What is Map Overlay?
Map overlay is a technique used in cartography and Geographic Information Systems (GIS) that allows us to layer two or more maps to examine and analyze spatial relationships. To put it simply, it's like placing a tracing paper on a sketch
to compare or combine elements.
The True Size Of - A Key Concept
The concept of the 'true size of' geographical areas is a crucial aspect in map overlay. Due to the nature of mapping a
3D surface (the Earth) onto a 2D plane (the map), sizes can be distorted, especially in conventional map projections
like the Mercator. For example, Africa looks much smaller on such maps, despite being larger than Greenland. Map overlay
allows us to view the 'true size of' these regions by comparing them directly.
Uses and Applications of Map Overlay
Map overlay isn't just an academic exercise. It has a wide range of practical applications. It aids in urban planning,
helping city officials align resources like utilities and public services. Ecologists use map overlays to study natural
phenomena and their impact on different regions. Moreover, it's commonly used in navigation and Traffic Management , and even in Environmental Monitoring such as climate change studies to visualize the potential impact of rising sea levels on different parts of the world.
How Map Overlay Works
The process of map overlay involves taking two or more maps with different types of Geospatial Data , and aligning them based on common geographical coordinates. This can be achieved manually, but today it's often done using GIS software. Once the
maps are overlaid, one can see how different geographical features or data sets interact. For instance, overlaying a
rainfall map with a population density map could show how heavy rains might affect populated areas.
Conclusion
In conclusion, map overlay is a powerful tool for understanding the world around us. By allowing us to see the 'true
size of' geographical areas and how different aspects of the world interact, it provides invaluable insights for
scientists, planners, and anyone with an interest in understanding our planet.