The story of Plate carrée · Ancient roots
Plate carrée
An old grid finds a new job in digital imagery.
Explore Plate carrée →The stronger line marks the equator.
Why this map exists
An old grid finds a new job in digital imagery.
Place longitude and latitude on a simple, evenly spaced grid. In the Plate carrée form, the equator is the standard parallel and the full world has a 2:1 rectangular outline.
How the idea developed
Antiquity
An attribution, not a precise birthday
Ptolemy credited Marinus of Tyre with an equidistant cylindrical approach around AD 100. Snyder also discusses a possible earlier origin with Eratosthenes. The attribution belongs to the broader projection family, so a single certain invention date would be misleading.
Snyder · USGS Bulletin 1532, equidistant cylindrical historyThe equatorial form
A square grid of coordinates
Setting the standard parallel to the equator produces Plate carrée. Equal angular increments in longitude and latitude then have equal spacing on the map. Other equirectangular forms use different standard parallels.
PROJ · Equidistant cylindricalDigital imagery
Simple coordinates, useful pixels
A regular grid makes the relationship between an image pixel and its geographic coordinates straightforward. Global raster datasets use this convenience even though the displayed map stretches polar regions.
PROJ · Equidistant cylindrical
What you gain. What changes.
What stays true
North–south distances along meridians at a constant scale, and east–west scale along the equator in the classic orientation.
What changes
East–west stretching increases toward the poles. Neither relative areas nor local angles are generally preserved.
Projection properties: PROJ · Equidistant cylindrical
A common misunderstanding
“Equidistant” does not mean all distances between all places are correct. Also, Plate carrée is a particular equirectangular form; the ancient history of the family is not proof that its exact modern form was invented on a known date.
What changes in a country-centered view?
These historical descriptions refer to the classic orientation. MapStudy can rotate the projection’s reference frame so the place facing you becomes the center. The projection still preserves its defining property, but references to the equator, poles, and navigation do not transfer unchanged to the rotated view. Geographic latitude and longitude lines may curve.
The unfolding animation illustrates a mathematical transition. The intermediate shapes are not separate named projections, and Earth is not physically peeled into this map.
See the idea for yourself
What changes when your country becomes the center?
- Open the centered Plate carrée view, then choose a country using the search below the map.
- Unfold Earth. Follow the geographic latitude and longitude lines as they curve in this rotated view.
- Choose “Classic orientation” to see the familiar straight geographic grid.
Opens in another tab so you can keep the steps nearby.
Sources & further reading
The history and explanations are original MapStudy writing based on the references linked above. Uncertain origins are identified as such. We credit the projection’s creators and later advocates; MapStudy’s contribution is this interactive learning experience.
- PROJ · Equidistant cylindrical · mathematical reference
- Wikipedia · Equirectangular projection · further reading
Our diagrams use the same spherical equations as the explorer. They show geographic grids, not historical source material.