from mapnik import Map, Layer
proj4 = '+proj=stere +lat_0=90 +lat_ts=70 +lon_0=-45 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs'
m = Map(256,256,proj4)
lyr = Layer('Name',proj4)