Which grid system is used when the area is predominantly NS and involves projecting a horizontal slice of a cone with 90-degree transposition of the poles?

• A. British Grid
• B. Orthomorphic Grid
• C. Transverse Mercator Grid
• D. Military Grid (UTM)

Answer: (C)

When the area runs mostly north–south, you want a projection that minimizes distortion along those north–south lines. The Transverse Mercator projection achieves this by rotating the usual Mercator so the projection axis aligns with a meridian (a 90-degree shift from the standard arrangement). In this setup, the projection is most accurate along a north–south strip, which is exactly why a grid based on this system is used for long, slender regions and for zone-based grids like UTM. The idea of projecting onto a conical surface sliced horizontally and then rotating the poles fits this approach, yielding minimal distortion along the NS direction. That’s why the Transverse Mercator Grid is the best fit.