Sistemi di riferimento spaziali

Creazione di sistemi di riferimento spaziali

Crea un sistema di riferimento spaziale tramite un identificatore EPSG (SRID)

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var srs = SpatialReferenceSystem.CreateFromEpsg(26918);

Console.WriteLine("SRS Name: {0}", srs.Name); // NAD83 / UTM zone 18N
Console.WriteLine("SRS EPSG code: {0}", srs.EpsgCode); // 26918
Console.WriteLine("Datum name: {0}", srs.GeographicDatum.Name); // North_American_Datum_1983
Console.WriteLine("Datum EPSG code: {0}", srs.GeographicDatum.EpsgCode); // 6269
Console.WriteLine("Ellipsoid name: {0}", srs.GeographicDatum.Ellipsoid.Name); // GRS 1980
Console.WriteLine("Ellipsoid EPSG code: {0}", srs.GeographicDatum.EpsgCode); // 6269

Console.WriteLine("Type: {0}", srs.Type); // Projected
Console.WriteLine("Dimensions count: {0}", srs.DimensionsCount); // 2

Console.WriteLine("First dimension name: {0}", srs.GetAxis(0).Name); // X
Console.WriteLine("First dimension direction: {0}", srs.GetAxis(0).Direction); // East

Console.WriteLine("Second dimension name: {0}", srs.GetAxis(1).Name); // Y
Console.WriteLine("Second dimension direction: {0}", srs.GetAxis(1).Direction); // North

Console.WriteLine("First dimension unit: {0}, {1}", srs.GetUnit(0).Name, srs.GetUnit(0).Factor); // metre, 1
Console.WriteLine("Second dimension unit: {0}, {1}", srs.GetUnit(1).Name, srs.GetUnit(1).Factor); // metre, 1

Crea un sistema di riferimento spaziale da WKT (Well-Known text)

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
string wkt = @"
GEOGCS[""WGS 84"",
DATUM[""WGS_1984"",
SPHEROID[""WGS 84"",6378137,298.257223563,
AUTHORITY[""EPSG"",""7030""]],
AUTHORITY[""EPSG"",""6326""]],
PRIMEM[""Greenwich"",0,
AUTHORITY[""EPSG"",""8901""]],
UNIT[""degree"",0.01745329251994328,
AUTHORITY[""EPSG"",""9122""]],
AUTHORITY[""EPSG"",""4326""]]
";
var srs = SpatialReferenceSystem.CreateFromWkt(wkt);
Console.WriteLine("SRS Name: {0}", srs.Name); // WGS 84
Console.WriteLine("SRS EPSG code: {0}", srs.EpsgCode); // 4326
Console.WriteLine("Datum name: {0}", srs.GeographicDatum.Name); // WGS_1984
Console.WriteLine("Datum EPSG code: {0}", srs.GeographicDatum.EpsgCode); // 6326
Console.WriteLine("Ellipsoid name: {0}", srs.GeographicDatum.Ellipsoid.Name); // WGS 84
Console.WriteLine("Ellipsoid EPSG code: {0}", srs.GeographicDatum.EpsgCode); // 7030

Console.WriteLine("Type: {0}", srs.Type); // Geographic
Console.WriteLine("Dimensions count: {0}", srs.DimensionsCount); // 2

Console.WriteLine("First dimension name: {0}", srs.GetAxis(0).Name); // Longitude
Console.WriteLine("First dimension direction: {0}", srs.GetAxis(0).Direction); // EAST

Console.WriteLine("Second dimension name: {0}", srs.GetAxis(1).Name); // Latitude
Console.WriteLine("Second dimension direction: {0}", srs.GetAxis(1).Direction); // NORTH

Console.WriteLine("First dimension unit: {0}, {1}", srs.GetUnit(0).Name, srs.GetUnit(0).Factor); // degree, 0.01745...
Console.WriteLine("Second dimension unit: {0}, {1}", srs.GetUnit(1).Name, srs.GetUnit(1).Factor); // degree, 0.01745...

var geogSrs = srs.AsGeographic;
Console.WriteLine("Angular unit: {0}, {1}", geogSrs.AngularUnit.Name, geogSrs.AngularUnit.Factor); // degree, 0.01745...
Console.WriteLine("Prime meridian: {0}, {1}", geogSrs.PrimeMeridian.Name, geogSrs.PrimeMeridian.Longitude); // Greenwich, 0

Crea un sistema di riferimento spaziale con parametri personalizzati

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var parameters = new ProjectedSpatialReferenceSystemParameters
{
    Name = "WGS 84 / World Mercator",
    Base = SpatialReferenceSystem.Wgs84,
    ProjectionMethodName = "Mercator_1SP",
    LinearUnit = Unit.Meter,
    XAxis = new Axis("Easting", AxisDirection.East),
    YAxis = new Axis("Northing", AxisDirection.North),
    AxisesOrder = ProjectedAxisesOrder.XY,
};
parameters.AddProjectionParameter("central_meridian", 0);
parameters.AddProjectionParameter("scale_factor", 1);
parameters.AddProjectionParameter("false_easting", 100);
parameters.AddProjectionParameter("false_northing", 100);

var projectedSrs = SpatialReferenceSystem.CreateProjected(parameters, Identifier.Epsg(3395));

Lavorare con sistemi di riferimento spaziali

Verifica il supporto del driver per un sistema di riferimento spaziale

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
Drivers.Shapefile.SupportsSpatialReferenceSystem(SpatialReferenceSystem.Wgs72); // true
Drivers.GeoJson.SupportsSpatialReferenceSystem(SpatialReferenceSystem.Wgs84); // true
Drivers.GeoJson.SupportsSpatialReferenceSystem(SpatialReferenceSystem.Wgs72); // false

Esporta il sistema di riferimento spaziale in WKT

Il testo ben noto (WKT) è un linguaggio di markup testuale per rappresentare oggetti geometrici vettoriali su una mappa, sistemi di riferimento spaziali di oggetti spaziali e trasformazioni tra sistemi di riferimento spaziali. L’API Aspose.GIS consente di creare un sistema di riferimento spaziale da WKT come mostrato nel seguente esempio di codice.

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var parameters = new ProjectedSpatialReferenceSystemParameters
{
    Name = "WGS 84 / World Mercator",
    Base = SpatialReferenceSystem.Wgs84,
    ProjectionMethodName = "Mercator_1SP",
    LinearUnit = Unit.Meter,
    XAxis = new Axis("Easting", AxisDirection.East),
    YAxis = new Axis("Northing", AxisDirection.North),
    AxisesOrder = ProjectedAxisesOrder.XY,
};
parameters.AddProjectionParameter("central_meridian", 0);
parameters.AddProjectionParameter("scale_factor", 1);
parameters.AddProjectionParameter("false_easting", 0);
parameters.AddProjectionParameter("false_northing", 0);

var projectedSrs = SpatialReferenceSystem.CreateProjected(parameters, Identifier.Epsg(3395));

string wkt = projectedSrs.ExportToWkt();
Console.WriteLine(wkt);

Confronta sistemi di riferimento spaziali

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
string wkt = @"
GEOGCS[""WGS 84"",
DATUM[""WGS_1984"",
SPHEROID[""WGS 84"",6378137,298.257223563,
AUTHORITY[""EPSG"",""7030""]],
AUTHORITY[""EPSG"",""6326""]],
PRIMEM[""Greenwich"",0,
AUTHORITY[""EPSG"",""8901""]],
UNIT[""degree"",0.01745329251994328,
AUTHORITY[""EPSG"",""9122""]],
AUTHORITY[""EPSG"",""4326""]]
";
var srs = SpatialReferenceSystem.CreateFromWkt(wkt);
srs.IsEquivalent(SpatialReferenceSystem.Wgs84); // true