proj4 = '+proj=cass +lat_0=52.4186482777778 +lon_0=13.6272036666667 +x_0=40000 +y_0=10000 +ellps=bessel +nadgrids=BETA2007.gsb +units=m +no_defs +type=crs'
m = Map(256,256,proj4)
lyr = Layer('Name',proj4)