Generate parcels areas from parcel boundaries

Hi! In this blog I describe how you can create proper parcels with polygon geometry in from polylines (parcel boundaries) and points (Parcel point with parcel attributes placed inside parcel boundaries).

polygonized

Since the 1st of januari 2016 a dataset named, BRK (Basis Registratie Kadaster) is available from PDOK. You can download these in GML format for each province and open directly in QGIS.

The BRK holds information on parcels, land areas. Every parcel is registrated with an unique ID at Kadaster, the Dutch Land Registration authority. They also register who owns the parcel of land and the historie of previous owners. De dataset BRK provides a momentary view of the parcels at a recent point in time.

I expected to receive polygons but the BRK included only lines and points. Fortunately, QGIS provides the tools to provide what I want.

The process of converting parcel boundaries with parcel points to parcel polygons includes globally following steps:

1) Read parcels provided in GML and save as Shape
2) Add spatial indexes to shape files
3) Convert parcel boundaries (lines) to areas (polygones)
4) Add attributes from parcel points to areas

1) First Download the dataset BRK of the Flevoland Province from the download webpage:

https://www.pdok.nl/nl/producten/pdok-downloads/basis-registratie-kadaster/kadastrale-kaart

2) In this case, I unpack the downloaded zip-file in folder C:\data\brk\input\ and create the folder C:\data\brk\output for (intermediate) results.

3) Activate the Processing Toolbox from the menu Processing >> Toolbox. Turn rendering of in QGIS (right below in QGIS application window) and switch the interface of processing from Simplified interface to Advanced interface.
Render of and advanced interface

4) load both gml-files Kadastralegrens.gml and Perceel.gml
inlezen_gml

5) Save both GML files loaded to shape-format, in het layer panel you can select a layer and select in het menu Layers >> Save As….¬†Using the Processing Toolbox you can use Convert format (Translate format) [OGR] from the GDAL/OGR group of algorithms. When you double click on the algorithm the dialog opens that can be used to convert to many vector formats.
GDAL_convert

6) Make sure the created shapefiles are opened in QGIS first. To add a spatial index double click on a selected layer which opens the Layer Properties dialog. Use the button [Create spatial index] .
Create Spatial Index

7) To create parcel areas from boundaries, use the Processing Algorithm Polygonize. Search in the Processing Toolbox with “Polygonize”.
grens_naar_vlak

8) This algorithm takes a lot of time! At 40% it seems to stop, but please be patient. Let QGIS do its job.
log_polygonize

9) Now add the attributes of the point layer Perceel.shp to created area layer KadastraalVlak.shp and I saved it to KadastralePercelen.shp.
join_attributes_to_polygon

When you select a parcel using the identify tool you should see following fields.
Eigenschappen Kadastraal Perceel

That’s it.

Regards, Diethard Jansen (GIS-hulp)