  Much of our knowledge about the solar dynamo is based on sunspot
observations. It is thus desirable to extend the set of positional and
morphological data of sunspots into the past. Gustav Sp\"orer observed in
Germany from Anklam (1861-1873) and Potsdam (1874-1894). He left detailed
prints of sunspot groups, which we digitized and processed to mitigate
artifacts left in the print by the passage of time. After careful geometrical
correction, the sunspot data are now available as synoptic charts for almost
450 solar rotation periods. Individual sunspot positions can thus be precisely
determined and spot areas can be accurately measured using morphological image
processing techniques. These methods also allow us to determine tilt angles of
active regions (Joy's law) and to assess the complexity of an active region.
