Plate Carrée projection calculator

Longitude becomes the horizontal x coordinate, and latitude becomes the vertical y coordinate. This direct equidistant cylindrical mapping is useful for learning, lightweight data preparation, gridded geographic datasets, and systems that explicitly expect unscaled longitude and latitude on a rectangular plane. The result clearly identifies both the projection and its degree-based units.

Understand what the Plate Carrée projection returns

Plate Carrée is the simplest equidistant cylindrical projection. It places longitude on the horizontal axis and latitude on the vertical axis, with both axes expressed in degrees. For an input at longitude -73.9857 and latitude 40.7484, the projected point is therefore x = -73.9857 and y = 40.7484. No scale factor, false easting, false northing, ellipsoid, or central-meridian offset is introduced by this calculator. That direct relationship makes the output easy to inspect and easy to reverse: longitude is recovered from x, while latitude is recovered from y. The simplicity does not mean the plane represents physical distances uniformly. One degree of longitude covers less ground as a point approaches either pole, even though the x spacing remains constant on the map. Use these results when a workflow calls specifically for Plate Carrée coordinates in angular plane units, not when it requires metres, local engineering coordinates, or a conformal display. The returned projection and units fields make that assumption explicit for downstream software.

Enter and interpret the coordinate correctly

Provide latitude and longitude as finite decimal numbers. Latitude must lie from -90 through 90 degrees, and longitude must lie from -180 through 180 degrees. Positive latitude is north of the equator, negative latitude is south, positive longitude is east of the prime meridian, and negative longitude is west. The calculator keeps that sign convention unchanged. The output x value is exactly the accepted longitude, and the output y value is exactly the accepted latitude. This order matters because geographic data is often written as latitude followed by longitude, while planar geometry is conventionally written as x followed by y. The named fields remove that ambiguity. Inputs may also use the descriptive aliases latitude and longitude, although lat and lon are the canonical API fields. Values outside the stated geographic ranges are rejected rather than wrapped or clipped, because silent normalization could conceal a swapped coordinate or a source-data error. Decimal precision is preserved as JavaScript numeric precision permits; the tool does not round a valid input or claim additional accuracy.

Choose Plate Carrée for the right workflow

This projection is a practical fit for global raster grids indexed directly by longitude and latitude, simple teaching diagrams, coordinate sanity checks, and interchange formats whose documentation explicitly defines x as longitude and y as latitude. It is also convenient for quick plots where preserving the original angular values is more important than preserving shapes, areas, or ground distances. Its limitations should guide the decision. Plate Carrée stretches features horizontally toward the poles, does not preserve area, and does not preserve local shape away from the equator. A straight-line distance measured between its x and y values is a distance in degrees, not a reliable surface distance in kilometres or miles. Web maps commonly use Web Mercator instead, while analysis may require an equal-area projection or an appropriate local coordinate reference system. This calculator intentionally performs only the direct Plate Carrée mapping, so it does not infer a datum or transform between datums. Confirm that incoming coordinates already use the geographic reference expected by the consuming application before treating the planar result as interoperable map data.