map colors predefined areas, such as countries, regions, or states, based on statistical data. This method emphasizes the distribution across areas, rather than the variation within areas.
A chorochromatic map divides an area into homogeneous regions based on categorical variables such as soil type or vegetation. It does not use gradations; it emphasizes qualitative differences.
An isopleth map connects points of equal value with lines (isopleths). It's ideal for displaying continuous variables like temperature, precipitation, or air pollution. These maps clearly visualize smooth transitions in data.
Thematic map types briefly show:
Isometric maps: Show physical height and depth.
Choropleth maps: Show the regional distribution of statistical data.
Chorochromatic maps: Perform qualitative classification by distinguishing categories.
Isophlete maps: Reveal spatial gradients by displaying continuous variables as isolines.
Now let's move on to the details of these maps.
What is an Isometric Map?
An isometric map , or contour map, shows elevation differences on the Earth's surface. On this map, points at the same level are connected by curved lines, called contour lines . For example, the curves corresponding to points at the summits and foothills of mountains are shown with different colors or symbols. By looking at these curves, map readers can identify the location of hills, valleys, and ridges. Close proximity of curves on a map indicates a steep slope in that area, while sparseness indicates a low slope.
What is the use of an isometric map?
Isometric maps are used in geography, geology, and engineering to understand ground features. While they don't provide elevation information in a measured manner, they do reveal landforms at a glance. For example, when planning roads or buildings, tightly spaced lines on an isometric map indicate steep slopes, while wide intervals indicate plains. Most topographic maps are also prepared using this method; the term "isohypnos map" in topography refers to maps with contour lines.
Why Use Isometric Maps?
Isometric maps are preferred because they allow for a clear representation of three-dimensional terrain on two-dimensional paper. Because they depict real mountains, valleys, and ridges as if they were drawn on a map, map readers can more easily visualize high and low elevations. This simplifies comparisons of which areas on the map exhibit greater and lesser elevation changes.
What is a Choropleth Map?
A choropleth map displays the distribution of a specific data type, such as population, income, or education level, across geographic regions using colors. Each region on the map is filled with a color or shade representing the value associated with that region. For example, on a population density map, densely populated areas are colored darker, while sparsely populated areas are colored lighter.
What is the Use of a Choropleth Map?
Choropleth maps are often used to visualize the regional distribution of numerical data. For example, data such as population, literacy rate, and income levels are collected by province or country, and each region is colored accordingly. This allows anyone viewing the map to quickly identify which regions have higher and lower values by looking at the color tones. For example, on a choropleth map showing population density in a country, darker areas represent higher population density.
Why is a Choropleth Map Used?
Choropleth maps make it easier for policymakers or researchers to compare which regions have higher or lower values. For example, for emergency planning, these maps can quickly identify which provinces are densely populated. Their colorful appearance makes information transfer more intuitive because the differences between data are striking.
What is a Chorochromatic Map?
A chorochromatic map is a special type of thematic map where categorical data is represented by colors. "Choro-" refers to region, and "chromatic" refers to color. In these maps, areas on the map surface are colored differently depending on their category. For example, on a geological map, different rock types are represented by distinct colors representing each type. Or on a climate map, ecosystems such as rainforests, deserts, and tundra are represented by distinct colors for each type. This allows qualitatively distinct regions on the map to be immediately recognized.
What is the Use of a Chorochromatic Map?
A chorochromatic map allows you to visualize multiple categories or layers simultaneously. In Geographic Information Systems, it can present different data such as slope, elevation, and temperature in layers of color. For example, on a terrain map, both soil types and vegetation types can be marked with different colors. Information such as rock types on geological maps, activity areas on economic maps, or spoken language regions on language maps can be differentiated by color.
Why is a Chorochromatic Map Used?
Chorochromatic maps are used because they simplify complex, multi-layered information using color. Even the smallest categories can be easily distinguished thanks to the hue and saturation of colors. For example, if different geological layers or soil types overlap in the same area, each highlighted in a different color allows for clear, uninterrupted information. Therefore, detailed comparisons can be made at a glance, as each color on the map corresponds to a different category.
What is an Isophlet Map?
An isopleth map , isohypse map, or isoline map is a map created by connecting points of equivalent value based on numerical data with lines. For example, on weather maps, lines passing through points of equivalent value for continuous variables such as temperature or pressure are called isotherms or isobars. On an isopleth map, points of the same value are connected by a line. Thus, each isopleth on the map represents a specific numerical value.
What is the Use of an Isopleth Map?
Isophlet maps are commonly used in fields such as atmospheric science, meteorology, and hydrography. These maps display continuously changing values such as temperature distribution, precipitation, air pressure, sea level pressure, or soil moisture. For example, on a temperature map, all points equal to 20°C are drawn by connecting them. Similarly, lines can be drawn for different precipitation values and painted on the map.
Why is an isopleth map used?
Isophlet maps are used to visualize the continuous distribution of data and clearly reveal equivalent levels on the map. Lines of equal value within the data are displayed in the same color or style, making it immediately clear where measurements are equal. High and low value areas can be compared by examining the range of lines with varying values. This method allows for easy reading of variables such as temperature or pressure on the map, as it displays intermediate values gradually rather than sharply defined boundaries.
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