PostGIS - کار با لایه‌های GIS در پایگاه‌های داده PostgreSQL با استفاده از C#

PostgreSQL (افزونه PostGIS) یکی از پرکاربردترین پایگاه‌های داده در میان نرم‌افزارهای GIS است. Aspose.GIS به شما امکان می‌دهد با پایگاه‌های داده PostgreSQL کار کنید.

تکرار بر روی لایه‌ها در پایگاه داده PostGis

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
// First, we create the connection to the PostgreSQL with Npgsql library (https://www.nuget.org/packages/Npgsql/)
// Then, we pass this connection to Dataset.Open method in order to access tables in the PostgreSQL.
using (var connection = new NpgsqlConnection(postgreSqlConnectionString))
{
    connection.Open();
    using (var ds = Dataset.Open(connection, Drivers.PostGis))
    {
        // Only spatial tables are exported as layers, so the following code will list all tables
        // that have geometry column.
        for (int i = 0; i < ds.LayersCount; ++i)
        {
            Console.WriteLine(ds.GetLayerName(i));
        }
    }
}

اضافه کردن یک لایه جدید در پایگاه داده PostGis

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
// First, we create the connection to the PostgreSQL with Npgsql library (https://www.nuget.org/packages/Npgsql/)
using (var connection = new NpgsqlConnection(postgreSqlConnectionString))
{
    connection.Open();
    // Then, we pass this connection to Dataset.Open method in order to access tables in the PostgreSQL.
    using (var ds = Dataset.Open(connection, Drivers.PostGis))
    {
        // create table with the name "features_table" and fill it with data.
        using (var layer = ds.CreateLayer("features_table"))
        {
            layer.Attributes.Add(new FeatureAttribute("name", AttributeDataType.String) { Width = 50 });

            var feature = layer.ConstructFeature();
            feature.SetValue("name", "Name1");
            feature.Geometry = Geometry.FromText("POINT (10 20 30)");
            layer.Add(feature);

            feature = layer.ConstructFeature();
            feature.SetValue("name", "Name2");
            feature.Geometry = Geometry.FromText("POINT (-10 -20 -30)");
            layer.Add(feature);
        }
    }
}

صادر کردن یک لایه از پایگاه داده PostGis به یک فرمت فایل

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
var outputPath = Path.Combine(RunExamples.GetDataDir(), "postgres_out.shp");

// First, we create the connection to the PostgreSQL with Npgsql library (https://www.nuget.org/packages/Npgsql/)
// Then, we pass this connection to Dataset.Open method in order to access tables in the PostgreSQL.
using (var connection = new NpgsqlConnection(postgreSqlConnectionString))
{
    connection.Open();
    using (var ds = Dataset.Open(connection, Drivers.PostGis))
    {
        // open table with the name "features_table" in Postgres database and save it to the shapefile.
        using (var table = ds.OpenLayer("features_table"))
        {
            table.SaveTo(outputPath, Drivers.Shapefile);
        }
    }
}