Question

Describe the general properties of the following projections: Universe Transverse Mercator (UTM), State plane system, and Robinson projection.

Short answer

UTM minimizes distortion within zones, SPCS is state-specific with minimal distortion, and Robinson is visually appealing for the entire world with balanced distortions.

Step-by-step solution

- Understanding UTM Projection

The Transverse Mercator Projection (UTM) is a cylindrical map projection. It divides the Earth into 60 zones, each 6 degrees of longitude wide. It is used for large-scale mapping, typically with minimal distortion in shape and distance within each zone. However, distortion increases as you move away from the central meridian of each zone.

- Understanding State Plane Coordinate System (SPCS)

The State Plane Coordinate System (SPCS) is a set of 124 geographic zones or coordinate systems uniquely designed for specific regions in the U.S. Each state may have multiple zones. This system ensures minimal distortion over small areas by using either Transverse Mercator or Lambert Conformal Conic projections, depending on the state’s extents and shape.

- Understanding Robinson Projection

The Robinson Projection is a compromise map projection that shows the entire world at once. It is neither entirely conformal nor equal-area. Instead, it balances size and shape distortions, making it visually appealing for world maps. This projection is often used for educational and thematic maps, focusing on a more practical visual representation rather than precision.

- Summarizing Projection Properties

UTM is best for localized areas with minimal distortion within zones but higher distortion outside them. SPCS reduces distortion for specific areas in the U.S., tailored by the state. The Robinson projection offers a balanced, aesthetically pleasing world view with some distortion in size and shape globally but is suitable for general representations.

Key concepts

Transverse Mercator Projection

The Transverse Mercator Projection (UTM) is used for detailed, large-scale mapping. How does this cylindrical map projection work? It divides the Earth into 60 zones. Each zone is 6 degrees of longitude wide. Within each zone, distortion in shape and distance is minimal, making it highly accurate. However, as you move away from the central meridian of each zone, distortion increases. This means it’s excellent for mapping smaller, localized areas but less effective for mapping larger regions.

State Plane Coordinate System

The State Plane Coordinate System (SPCS) is specifically designed for the United States.
This system divides the country into 124 zones, each tailored to minimize distortion for its region.
Each state can have multiple zones, depending on its size and shape.

• Projections Used: The Transverse Mercator and Lambert Conformal Conic projections are utilized based on the state’s requirements.
• Accuracy: By using these projections, SPCS ensures very low distortion for small areas, which is perfect for engineering and surveying tasks.

It’s essentially a customized way to map each part of the U.S. with high precision.

Robinson Projection

The Robinson Projection is famous for showing the entire world in a way that looks appealing.
Unlike some other projections, it doesn’t perfectly maintain shape or size but offers a balanced view. This makes it great for educational maps and thematic displays. Here’s why it stands out:

• Compromise Projection: It balances distortions in both size and shape instead of eliminating one completely.
• Visual Appeal: It’s specifically designed to be pleasing to the eye, making it popular for world maps meant to give a general overview rather than precise measurements.

Despite some distortion, it’s practical and functional for most world mapping purposes.