Práce a generování Shapefile pomocí knihovny C#

Vytvoření Shapefile

Aspose.GIS for .NET vám umožňuje vytvářet nové Shapefile a přidávat do něj informace. Shapefile může být naplněn informacemi o Atributech a k těmto lze přidávat Prvky (Features).

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
using (VectorLayer layer = VectorLayer.Create(dataDir + "NewShapeFile_out.shp", Drivers.Shapefile))
{
    // add attributes before adding features
    layer.Attributes.Add(new FeatureAttribute("name", AttributeDataType.String));
    layer.Attributes.Add(new FeatureAttribute("age", AttributeDataType.Integer));
    layer.Attributes.Add(new FeatureAttribute("dob", AttributeDataType.DateTime));

    // case 1: sets values
    Feature firstFeature = layer.ConstructFeature();
    firstFeature.Geometry = new Point(33.97, -118.25);
    firstFeature.SetValue("name", "John");
    firstFeature.SetValue("age", 23);
    firstFeature.SetValue("dob", new DateTime(1982, 2,5, 16, 30,0));
    layer.Add(firstFeature);
    
    Feature secondFeature = layer.ConstructFeature();
    secondFeature.Geometry = new Point(35.81, -96.28);
    secondFeature.SetValue("name", "Mary");
    secondFeature.SetValue("age", 54);
    secondFeature.SetValue("dob", new DateTime(1984, 12, 15, 15, 30, 0));
    layer.Add(secondFeature);

    // case 2: sets new values for all of the attributes.
    Feature thirdFeature = layer.ConstructFeature();
    secondFeature.Geometry = new Point(34.81, -92.28);
    object[] data = new object[3] {"Alex", 25, new DateTime(1989, 4, 15, 15, 30, 0)};
    secondFeature.SetValues(data);
    layer.Add(thirdFeature);
}

Vytvoření vektorové vrstvy se systémem prostorových referencí

// 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));

using (var layer = Drivers.Shapefile.CreateLayer(dataDir + "filepath_out.shp", new ShapefileOptions(), projectedSrs))
{
    var feature = layer.ConstructFeature();
    feature.Geometry = new Point(1, 2);
    layer.Add(feature);

    feature = layer.ConstructFeature();
    feature.Geometry = new Point(1, 2) { SpatialReferenceSystem = SpatialReferenceSystem.Nad83 };
    try
    {
        layer.Add(feature); // geometry of feature has different SRS - exception is thrown
    }
    catch (GisException e)
    {
        Console.WriteLine(e.Message);
    }
}

using (var layer = Drivers.Shapefile.OpenLayer(dataDir + "filepath_out.shp"))
{
    var srsName = layer.SpatialReferenceSystem.Name; // "WGS 84 / World Mercator"
    layer.SpatialReferenceSystem.IsEquivalent(projectedSrs); // true
}

Přidání nových prvků do Shapefile

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
string path = Path.Combine(dataDir, "point_xyz_out", "point_xyz.shp");

using (var layer = Drivers.Shapefile.EditLayer(path))
{
    var feature = layer.ConstructFeature();
    feature.SetValue<int>("ID", 5);
    feature.Geometry = new Point(-5, 5) {Z = 2};
    layer.Add(feature);
}

Převod Polygon Shape File na Line String Shape File

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
using (VectorLayer source = VectorLayer.Open(dataDir + "PolygonShapeFile.shp", Drivers.Shapefile))
{
    using (VectorLayer destination = VectorLayer.Create(dataDir + "PolygonShapeFileToLineShapeFile_out.shp", Drivers.Shapefile))
    {
        foreach (Feature sourceFeature in source)
        {
            Polygon polygon = (Polygon)sourceFeature.Geometry;
            LineString line = new LineString(polygon.ExteriorRing);
            Feature destinationFeature = destination.ConstructFeature();
            destinationFeature.Geometry = line;
            destination.Add(destinationFeature);
        }
    }
}