INTERNATIONAL HYDROGRAPHIC REVIEW
MAY 2020
78
In the Baltic Sea regions of Denmark, a reference level close to the national height system
DVR90 is already being used as chart datum, which can now be considered as a national realiza
tion of the BSCD2000. This means that for a user in Denmark nothing changes and the official
national geoid model can still be used at sea.
Likewise, chart datum and MSL observations in Germany have traditionally been linked to the na
tional height system. In 2016, the previous realization DHHN92 was replaced by DHHN2016.
Both old and new realization are consistent with the EVRS, and the differences between the two
are small and well within the specifications of the BSCD2000. Germany is now in the process to
formally adopt BSCD2000 DHHN2 ° 16 as the chart datum name in its Baltic Sea products, yet without
actual changes for the user.
In Norwegian waters, on southern Skagerrak, a reference 20 cm below Lowest Astronomical Tide
(LAT) is used as chart datum.
On the eastern side of the Baltic, in Estonia, Latvia, Lithuania and Poland, the transition from
Kronstadt-based datums into the new system has come a long way, even if the old and new refer
ence systems will be working in parallel for many more years to come. The transition into the new
system for the paper charts will take longest time to change.
Table 1: Differences between EVRF2019 (zero-tide) and EVRS-compatible national height reference
frames in mm.
Country
Mean
Std. dev.
Min.
Max.
Denmark
+1
6
-12
+ 13
Estonia
-7
8
-22
+ 16
Finland
-3
2
-11
+0
Germany north of 53.5° latitude
-1
4
-8
+ 12
Latvia
-3
2
-12
+6
Lithuania
-4
5
-11
+5
Norway south of 60.0° latitude
-14
7
-42
+3
Sweden
-7
3
-19
-2