This chapter lists various cases/projects where Stetl is used.


NLExtract is a development project that aims to provide ETL-tooling for all Dutch Open Geo-Datasets, in particular the country wide “Key Registries” (Dutch: Basisregistraties) like Cadastral Parcels (BRK), Topography (BRT+BGT) and Buildings and Addresses (BAG). These datasets are provided as XML/GML. The ETL mostly provides a transformation to PostGIS. For all Key Registries, except for the BAG, Stetl is used, basically as-is, without extra (Python) programming. See also the NLExtract GitHub:

Adresses and Buildings (BAG v2)

BAG version 1 ETL was developed as a custom Python program. In 2021 Dutch Kadaster released BAG version 2. For NLExtract a moment to switch ETL for BAG to Stetl. In particular use is made of the recent (v3.2.1+) GDAL/OGR LVBAG Driver and Python bindings for GDAL VSI /vsizip file handling.

See and the Stetl conf at

Topography (BRT)

Includes ETL for 5 scale levels: TOP10NL through TOP1000NL.

See and the Stetl conf at e.g.

Detailed Topography (BGT)

This is a very large and heavy dataset based on CityGML. Stetl streaming ETL is here at its best.

See and the Stetl conf at


These were the origins of Stetl. This project was sponsored by Kadaster. See The ETL involved the transformation of Dutch Key Registries (see above) to harmonized INSPIRE GML according to the Annexes.


BAG to INSPIRE Addresses Annex II Theme.


Ordnance Survey

A successful Proof-of-Concept to convert Ordnance Survey Mastermap GML to PostGIS:


A SensorWeb project by Geonovum, see

Dutch AQ to WFS/WMS(-Time) and SOS

Stetl was used for ETL from Dutch Air Quality Data from RIVM (XML) to WMS(-Time), WFS and SOS. The latter was effected by SOS-Transactional publication. Documentation at and ETL on GitHub at

Dutch AQ to EAI Reporting

Stetl was used to generate XML-based reports for the EU EAI:

This involved the first use of Jinja2 templating for complex XML/GML generation.

Smart Emission

Sensors for air quality, meteo and audio at civilians. Project by University of Nijmegen/Gemeente Nijmegen with participation by Geonovum. Stetl is used to transform a low-level sensor API to PostGIS and later on WMS/WFS/SOS and the SensorThings API. Also InfluxDB output is developed here.

This is also an example how to use a Stetl Docker image: