The app is based on the maps from
Johann Marius Friedrich Schmidt,
Historischer Atlas von Berlin, in VI Grundrissen nach gleichem Maasstabe; von 1415 bis 1800.
(Historical Atlas of Berlin, in VI ground plots at the same scale; 1415 to 1800.)
Published by Simon Schropp & Comp., Berlin 1835.
This atlas consists of maps that illustrate Berlin in the years 1415, 1648, 1688, 1720, 1740 and 1802.
The historical maps can be used offline, i.e. without an internet connection.
A today's map (the OpenStreetMap) can be displayed to compare the six maps of the atlas with the present situation.
If you are inside the area of the historical atlas the app determines your location and shows it on the map.
With 'Berlin 1415 - 1802 pro' you enjoy a completely ad-free version of the app and support the development of this and other projects.