Read GML Geography Markup Language files in C#

Geography Markup Language (GML)

Aspose.GIS provides the capability to read features from Geography Markup Language (GML). It lets you specify the schema option in case there is one.

Reading Features from GML File by Specifying 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"));
    }
}

Reading Features from GML File without Specifying 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"));
    }
}