I just found Schroetter's map of East Prussia on a Polish library site.

Schroetter's work on this map was performed during 1796 though 1802.

Von Boyen specifically mentions the use of Schroetter's map by the Russian generals during the 1807 campaign in Poland. Evidence from the French side suggests they used it as well.

With name changes and the events of history over the years, such detailed maps were important for our efforts.

For those interested this "Karte von Ost-Preussen nebst Preussisch Litthauen und West-Preussen nebst dem Netzdistrict" is based on the original work, although it appears to be an 1809 copy.

It is in djvu format and can be downloaded in a zip file. (I prefer to work with other formats, such as jpg, so I export them from the djvu file - easily done after downloading)

The sections can be electronically zoomed and the image retains clarity very well.

In working on Napoleon's Triumph, James Arnold and I used photocopies obtained through the Univesity of Basel's library of an 1804 copy (and a later 1810 map by Streit). I wish this version had been available earlier to save squinting and tedious sessions with a magnifying glass. - R.