Implements the Mercator projection.

This map projection introduced in 1569 by Gerardus Mercator. It is often described as a cylindrical projection, but it must be derived mathematically. The meridians are equally spaced, parallel vertical lines, and the parallels of latitude are parallel, horizontal straight lines, spaced farther and farther apart as their distance from the Equator increases. This projection is widely used for navigation charts, because any straight line on a Mercator-projection map is a line of constant true bearing that enables a navigator to plot a straight-line course. It is less practical for world maps because the scale is distorted; areas farther away from the equator appear disproportionately large. On a Mercator projection, for example, the landmass of Greenland appears to be greater than that of the continent of South America; in actual area, Greenland is smaller than the Arabian Peninsula.

Inheritance: MapProjection
Mercator Class Documentation
Example #1
0
 /// <summary>
 /// Returns the inverse of this projection.
 /// </summary>
 /// <returns>IMathTransform that is the reverse of the current projection.</returns>
 public override IMathTransform Inverse()
 {
     if (_inverse==null)
     {
         _inverse = new Mercator(this._Parameters, ! _isInverse);
     }
     return _inverse;
 }
Example #2
0
        private static IMathTransform CreateCoordinateOperation(IProjection projection, IEllipsoid ellipsoid)
        {
            List<ProjectionParameter> parameterList = new List<ProjectionParameter>(projection.NumParameters);
            for (int i = 0; i < projection.NumParameters; i++)
                parameterList.Add(projection.GetParameter(i));

            parameterList.Add(new ProjectionParameter("semi_major", ellipsoid.SemiMajorAxis));
            parameterList.Add(new ProjectionParameter("semi_minor", ellipsoid.SemiMinorAxis));

            IMathTransform transform = null;
            switch (projection.ClassName.ToLower())
            {
                case "mercator_1sp":
                case "mercator_2sp":
                    //1SP
                    transform = new Mercator(parameterList);
                    break;
                case "transverse_mercator":
                    transform = new TransverseMercator(parameterList);
                    break;
                case "albers":
                    transform = new AlbersProjection(parameterList);
                    break;
                case "lambert_conformal_conic":
                case "lambert_conformal_conic_2sp":
                    transform = new LambertConformalConic2SP(parameterList);
                    break;
                default:
                    throw new NotSupportedException(String.Format("Projection {0} is not supported.", projection.ClassName));
            }
            return transform;
        }
Example #3
0
		private static IMathTransform CreateCoordinateOperation(IProjection projection, IEllipsoid ellipsoid, ILinearUnit unit)
		{
			List<ProjectionParameter> parameterList = new List<ProjectionParameter>(projection.NumParameters);
			for (int i = 0; i < projection.NumParameters; i++)
				parameterList.Add(projection.GetParameter(i));

			parameterList.Add(new ProjectionParameter("semi_major", ellipsoid.SemiMajorAxis));
			parameterList.Add(new ProjectionParameter("semi_minor", ellipsoid.SemiMinorAxis));
			parameterList.Add(new ProjectionParameter("unit", unit.MetersPerUnit));
			IMathTransform transform = null;
			switch (projection.ClassName.ToLower(System.Globalization.CultureInfo.InvariantCulture).Replace(' ', '_'))
			{
				case "mercator":
				case "mercator_1sp":
				case "mercator_2sp":
					//1SP
					transform = new Mercator(parameterList);
					break;
				case "transverse_mercator":
					transform = new TransverseMercator(parameterList);
					break;
				case "albers":
				case "albers_conic_equal_area":
					transform = new AlbersProjection(parameterList);
					break;
				case "lambert_conformal_conic":
				case "lambert_conformal_conic_2sp":
				case "lambert_conic_conformal_(2sp)":
					transform = new LambertConformalConic2SP(parameterList);
					break;
				default:
					throw new NotSupportedException(String.Format("Projection {0} is not supported.", projection.ClassName));
			}
			return transform;
		}