Which map projection has distances along the central meridian but distortions toward the east and west edges?

• A. Mercator projection
• B. Lambert Cylindrical projection
• C. Transverse Mercator
• D. Polyconic projection

Answer: (C)

The key idea is a projection that keeps distances true along a central line and let distortion grow away from that line. In the Transverse Mercator, the central meridian is the line of true scale (the scale factor is set so distances along that meridian are preserved). As you move east or west away from that central line, the projection’s scale changes and distances become distorted, producing distortions toward the edges. This behavior makes it the best fit for mapping a tall, north–south region by keeping accuracy along the central meridian while distortions increase toward the sides.

Other projections don’t exhibit this pattern. For example, the Mercator is conformal and preserves angles, but its distortion is driven by latitude (it enlarges distances as you move away from the equator) rather than by distance from a central meridian. The Lambert Cylindrical form spreads distortion primarily with latitude and has no single central line of true scale. The Polyconic has varying scale along different meridians without a single central meridian of true scale.