Description

The aspect-adaptive cylindrical projection is a compromise map projection that adjusts the parallels to the height-to-width (aspect) ratio of an available canvas. It supports any ratio between 0.3 and 1.

This projection was developed by Bernhard Jenny, Bojan Šavrič, and Tom Patterson in 2014. It is available in ArcGIS Pro 2.1 and later, and ArcGIS Desktop 10.6 and later.

Projection properties

The subsections below describe the aspect-adaptive cylindrical projection properties.

Graticule

The aspect-adaptive projection is cylindric. All meridians and parallels are perpendicular straight lines. The meridians are equally spaced and the parallels are unequally spaced. The distribution of the parallels varies with the aspect ratio parameter. Both poles are presented as straight lines with the same length as the equator. The graticule is symmetric across the equator and the central meridian.

Distortion

This projection is neither conformal nor equal-area. Shapes, areas, distances, directions, and angles are all generally distorted. Equatorial areas are less distorted than areas in higher latitudes. At higher ratios, polar areas are largely exaggerated, but their shapes are closer to reality. At smaller ratios, polar areas are compressed north-south, but their areas are closer to correct proportions. The projection authors believe that aspect ratios between 0.55 (see the first image, above) and 0.7 (see the second image, above) are both a good compromise between acceptable areal deformations at high latitudes and overall pleasing appearance of landmasses.

Usage

This projection is primarily used for general world maps not requiring accurate areas. It supports the creation of a rectangle designed to fit a particular screen or page size. The authors suggest aspect ratios (rectangle height to width) between 0.55 and 0.7.

Limitations

This projection is supported on spheres only. For an ellipsoid, the semimajor axis is used for the radius.

Parameters

Aspect-adaptive cylindrical parameters are as follows:

• False Easting
• False Northing
• Central Meridian
• Aspect Ratio

The aspect ratio (rectangle height to width) must be between between 0.3 and 1. If you specify a ratio value outside the range, the projection algorithm uses a value in the limited range instead.

Particular parameter cases

When the aspect ratio parameter is set to 0.6, the resulting projection is the Compact Miller.

Sources

Jenny, B., Šavrič, B. and Patterson, T. (2015). "A compromise aspect-adaptive cylindrical projection for world maps." International Journal of Geographical Information Science, 29 (6), p. 935-952. DOI: 10.1080/13658816.2014.997734