GeographicLib is a small set of C++ classes for performing conversions between geographic, UTM, UPS, MGRS, geocentric, and local cartesian coordinates,for gravity (e.g., EGM2008), geoid height and geomagnetic field (e.g., WMM2020) calculations, and for solving geodesic problems.
GeographicLib.NET is a native .NET implementation of GeographicLib written in pure C#.
GeographicLib is a small set of C++ classes for performing conversions between geographic,
UTM, UPS, MGRS, geocentric, and local cartesian coordinates,for gravity (e.g., EGM2008), geoid height and geomagnetic field (e.g., WMM2020) calculations,
and for solving geodesic problems.
GeographicLib.NET is a native .NET implementation of GeographicLib written in pure C#.
What's different from NETGeographicLib
Unlike NETGeographicLib, GeographicLib.NET is implemented in pure C# without binding the C++ GeograpbicLib library by using C++/CLI or P/Invoke, thus achieves higher level of portability.
You should be able to use GeographicLib.NET with any target framework and platform that supports .NET Standard 2.0 or above.
Features
Bellow is a list of implemented features.
Projections (AlbersEqualArea, AzimuthalEquidistant, CassiniSoldner, Gnomonic, LambertConformalConic, PolarStereographic and TransverseMercator)
Geocodes (, , , and )
GARS
Geohash
Georef
MGRS
OSGB
Coordinate conversions (UTMUPS, Geocentric and LocalCartesian)
Coordinate parsing/formatting (DMS and GeoCoords)
Geodesic (Geodesic, GeodesicLine, GeodesicExact and GeodesicLineExact)
Geodesic intersections (Intersect)
Rhumb (Rhumb and RhumbLine)
PolygonArea (PolygonArea<T>, PolygonArea, PolygonAreaExact and PolygonAreaRhumb)
Geoid (Geoid)
GravityModel (GravityCircle, NormalGravity and GravityModel)
MagneticModel (MagneticModel, MagneticCircle)
Auxiliary classes (MathEx, Ellipoid, EllipticFunction, SphericalHarmonic, AuxAngle, AuxLatitude and DAuxLatitude)
Geodesic geod = Geodesic.WGS84;
Intersect inter = new Intersect(geod);
IGeodesicLine
lineX = geod.Line(0, 0, 45),
lineY = geod.Line(45, 10, 135);
// Find displacement to closest intersection.
// Where point.X is the displacement from the starting point of lineX,
// and point.Y is the displacement from the starting point of lineY.
Point point = inter.Closest(lineX, lineY);
// Get the position of the intersection point by using the displacement on lineX.
lineX.Position(point.X, out double latx, out double lonx);
// Get the position of the intersection point by using the displacement on lineY.
lineY.Position(point.Y, out double laty, out double lony);
// (latx, lonx) and (laty, lony) should be pointing to the same location.
Assert.AreEqual(latx, laty, 1e-12);
Assert.AreEqual(lonx, lony, 1e-12);
Mathematical Functions
GeographicLib uses several C mathematical functions that are not available in all versions of .NET. These functions are:
remquo
frexp
sincos (available since .NET 7.0, but not used due to this issue)
hypot (available since .NET 7.0, but not used due to this issue)
log1p (a naive implementation is available since .NET 7.0, not used by GeographicLib.NET)
expm1 (a naive implementation is available since .NET 7.0, not used by GeographicLib.NET)
exp2 (a naive implementation is available since .NET 7.0, not used by GeographicLib.NET)
log2 (available since .NET 5.0)
fma (available since .NET 5.0)
scalbn (available since .NET 5.0)
copysign (available since .NET 5.0)
atanh (available since .NET Standard 2.1)
asinh (available since .NET Standard 2.1)
cbrt (available since .NET Standard 2.1)
GeographicLib.NET provides managed implementations (ported from musl libc) and platform dependent native C wrappers for these functions.
By default, the library will use the managed implementation when the corresponding math function is not provided by .NET runtime.
You can also force the library to use platform dependent native C wrappers, by setting GeographicLib.MathEx.UseManagedCMath property to false.
GeographicLib.NET adopts changes made in GeographicLib and aligns its version number with GeographicLib releases.
Bellow is a list of stable releases of GeographicLib.NET and changes made in .NET side in each release.
For changes adopted from GeographicLib, please refer the its change log here.
Version 2.3.1 (released 2024/03/20)
NEW
Improve performance of Geodesic.Direct, Rhumb.Direct, GeodesicExact.Direct, GeodesicExact.Inverse and their overloads/variants. These are now heap allocation free.
Allow constructing MagneticModel and GravityModel from Stream and byte array. (#30)
AuxLatitude now implements IEllipsoid interface.
Parameter p0 of Intersect.Closest() now defaults to Point.Zero.
FIX
Fixed wrong GravityFlags handling in GravityCircle class.
Version 2.3.0 (released 2024/02/23)
NEW
Target .NET 7.0 and .NET 8.0.
Add managed implementation and libc wrapper for exp2.
Managed implementations and libc wrappers for log1p, expm1 and exp2 are now used for all versions of .NET, because the implementations provided by .NET runtime are just wrappers over Math.Log and Math.Pow.
Fixed an issue where number and date time parsing may fail or produce unexpected result when working with
number and date time formats provided by CultureInfo.CurrentCulture. This fixes issue #27.
Version 2.0.0 (released 2022/08/24)
NEW
Add IPolygonArea interface to provide better support for unit testing and dependency injection.
Add Count and IsPolyline properties (corresponding to NumPoints and Polyline methods in GeographicLib) to PolygonArea.
Add a new method Utility.FractionalYear which can parse floating point number and date time string as fractional year.
Modify overloads of Forward and Reverse in AlbersEqualArea, AzimuthalEquidistant, CassiniSoldner and LambertConformalConic to return coordinates as tuples.
Modify methods using out parameters defined in NormalGravity, GravityModel, GravityCircle, MagneticModel and MagnegticCircle to return results as tuples.
NEW
Add constructor overloads that accept IEllipsoid as parameter for AlbersEqualArea and LambertConformalConic.
Add managed implementation of log2.
Add overloads of Direct and Inverse in Geodesic/GeodesicLine, GeodesicExact/GeodesicLineExact and Rhumb/RhumbLineExact,
that return the computation results as a single object.
Add definitions of popular reference ellipsoids in Ellipsoid class.
FIX
Fix stack overflow bug for Forward(double lon0, double lat, double lon) and Reverse(double lon0, double x, double y) in TransverseMercatorExact.
