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A geographic transformation converts coordinates between geodetic datums or reference frames, sometimes using grids and time-dependent parameters.
Without CRS metadata, GIS software can read coordinate values but cannot reliably know where they belong on the Earth or what their units mean.
A datum anchors coordinates to the Earth, a coordinate system defines how values are expressed, and a projection converts curved-earth positions to a plane.
Use Equal Earth for most area-based thematic world maps, Winkel Tripel for general reference, and a purpose-specific projection when routes, poles or interaction dominate.
Projection distortion is the change in area, angle, distance, direction or scale created when the curved Earth is represented on a plane.
Web Mercator enlarges area towards the poles because its scale increases with latitude in two dimensions.
Equal-area, conformal and equidistant projections preserve different geometric properties, and each promise has important limits.
Equal Earth is strongest for area-based world themes, Robinson and Winkel Tripel for balanced reference maps, and Web Mercator for standard tiled interaction.
A map projection is a mathematical method for representing locations on the curved Earth in a flat coordinate space.
Equal Earth is an equal-area projection for world maps that preserves the relative size of regions in a balanced, continuous form.