NMEA-0183 message: DTM

The DTM message identifies the local geodetic datum and datum offsets from a reference datum. This sentence is used to define the datum to which a position location, and geographic locations in subsequent sentences, is referenced.

An example of the DTM message string is:

$GPDTM,W84,,0.0,N,0.0,W,0.0,W84*7D

DTM message fields

Field

Meaning

0

Message ID $GPDTM

1

Local datum code (CCC):

W84 – WGS-84
W72 – WGS-72
S85 – SGS85
P90 – PE90
999 – User-defined
IHO datum code

2

Local datum subdivision code (x)

3

Latitude offset, in minutes (x.x)

4

N/S (x)

5

Longitude offset, in minutes (x.x)

6

E/W (x)

7

Altitude offset, in meters (x.x)

8

Reference datum code (CCC):

W84 – WGS-84
W72 – WGS-72
S85 – SGS85
P90 – PE90

9

Checksum