Map Projection

A map projection is a mathematical transformation that represents the curved Earth on a flat map. Because the sphere/ellipsoid cannot be flattened without distortion, projections preserve some properties at the expense of others: conformal (shape/angles), equal-area (area), equidistant (distance along lines), or azimuthal (direction from a point). Choices depend on map purpose and extent. For example, Web Mercator is conformal-ish at small scales but exaggerates areas toward the poles; Albers equal-area is favored for continental thematic maps; UTM is a set of conformal transverse Mercator zones for local accuracy. Understanding projection parameters—central meridian, standard parallels, false easting/northing, scale factor—is essential for aligning data. Bad projection handling produces offsets, broken topology, and wrong measurements. Provide explicit methods, QA notes, and version history so others can reuse the layer responsibly. Provide explicit methods, QA notes, and version history so others can reuse the layer responsibly. Provide a small distortion diagram on published products to signal trade-offs. Projecting graticules onto the map helps advanced users understand directional biases quickly.