The population figures come from World Population Review 2026, which publishes municipal population counts for the Netherlands. The city coordinates come from GeoNames, cities15000, under CC BY 4.0. Both datasets were used whole, so the projection is the same for all twenty five cities.
CBS counts differently. CBS works with municipalities as they are administratively drawn, and a municipality can contain several settlements, or a city can spread across municipal boundaries. For the Netherlands that produces a different list and different numbers. We picked one of the two and used it consistently.
The threshold is one hundred thousand inhabitants. That is a choice rather than a given: it yields twenty five cities and keeps the map readable. A lower threshold would yield more cities and a denser picture.
The third column says whether a Turkish-speaking church meets in that city. Rotterdam is the only yes. The twenty four noes are the foundation’s own knowledge, not the result of a survey, which is why the column is headed as far as we know. The accented circle on the map is Rotterdam.
On the map a circle’s area is proportional to population, not its diameter, so a city twice the size gets twice the area. Circles for coastal cities are trimmed by the coastline, which is geographically correct.
