Leggi i file Geography Markup Language GML in C#

Geography Markup Language (GML)

Aspose.GIS fornisce la capacità di leggere le feature da Geography Markup Language (GML). Consente di specificare l’opzione dello schema nel caso in cui esista.

Lettura delle Feature da un File GML Specificando lo Schema

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
GmlOptions options = new GmlOptions
{
    // In this example we specify custom schemaLocation, since there is no 'schemaLocation' in GML file.
    SchemaLocation = "http://www.aspose.com  schema.xsd",
    LoadSchemasFromInternet = false,
};

Console.WriteLine("");
Console.WriteLine("custom schema location...");
using (VectorLayer layer = VectorLayer.Open(dataDir + "file_without_schema_location.gml", Drivers.Gml, options))
{
    foreach (Feature feature in layer)
    {
        Console.WriteLine(feature.GetValue<string>("attribute"));
    }
}

Lettura delle Feature da un File GML senza Specificare lo Schema

// For complete examples and data files, please go to https://github.com/aspose-gis/Aspose.GIS-for-.NET
// Case 1: we try to load schema from Internet.
// first, we create an instance of GmlOptions class.
GmlOptions options = new GmlOptions
{
    // In order to read GML layers features description, Aspose.GIS reads XML schema attached to it.
    // Usually, it is specified in GML files root tag as 'schemaLocation' attribute. If it is not, you need to specify GML schema location
    // youself. In this examples we don't specify it (keep it null), so Aspose.GIS will try to read schema location from XML file.
    SchemaLocation = null,
    // 'schemaLocation' may contain references to schemas located on the Internet. In this case, you need to set this property to 'true' in
    // order to allow Aspose.GIS to load schemas from internet.
    // Basically, if you don't mind Aspose.GIS using internet, you can always keep this true.
    LoadSchemasFromInternet = true,
};

// then, we pass it to 'VectorLayer.Open'
Console.WriteLine("from internet loading...");
using (VectorLayer layer = VectorLayer.Open(dataDir + "file.gml", Drivers.Gml, options))
{
    foreach (Feature feature in layer)
    {
        Console.WriteLine(feature.GetValue<string>("attribute"));
    }
}

// Case 2: we try to restore the attributes schema by data in file.
Console.WriteLine("");
Console.WriteLine("restoration by file data...");
using (VectorLayer layer = VectorLayer.Open(dataDir + "file.gml", Drivers.Gml, new GmlOptions(){RestoreSchema = true}))
{
    foreach (Feature feature in layer)
    {
        Console.WriteLine(feature.GetValue<string>("attribute"));
    }
}