A Mercator chart is classified as a cylindrical projection. This type of projection is created by projecting the surface of the Earth onto a cylinder that tangentially touches the Equator. The key characteristic of the Mercator projection is that it maintains accurate angles, making it particularly useful for navigation, as it allows for straight lines to represent constant compass bearings. This is why sailors have traditionally favored the Mercator projection for maritime navigation. However, it distorts size and area, particularly at higher latitudes, making land masses appear larger than they are relative to those near the equator.
The other options describe different types of projections that do not align with the properties of the Mercator chart. Simple conic projections and polyconic projections utilize different methods of projection to represent the Earth’s surface and are often more suitable for regions that are elongated east-west or west-east. Rectangular projection is not specifically a standard category in terms of map projections as it could refer more generally to any map created on a rectangular grid. Thus, the classification of a Mercator chart as a cylindrical projection is accurate and highlights its unique navigational advantages.