Travailler avec le format de fichier Esri Gdb en C#

Bases de données géographiques ESRI (FileGDB)

Les bases de données géographiques ESRI (FileGDB) sont l’un des formats natifs les plus utilisés parmi les logiciels SIG. Aspose.GIS vous permet de travailler avec les formats de fichiers FileGDB et d’itérer sur ses entités.

Itérer sur les couches dans un fichier FileGDB

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
//File GDB is a multi layer format. This example shows how to open File GDB as a dataset (collection of layers) and access layers in it.
using (var dataset = Dataset.Open(dataDir + "ThreeLayers.gdb", Drivers.FileGdb))
{
    Console.WriteLine("FileGDB has {0} layers", dataset.LayersCount);
    for (int i = 0; i < dataset.LayersCount; ++i)
    {
        Console.WriteLine("Layer {0} name: {1}", i, dataset.GetLayerName(i));

        using (var layer = dataset.OpenLayerAt(i))
        {
            Console.WriteLine("Layer has {0} features", layer.Count);
            foreach (var feature in layer)
            {
                Console.WriteLine(feature.Geometry.AsText());
            }
        }
        Console.WriteLine("");
    }
}

Convertir FileGDB en GeoJSON

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
//This will convert FileGDB dataset with three layers into single layered GeoJSON.
VectorLayer.Convert(dataDir + "ThreeLayers.gdb", Drivers.FileGdb, dataDir + "ThreeLayers_out.json", Drivers.GeoJson);

Lire FileGDB en tant que couche

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
//FileGDB can still be opened as a single layer. In this case, the opened layer will merge all layers inside FileGDB.
using (var layer = VectorLayer.Open(dataDir + "ThreeLayers.gdb", Drivers.FileGdb))
{
    Console.WriteLine("All layers in FileGDB has {0} features", layer.Count);
    foreach (var feature in layer)
    {
        Console.WriteLine(feature.Geometry.AsText());
    }
}

Ouvrir un ShapeFile en tant qu’ensemble de données

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
//FileGDB can still be opened as a single layer. In this case, the opened layer will merge all layers inside FileGDB.
using (var layer = VectorLayer.Open(dataDir + "ThreeLayers.gdb", Drivers.FileGdb))
{
    Console.WriteLine("All layers in FileGDB has {0} features", layer.Count);
    foreach (var feature in layer)
    {
        Console.WriteLine(feature.Geometry.AsText());
    }
}

Ajouter une couche à l’ensemble de données FileGDB

Ouvrez un ensemble de données FileGDB existant et ajoutez de nouvelles couches à celui-ci.

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
// -- copy test dataset, to avoid modification of test data.

var path = RunExamples.GetDataDir() + "ThreeLayers.gdb";
var datasetPath = RunExamples.GetDataDir() + "AddLayerToFileGdbDataset_out.gdb";
RunExamples.CopyDirectory(path, datasetPath);

// --

using (var dataset = Dataset.Open(datasetPath, Drivers.FileGdb))
{
    Console.WriteLine(dataset.CanCreateLayers); // True

    using (var layer = dataset.CreateLayer("data", SpatialReferenceSystem.Wgs84))
    {
        layer.Attributes.Add(new FeatureAttribute("Name", AttributeDataType.String));
        var feature = layer.ConstructFeature();
        feature.SetValue("Name", "Name_1");
        feature.Geometry = new Point(12.21, 23.123, 20, -200);
        layer.Add(feature);
    }

    using (var layer = dataset.OpenLayer("data"))
    {
        Console.WriteLine(layer.Count); // 1
        Console.WriteLine(layer[0].GetValue<string>("Name")); // "Name_1"
    }
}

Supprimer une couche de l’ensemble de données FileGDB

Ouvrez un ensemble de données FileGDB existant et supprimez des couches de celui-ci.

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
// -- copy test dataset, to avoid modification of test data.

//var datasetPath = GetOutputPath(".gdb");
var path = RunExamples.GetDataDir() + "ThreeLayers.gdb";
var datasetPath = RunExamples.GetDataDir() + "RemoveLayersFromFileGdbDataset_out.gdb";
RunExamples.CopyDirectory(path, datasetPath);

// --

using (var dataset = Dataset.Open(datasetPath, Drivers.FileGdb))
{
    Console.WriteLine(dataset.CanRemoveLayers); // True

    Console.WriteLine(dataset.LayersCount); // 3

    // remove layer by index
    dataset.RemoveLayerAt(2);
    Console.WriteLine(dataset.LayersCount); // 2

    // remove layer by name
    dataset.RemoveLayer("layer1");
    Console.WriteLine(dataset.LayersCount); // 1
}

Créer un ensemble de données FileGDB

Crée un nouvel ensemble de données FileGDB et ajoute des couches à celui-ci.

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
Console.WriteLine(Drivers.FileGdb.CanCreateDatasets); // True
var path = RunExamples.GetDataDir() + "CreateFileGdbDataset_out.gdb";

using (var dataset = Dataset.Create(path, Drivers.FileGdb))
{
    Console.WriteLine(dataset.LayersCount); // 0

    using (var layer = dataset.CreateLayer("layer_1"))
    {
        layer.Attributes.Add(new FeatureAttribute("value", AttributeDataType.Integer));

        for (int i = 0; i < 10; ++i)
        {
            var feature = layer.ConstructFeature();
            feature.SetValue("value", i);
            feature.Geometry = new Point(i, i);
            layer.Add(feature);
        }
    }

    using (var layer = dataset.CreateLayer("layer_2"))
    {
        var feature = layer.ConstructFeature();
        feature.Geometry = new LineString(new[]
        {
            new Point(1, 2),
            new Point(3, 4),
        });
        layer.Add(feature);
    }

    Console.WriteLine(dataset.LayersCount); // 2
}

Créer un ensemble de données FileGDB avec une seule couche à l’aide de l’API VectorLayer

Cet exemple crée un ensemble de données FileGDB avec une seule couche à l’aide de l’API VectorLayer.

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var path = RunExamples.GetDataDir() + "CreateFileGdbDatasetWithSingleLayer_out.gdb";
var options = new FileGdbOptions();
using (var layer = VectorLayer.Create(path, Drivers.FileGdb, options, SpatialReferenceSystem.Wgs84))
// this 'using' is equivalent to
// using (var dataset = Dataset.Create(path, Drivers.FileGdb))
// using (var layer = Dataset.CreateLayer("layer"))
{
    var feature = layer.ConstructFeature();
    feature.Geometry = new LineString(new[]
    {
        new Point(1, 2),
        new Point(3, 4),
    });
    layer.Add(feature);
}

using (var dataset = Dataset.Open(path, Drivers.FileGdb))
using (var layer = dataset.OpenLayer("layer"))
{
    Console.WriteLine("Features count: {0}", layer.Count); // 1
}

Convertir une couche GeoJSON en une couche d’ensemble de données FileGDB

Créez une nouvelle couche dans FileGDB et ajoutez des données de la couche GeoJSON à celle-ci.

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var geoJsonPath = RunExamples.GetDataDir() + "ConvertGeoJsonLayerToLayerInFileGdbDataset_out.json";
using (VectorLayer layer = VectorLayer.Create(geoJsonPath, Drivers.GeoJson))
{
    layer.Attributes.Add(new FeatureAttribute("name", AttributeDataType.String));
    layer.Attributes.Add(new FeatureAttribute("age", AttributeDataType.Integer));

    Feature firstFeature = layer.ConstructFeature();
    firstFeature.Geometry = new Point(33.97, -118.25);
    firstFeature.SetValue("name", "John");
    firstFeature.SetValue("age", 23);
    layer.Add(firstFeature);

    Feature secondFeature = layer.ConstructFeature();
    secondFeature.Geometry = new Point(35.81, -96.28);
    secondFeature.SetValue("name", "Mary");
    secondFeature.SetValue("age", 54);
    layer.Add(secondFeature);
}

// --

// -- copy test dataset, to avoid modification of test data.
            
var sourceFile = RunExamples.GetDataDir() + "ThreeLayers.gdb";
var destinationFile = RunExamples.GetDataDir() + "ThreeLayersCopy_out.gdb";
RunExamples.CopyDirectory(sourceFile, destinationFile);

// --

using (var geoJsonLayer = VectorLayer.Open(geoJsonPath, Drivers.GeoJson))
{
    using (var fileGdbDataset = Dataset.Open(destinationFile, Drivers.FileGdb))
    using (var fileGdbLayer = fileGdbDataset.CreateLayer("new_layer", SpatialReferenceSystem.Wgs84))
    {
        fileGdbLayer.CopyAttributes(geoJsonLayer);
        foreach (var feature in geoJsonLayer)
        {
            fileGdbLayer.Add(feature);
        }
    }
}

Lire l’OBJECTID d’une couche d’ensemble de données FileGDB

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
using (var dataset = Dataset.Open(path, Drivers.FileGdb))
using (var layer = dataset.OpenLayer("layer"))
{
    foreach (var feature in layer)
    {
        Console.WriteLine(feature.GetValue<int>("OBJECTID"));
    }
}

Spécifier une grille de précision pour la couche FileGDB

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var path = RunExamples.GetDataDir() + "PrecisionGrid_out.gdb";
using (var dataset = Dataset.Create(path, Drivers.FileGdb))
{
    var options = new FileGdbOptions
    {
        // specify coordinate precision grid parameters (origins and scales for coordinates)
        CoordinatePrecisionGrid = new FileGdbCoordinatePrecisionGrid
        {
            // all our coordinates must be more than (-400, -400) point
            XOrigin = -400,
            YOrigin = -400,

            // the write precision is 10 digits after the decimal point
            XYScale = 1e10,

            // M values are started at 0 and precision is 4 digits after the decimal point
            MOrigin = 0,
            MScale = 1e4,
        },

        // throw whenever an attempt to write coordinate that does not fit precision grid is detected
        EnsureValidCoordinatesRange = true,
    };

    using (var layer = dataset.CreateLayer("layer_name", options, SpatialReferenceSystem.Wgs84))
    {
        var feature = layer.ConstructFeature();
        feature.Geometry = new Point(10, 20) { M = 10.1282 };
        layer.Add(feature);

        feature = layer.ConstructFeature();
        // X == -410 is less than XOrigin, so an exception is thrown
        feature.Geometry = new Point(-410, 0) { M = 20.2343 };
        try
        {
            layer.Add(feature);
        }
        catch (GisException e)
        {
            Console.WriteLine(e.Message); // X value -410 is out of valid range.
        }
    }
}

Spécifier les tolérances pour la couche FileGDB

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var path = RunExamples.GetDataDir() + "TolerancesForFileGdbLayer_out.gdb";
using (var dataset = Dataset.Create(path, Drivers.FileGdb))
{
    var options = new FileGdbOptions
    {
        XYTolerance = 0.001,
        ZTolerance = 0.1,
        MTolerance = 0.1,
    };

    using (var layer = dataset.CreateLayer("layer_name", options))
    {
        // layer is created with the provided tolerances and some ArcGIS features/tools will use it
    }
}

Spécifier les noms des champs ObjectId et Geometry

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var path = RunExamples.GetDataDir() + "NamesOfObjectIdAndGeometryFields_out.gdb";
using (var dataset = Dataset.Create(path, Drivers.FileGdb))
{
    var options = new FileGdbOptions
    {
        // name object ID field 'OID' rather than the default 'OBJECTID'.
        ObjectIdFieldName = "OID",

        // name geometry field 'POINT' rather than the default 'SHAPE'.
        GeometryFieldName = "POINT",
    };

    using (var layer = dataset.CreateLayer("layer_name", options, SpatialReferenceSystem.Wgs84))
    {
        var feature = layer.ConstructFeature();
        feature.Geometry = new Point(12.32, 34.21);
        layer.Add(feature);
    }

    using (var layer = dataset.OpenLayer("layer_name"))
    {
        var feature = layer[0];
        Console.WriteLine(feature.GetValue<int>("OID")); // 1
    }
}