EPSG codes: 3398, 3399
AdV codes:  DE_RD-83_3GK4, DE_RD-83_3GK5

Note: in EPSG and AdV codes also format descriptions for 
coordinate data sets are included (order of coordinate 
values,  zone number)  - may be defined differently  

CRS-EU description encloses all zones 4...5, GK_3 
indicates width of zone  - 3 degree 

on GIS accuracy identical to DE_DHDN / GK_3 and DE_PD/83 / 
GK_3 

Germany, Rauenberg,
Lat = 52°27'12.021" N,
Lon = 13°22'04.928" E

Germany, used in Federal State Sachsen

- created by 4 parameter ellipsoidial transformation of 
coord. of Datum 42/83, parameters are computed with 106 
identical points between Datum DHDN represent by points of 
old  Reichsdreiecksnetz RDN and Datum 42/83 over the whole 
transformation area of former Germany East  
- central point of former network Reichsdreiecksnetz, 
which was the basis of DHDN / PD/83 / RD/83 was Rauenberg 
in Berlin, this point was destroyed in 1910 and 
substitute by point Potsdam, therefore the aliases 
Rauenberg Datum and Potsdam Datum are known for German 
Datums 
- the abbreviation RD/83 means Rauenberg Datum/83 to have 
a distinction to PD/83 and is the concrete realisation of 
DHDN in Federal State Sachsen

Gauß Krüger Projection

Transverse Mercator Mapping Equations, in Hooijberg, 
Practical Geodesy, 1997, pages 81-84 

special German specification of Transverse Mercator 
Projection in zones of 3°, also known as Gauss Krüger 
System 

0°

central meridian (CM) of each zone
for DE: 6° E, 9° E, 12° E, 15° E in use

0 m

500 000  + (n * 10**6) m, with n...zone number 
e.g. 2 500 000 for zone number 2 (CM = 6° E)

1.0000

3°

n = longitude value of central meridian / 3
for DE: zones 2, 3, 4, 5