The GeoSym symbology offers support for the visualization of the Digital Nautical Chart (DNC) product, which is a VPF-based alternative for the ECDIS S-57/S-52 hydrographic displaying system. In the symbolization of certain hydrographic features on ECDIS systems, the representation of symbols varies based on attributes that are not present within the VPF data structure. To cover those variations, global attributes called "ECDIS external attributes" were defined, in addition to the attributes found in each VPF feature.

You can set the values for those attributes through the API, using the TLcdVPFGeoSymDefaults class. The following table gives an overview of the ECDIS attributes and their usage. A full description of the attributes can be found in the DoD military handbook MIL-HDBK-857, 17 June 2004, paragraph 6.4.1.1.

Table 1. The ECDIS External Attributes
Attribute Description Configuration Default value

ISDM

Interactive Shallow Display Mode

setIDSMValue(Integer)

1

IDSM

Interactive Display Selection Mode

setIDSMValue(Integer)

0

SSDC

Ship’s Safety Depth Contour

setSSDCValue(Float)

50

MSDC

Mariner Specified Deep Contour

setMSDCValue(Float)

100

MSSC

Mariner Sepecified Shallow Contour

setMSSCValue(Float)

10