Projections

A map projection is a method of representing the curved surface of the Earth on a flat plane. Every projection distorts something — area, shape, distance, or direction — because no flat map can perfectly represent a sphere.

Graticule supports over 80 projections, grouped by family. You can search by name or browse the grouped list in the Projection selector in canvas panel of the lefthand sidebar.

Choosing a projection

For world maps, compromise projections like Natural Earth, Robinson, or Winkel Tripel are widely used and generally well-regarded. Equal Earth is a newer equal-area option.

For continental or regional maps, azimuthal or conic projections are usually appropriate. Albers USA is the standard for the US. Azimuthal Equal Area works well for polar regions and hemispheric views.

For country or sub-national maps, the right choice depends on the specific region. Many countries have an official or conventional projection — check before committing to one for a national-context map.

Projection families

Globe — renders the data on a rotatable sphere. Drag to spin.

Cylindrical — the simplest family. The globe is conceptually “unrolled” onto a cylinder. Mercator is the most familiar; it preserves shape but dramatically inflates area near the poles.

Pseudocylindrical — like cylindrical projections but with curved meridians, which reduces distortion. Most general-purpose world map projections fall here (Natural Earth, Robinson, Mollweide, Equal Earth).

Azimuthal — project onto a plane that touches the globe at a single point. The view radiates outward from that point. Good for polar views and hemispheric maps. In Graticule, azimuthal projections use drag-to-rotate interaction.

Conic — project onto a cone. Good for mid-latitude regions like North America, Europe, or China. Albers and Lambert Conformal Conic are the standards. Conic projections use drag-to-rotate interaction.

Interrupted — the globe is “interrupted” and unfolded with cuts, reducing distortion in specific regions at the cost of gaps in others.

Polyhedral — unfolds the globe onto a polyhedron. Waterman Butterfly is the most common example.

Coordinate systems and imported data

Graticule works in WGS84 (EPSG:4326) — longitude/latitude in decimal degrees. All data must be in this coordinate system to display correctly.

When you upload a file, Graticule inspects the coordinates. If they fall outside the valid WGS84 range, it warns you that the file is likely in a projected coordinate system (e.g. UTM or State Plane) and will not display correctly. To fix this, re-export the file as WGS84 from your GIS software before uploading.

Projection engine

Graticule uses D3-geo for all projection math. This covers the 80+ projections in the selector well, but it is not a full cartographic projection library. You will not find the deep parameter control or obscure local projections available in QGIS or ArcGIS. For highly specialized projection work, those tools are a better fit.