epsgCode [java.lang.String]:
international identifier for the base coordinate reference system (CRS) which was used
to build this topography.
e.g.
EPSG:4326 = WGS-84 (lon/lat from GPS systems, used in OpenStreetMap)
EPSG:25832 = ETRS89 / UTM Zone 32N (UTM Zone System) zone 32 contains most of germany.
see
https://de.wikipedia.org/wiki/European_Petroleum_Survey_Group_Geodesy#EPSG-Codes
https://de.wikipedia.org/wiki/UTM-Koordinatensystem#Aufbau
for references