Most nations warehouse a treasure trove of historic aerial photography and maps that provide the foundation for tracking significant changes over time. In addition to providing a historical perspective on land and development changes, this data is also very relevant for citizens who want to see how their places of residence have changed over time.
In the Netherlands, Dotka Data maintains a large and growing collection of historical aerial photography and maps, reflecting more than 200 years of history. The collection includes topographic maps from as far back as 1798, and aerial photographs taken for topological purposes from 1932 to current day.