Adding layer to GeoPackage using PyQGIS

Question

How to add layers (vector or raster to an existing GeoPackage)?

While loading an existing layer of a GeoPackage is quite trivial:

from qgis.utils import iface
path = '/home/matteo/geopackage.gpkg|layername={}'.format('admin')
iface.addVectorLayer(path, 'admin', 'ogr')

I couldn't find information about adding them via PyQGIS.

Answer 1

You need to use QgsVectorFileWriter.writeAsVectorFormat. If you store one layer per GPKG file you just need:

QGIS 3:

# imports
from qgis.utils import iface
from qgis.core import QgsProject, QgsVectorFileWriter
get layer list by one of:
lyrs = iface.layerTreeView().selectedLayers()
lyrs = QgsProject.instance().layerTreeRoot().children()
select layer
lyr = lyrs[0]
_writer = QgsVectorFileWriter.writeAsVectorFormat(lyr, r"C:\gisData\layer.gpkg")

QGIS 2:

# imports
from qgis.utils import iface
from qgis.core import QgsMapLayerRegistry, QgsVectorFileWriter
get layer list by one of:
lyrs = iface.mapCanvas().layers() # OR
lyrs = QgsMapLayerRegistry.instance().mapLayers()
select layer
lyr = lyrs[0]
_writer = QgsVectorFileWriter.writeAsVectorFormat(lyr, r"C:\gisData\layer.gpkg")

If you want save more than one layer in GeoPackage file you should set additional options.

from qgis.core import QgsMapLayer, QgsVectorFileWriter
for lyr in filter(lambda l: l.type() == QgsMapLayer.VectorLayer, lyrs):
    options = QgsVectorFileWriter.SaveVectorOptions()
    options.actionOnExistingFile = QgsVectorFileWriter.CreateOrOverwriteLayer 
    options.layerName = "_".join(lyr.name().split(' '))
    _writer = QgsVectorFileWriter.writeAsVectorFormat(lyr, gpkgPath, options)
    if _writer:
        print(lyr.name(), _writer)

PyQGIS should have similar interface for raster layers. In my opinion easiest way to find out is to install IPyConsole plugin and use PyQGIS API.

Answer 2

Write a layer to a GeoPackage

The easiest way to save a vector layer to GeoPackage is to use the "Save vector features to file" algorithm, available from QGIS 3.16 on.

import processing
params = {'INPUT': existing_layer,
          'OUTPUT': '/tmp/new_gpkg.gpkg',
          'LAYER_NAME': 'new_layer_name'}
processing.run("native:savefeatures", params)

Note that you can pass additional GDAL/OGR options by passing DATASOURCE_OPTIONS and LAYER_OPTIONS parameters.

Warning: If you pass a path to an existing GeoPackage as OUTPUT parameter, this algorithm will replace your GeoPackage by a new one!!!

Adding an additional layer to an existing GeoPackage

Option 1

If you want to add a layer to an existing GeoPackage (and still preserve other existing layers!), you can use the GDAL's "Convert format" algorithm in this way:

import processing
params = {'INPUT': existing_layer,
          'OPTIONS':'-update -nln my_new_layer_name',
          'OUTPUT':'/tmp/existing_db.gpkg'}
processing.run("gdal:convertformat", params)

Where -update indicates the existing GeoPackage shouldn't be overwritten but updated, and -nln (optional) indicates the layer name you want your existing_layer to have when created into the existing GeoPackage.

Option 2

You could also use the "Package layers" algorithm, which allows you to add several layers at once, in this way:

import processing
params = {'LAYERS': [layer1, layer2],
          'OUTPUT': '/tmp/existing_db.gpkg',
          'OVERWRITE': False,  # Important!
          'SAVE_STYLES': False,
          'SAVE_METADATA': False,
          'SELECTED_FEATURES_ONLY': False}
processing.run("native:package", params)

Note: Set the rest of parameters as you like, but the OVERWRITE one should be set to False if you want to update the existing GeoPackage.

Answer 3

I have investigated this code an create a script like it works very well for exporting raster layer to GeoPackage:

from osgeo import ogr
from qgis.core import QgsRasterLayer, QgsRasterFileWriter, QgsRasterPipe, QgsRasterProjector
ds = ogr.Open(self.projectGpkg, True)
source = QgsRasterLayer(layerSource, 'rasterLayer', 'gdal')
if source.isValid():
    provider = source.dataProvider()
    fw = QgsRasterFileWriter(self.projectGpkg)
    fw.setOutputFormat('gpkg')
    fw.setCreateOptions(["RASTER_TABLE=" + str(tableName), 'APPEND_SUBDATASET=YES'])
pipe = QgsRasterPipe()
if pipe.set(provider.clone()) is True:
    projector = QgsRasterProjector()
    projector.setCrs(provider.crs(), provider.crs())
    if pipe.insert(2, projector) is True:
        if fw.writeRaster(pipe, provider.xSize(), provider.ySize(), provider.extent(), provider.crs()) == 0:
            print("ok")
        else:
            print("error")

ds = None

For reading raster layer in GeoPackage:

from qgis.core import QgsRasterLayer
rlayer = QgsRasterLayer('GPKG:' + str(self.projectGpkg) + ':tableName', "layerName")

Answer 4

For raster layers, use the GDAL's "Translate (convert format)" algorithm:

import processing
params = { 
    'COPY_SUBDATASETS' : False, 
    'DATA_TYPE' : 0, 
    'EXTRA' : '-co APPEND_SUBDATASET=YES -co RASTER_TABLE=name_of_layer', 
    'INPUT' : layer_to_add, 
    'NODATA' : None, 
    'OPTIONS' : '', 
    'OUTPUT' : 'existing.gpkg', 
    'TARGET_CRS' : None 
}
processing.run("gdal:translate", params)

For vector layers see the answer from @GermánCarrillo.