Available data
There are a large number of datasets publicly available. Some are created by the Dutch government and available under permissive licenses. For official purposes, their use is even required. These datasets are mostly maintained by the Dutch Kadaster, and available via the PDOK website (www.pdok.nl). Also, the Dutch bureau for statistics (CBS) publishes some data there. Below, I list the datasets we chose to base our urban dataset on. I also list some datasets with which I have some experience, or which I believe are of good quality, but did not use for our project.
AHN2
website: http://www.ahn.nl/wat_is_het_ahn
Height map of the Netherlands, 50cm resolution. Available as point cloud, or gridded. The AHN2 is now open data
OHN
website: geodesk Wageningen University / Alterra
Derived of the AHN2 datasets, this datasets contains 3 layers: elevation, object height above elevation, and total height (ie. elevation + total height). Useful for finding the height of objects like buildings, trees etc. Data is available for AHN2 users, via the geodesk of the WUR.
TOP10NL (Kadaster)
website: TOP10NL
Description of the infrastructural and built-up Netherlands, in vector format. Also available as raster on several levels of detail. Contains all buildings, roads, rivers, etc. and gives a land-use indication. Accuracy in the order of centimeters. Official format is GML (xml extended with GIS attributes) and is freely available via pdok (see below). Is used in the Summer in the City project, and a DVD from autumn 2013 is available.
Buurt en Wijk
website: nationaalgeoregister
Geometry of all local municipalities 'gemeenten' and neighborhoods 'buurten' of the Netherlands. Additional demographics from CBS are included.
Digitale Kleuren Luchtfoto Nederland 2008
website: (DKLN2008), Copyright Eurosense B.V.,2008
Aerial photos of the Netherlands, in full color (RGB) and infrared. Taken mostly during summer, in the same year (2006?). There are some areas taken later in the year, with notably lower NDVI. However, because of the ndvi does not drop below the cut-off used, the effect on the urban fraction map is minimal.
Links to additional datasets
Those datasets were considered, but not used for various reasons (match with other dataset, availability, actuality, provenance, ...).
Freely available data
BAG, Kadaster. website Basisregistraties adressen en gebouwen. Comparable to the TOP10NL, but now with a focus on addresses and building usage.
Openstreetmap Openstreetmap.org Crowd-sourced map of the world. More up-to-date than many of the official datasets. No guanrantee about quality, but can be similar or better.. Download the Netherlands here
Publieke dienstverlening op de Kaart. Portal to governmental GIS datasets (Kadaster, CBS, etc.) http://www.pdok.nl
Another geoportal listing (Dutch) geographic datasets.http://nationaalgeoregister.nl/
The INSPIRE directive aims to create a European Union (EU) spatial data infrastructure. This will enable the sharing of environmental spatial information among public sector organisations and better facilitate public access to spatial information across Europe. http://inspire-geoportal.ec.europa.eu/
Mostly global data, including climate and agricultural data. http://www.diva-gis.org/Data
Data Archiving and Networked Services (DANS) project. Includes humanities and social sciences. https://easy.dans.knaw.nl/ui/home
The name says it all: a list of GIS data sets. http://en.wikipedia.org/wiki/List_of_GIS_data_sources
Global data useful for biological, ecological and epidemiological research. http://www.edenextdata.com/
Opensource network for geo-data portals. Lists a few national websites created with their framework. http://geonetwork-opensource.org
University Websites
Geodesk of Wageningen University http://www.geodesk.nl
Geodesk of Radboud University http://www.ru.nl/gisdesk/geo-data/algemeen_beschikbaar
Stanford University Gis website with detailed information for the USA. http://lib.stanford.edu/gis
Commercial companies
geo-ICT consultant. Offers some datasets (f.i. car driving times matrices from A to B for Europe) http://www.geodan.nl
This company digitalizes aerial photos and historical kadaster data. http://www.dotkadata.com/
Offers stereo maps based on BAG / BGT kadaster data. http://www.imagem.nl/