LuciadCPillar encoding support for GeoPackage

LuciadCPillar offers support for the creation of GeoPackage data sets and files. It can either create a GeoPackage data set and feature model from scratch for a given data type, or export an existing feature model. The encoding process supports both the creation of new files and the addition of GeoPackage data sets to existing files.

Creating an empty GeoPackage data set in a file

You can create an empty GeoPackage data set to fill up with feature data later. You can create such an empty data set in an existing GeoPackage file or in a new file.

To create a new data set, you need a file path, a data typedata typedata type and a coordinate referencecoordinate referencecoordinate reference. The file path either points to a new file or to an existing GeoPackage file. You must pass the data type and the reference to the GeoPackageFeatureModelCreateOptionsGeoPackageFeatureModelCreateOptionsGeoPackageFeatureModelCreateOptions. Then you call the createEmptyGeoPackageDataSetcreateEmptyGeoPackageDataSetcreateEmptyGeoPackageDataSet function, as shown in the code sample.

The function creates the data set and also decodes an editable IFeatureModelIFeatureModelIFeatureModel from the new data set and returns it to you, ready for use.

See the API documentationAPI documentationAPI documentation for more information.

Program: Create an empty GeoPackage data set
std::string path = "test/resources/Data/GeoPackage/newGeoPackage.gpkg";
DataType dataType = createDataType();
auto reference = *CoordinateReferenceProvider::create("EPSG:4326");
auto options = GeoPackageFeatureModelCreateOptions::newBuilder().dataType(dataType).coordinateReference(reference).build();
auto expectedFeatureModel = GeoPackageModelEncoder::createEmptyGeoPackageDataSet(path, options);
if (!expectedFeatureModel) {
  std::cout << "Failed to create feature model: " + expectedFeatureModel.error().getMessage();
}
std::shared_ptr<IFeatureModel> featureModel = *expectedFeatureModel;
DataType dataType = CreateDataType();
var path = "test/resources/Data/GeoPackage/newGeoPackage.gpkg";
var reference = CoordinateReferenceProvider.Create("epsg:4326");
var options = GeoPackageFeatureModelCreateOptions.NewBuilder()
    .CoordinateReference(reference)
    .DataType(dataType)
    .Build();
try
{
    IFeatureModel featureModel = GeoPackageModelEncoder.CreateEmptyGeoPackageDataSet(path, options);
}
catch (IOException e)
{
    Console.WriteLine("Failed to create feature model: " + e.Message);
}
DataType dataType = createDataType();
String path = "resources/Data/GeoPackage/newGeoPackage.gpkg";
CoordinateReference reference = CoordinateReferenceProvider.create("epsg:4326");
GeoPackageFeatureModelCreateOptions options = GeoPackageFeatureModelCreateOptions.newBuilder().dataType(dataType).coordinateReference(reference).build();
try {
    GeoPackageModelEncoder.createEmptyGeoPackageDataSet(path, options);
} catch (IOException e) {
    Log.w("gpkg", "Failed to export feature model: " + e.getMessage());
}

Exporting an existing feature model

When you’re exportingexportingexporting an existing feature model, you need to specify the file path only, pointing either to a new file or an existing file. Setting the optionsoptionsoptions is optional. See the API documentationAPI documentationAPI documentation for more information.

Program: Exporting a feature model to a GeoPackage file
std::shared_ptr<IFeatureModel> featureModel = getFeatureModel();
std::string path = "test/resources/Data/GeoPackage/newGeoPackage.gpkg";
auto result = GeoPackageModelEncoder::exportFeatureModel(path, featureModel);
if (!result) {
  std::cout << "Failed to export feature model: " + result.error().getMessage();
}
var path = "test/resources/Data/GeoPackage/newGeoPackage.gpkg";
IFeatureModel featureModel = GetFeatureModel();
try
{
    GeoPackageModelEncoder.ExportFeatureModel(path, featureModel);
}
catch (IOException e)
{
    Console.WriteLine("Failed to export feature model: " + e.Message);
}
IFeatureModel featureModel = getFeatureModel();
String path = "resources/Data/GeoPackage/newGeoPackage.gpkg";
try {
    GeoPackageModelEncoder.exportFeatureModel(path, featureModel);
} catch (IOException e) {
    Log.w("gpkg", "Failed to create feature model: " + e.getMessage());
}

Exporting or persisting a model

When you already have an editable GeoPackage IFeatureModelIFeatureModelIFeatureModel and you want to persist the changes you’ve made to it, you don’t have to export it. Instead, use the FeatureModelPersistenceManagerFeatureModelPersistenceManagerFeatureModelPersistenceManager as explained in the GeoPackage editing article.