MercatorProjection Class
Represents the Mercator map projection, used for nautical charts and world maps.
NuGet/Assembly: Carmenta.Engine.5.16.2.nupkg (in the CECore assembly)
Syntax
public class MercatorProjection : ProjectionRemarks
The well-known Mercator projection is named after Gerardus Mercator, who published a world map in 1569. This was a remarkable achievement, since the logarithm function, used to compute Mercator coordinates, was not invented until 1614.
The Mercator projection is conformal, and north is always up. Its scale is minimal on the equator and increases towards the poles. A straight line on a Mercator map is a called a rhumb line. The projection, originally designed for navigation, is used for nautical charts, and sometimes for countries near the equator. For a small-scale world map, Mercator will be very distorted near the poles, and you should consider the MillerCylindricalProjection instead. However, Mercator is the projection of choice for a multi-scale set of raster maps, when it is convenient to have the same map projection at all scales. The large-scale (detailed) maps will then preserve shapes (due to conformality), and have north up.
You can choose the Earth shape you want (sphere or ellipsoid) via the Shape argument.
The interrupted meridian
For data storage, the projected x coordinates (the eastings) have their minimum at 180° west of the CentralLongitude, and their maximum at 180° east of it. In other words: when used for data storage, a Mercator projection is interrupted along the meridian which is antipodal to the central one. However, a View behaves well when showing the interrupted meridian, by allowing eastings outside this range. If you implement your own tools, you may sometimes need to normalize the easting values.
Inheritance Hierarchy
System.Object (not available in C#)
EngineObject
ResourceObject
Projection
MercatorProjection
Platforms
Windows, Linux, Android
MercatorProjection Members
The MercatorProjection type has the following members.
Constructors
| Name | Description |
|---|---|
| MercatorProjection | Initializes a new instance of the MercatorProjection class. |
Properties
| Name | Description |
|---|---|
| Authority | Gets the name of an authority, which is often "epsg". Inherited from Projection |
| AuthorityCode | Gets the unique code for the projection instance, according to the Authority, for example "19883". Inherited from Projection |
| CentralLongitude | Gets the central longitude, also known as central meridian or longitude of origin. |
| FalseEasting | Gets the offset added to the projected x coordinates (the eastings). |
| FalseNorthing | Gets the offset added to the projected y coordinates (the northings). |
| IsDisposed | Gets a value that tells whether the current MercatorProjection has been disposed. Inherited from EngineObject |
| LengthUnit | Gets the length unit of the projected coordinates. |
 LongLat | Gets a pre-defined LongLatProjection instance. Inherited from Projection |
| Name | Gets or sets the name of the MercatorProjection. Inherited from ResourceObject |
| NativeHandle | Gets the native Carmenta Engine kernel object the current MercatorProjection represents. Inherited from EngineObject |
| ScaleFactor | A scale factor, by which all projected coordinates will be multiplied. |
| Shape | Gets a value that tells whether the Earth is represented as a sphere or as an ellipsoid. |
| SphereRadius | Gets an explicitly specified sphere radius. |
| SphereRadiusSource | Gets a value that tells how the sphere radius is determined. |
| StandardParallel | Gets the latitude of the standard parallel, on which the scale is true. |
| IUserProperties.UserProperties | Gets the AttributeSet that contains the user properties. Inherited from IUserProperties |
Methods
| Name | Description |
|---|---|
| Clone | Creates a copy of an object. Inherited from EngineObject |
| Dispose | Releases the reference to the native Carmenta Engine kernel instance the EngineObject represents. Inherited from EngineObject |
| Equals | Determines whether this instance is equal to another. Inherited from EngineObject |
| Utm | Returns one of the 120 predefined instances of Universal Transverse Mercator. Inherited from Projection |