עבודה עם פורמט קובץ Esri Gdb בשפה C#

מסדי נתונים גיאוגרפיים של ESRI (FileGDB)

מסדי נתונים גיאוגרפיים של ESRI (FileGDB) הם אחד מהפורמטים המקוריים הנפוצים ביותר בקרב תוכנות GIS. Aspose.GIS מאפשר לך לעבוד עם פורמטי קבצי FileGDB ולעבור על התכונות שלו.

מעבר על שכבות בקובץ 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("");
    }
}

המרת FileGDB ל- 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);

קריאת FileGDB כשכבה

// 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());
    }
}

פתיחת ShapeFile כ dataset

// 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());
    }
}

הוספת שכבה ל dataset של FileGDB

פתיחת dataset קיים של FileGDB והוספת שכבות חדשות אליו

// 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"
    }
}

הסרת שכבה מ dataset של FileGDB

פתיחת dataset קיים של FileGDB והסרת שכבות ממנו.

// 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
}

יצירת dataset של FileGDB

יוצר dataset חדש של FileGDB ומוסיף אליו שכבות.

// 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
}

יצירת dataset של FileGDB עם שכבה אחת באמצעות API של VectorLayer

דוגמה זו יוצרת dataset של FileGDB עם שכבה אחת באמצעות API של 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
}

המרת שכבת GeoJSON ל layer ב dataset של FileGDB

יצירת Layer חדש ב FileGDB והוספת נתונים משכבת GeoJSON אליו.

// 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);
        }
    }
}

קריאת OBJECTID משכבת dataset של 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"));
    }
}

ציון רשת דיוק עבור שכבת 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.
        }
    }
}

ציון סבילות עבור שכבת 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
    }
}

ציון שמות של שדות ObjectId ו 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
    }
}