Geographical Projections

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This document explains why map projections are important to geographic maps. It also lists their supported types, and details how to create specialized projections in the map control.

Overview

There are numerous ways to depict the Earth's surface on a map. Depending on the selection, the surface can be drawn as a circle, a rectangle, an oval, etc.

Map projections provide numerous methods of representing a spherical surface, or any other three-dimensional body, on a plane. Each map projection distorts the surface in some way. For instance, the distortion of the Mercator projection increases away from the Equator, and is extreme in the polar regions. Thus, it is difficult to say which projection is the best. The best solution is to choose a projection that meets your specific requirements.

For more information, see Map projection.

Map Projections

The following table contains the predefined projections provided by the Map control for WinForms and their previews:

Projection Class Projection Preview
BraunStereographicProjection BraunStereographicProjection
EllipticalMercatorProjection EllipticalMercatorProjection
EqualAreaProjection EqualAreaProjection
EquidistantProjection EquidistantProjection
EquirectangularProjection EquirectangularProjection
KavrayskiyProjection KavraiskyProjection
LambertConformalConicCartesianToGeoConverter LambertCylindricalEqualAreaProjection
MillerProjection MillerProjection
SinusoidalProjection SinusoidalProjection
SphericalMercatorProjection SphericalMercatorProjection

Also, It's possible to implement custom projections. The following example shows how to get a Hammer-Aitoff projection as a special case of the map custom projection.

How to: Implement a Custom Map Projection

Customization

There are two ways to customize a map projection used in an application: create a custom ProjectionBase class descendant that specifies a custom map projection, or configure the width/height ratio for the one of the predefined map projections.

Example

The following examples demonstrate how to use predefined projections, create custom map projections and customize width/height ratio of projections.

See Also