The visualization of S-101 Electronic Navigational Charts (ENC) is governed by specific components mandated within the S-101 Product Specification. The standards themselves are defined and maintained by the International Hydrographic Organization (IHO) and its associated working groups. The specification defines a number of settings the user can control for customizing the display of S-101 ENCs.

The table below summarizes the key display settings available for S-101 data visualization :

Setting Description

Display mode

Controls the display mode for the chart, determining which feature categories and viewing group layers are visible. Three modes are available:

  • DISPLAY BASE: shows only essential features that must always be displayed, such as coastlines, safety contours, traffic separation schemes.

  • STANDARD: the ECDIS default display mode. Includes all Display Base layers and more navigation-critical features such as aids to navigation (buoys, beacons, lights), boundaries and limits, prohibited/restricted areas, routing systems, and cautionary notes.

  • OTHER (All Information): displays all available information in the System Electronic Navigational Chart. Includes everything from Standard Display plus supplementary features like spot soundings, submarine cables/pipelines, isolated dangers, magnetic variation, depth contours, seabed information, and tidal data.

Color palette

Specifies the color scheme used for rendering: Day, Dusk, or Night modes. Affects visibility under different lighting conditions.

Safety contour

Depth value (in meters) that defines the safety contour line. Areas shallower than this value are highlighted as potentially hazardous.

Deep contour

Depth value (in meters) that defines the deep contour line. Areas deeper than this value are rendered differently for navigation purposes.

Display planes

Controls which display planes are active for rendering chart features relative to radar imagery. Display planes determine the layering order of chart content in ECDIS systems, allowing features to be positioned either above or below the radar display. Two planes are available:

  • OVER RADAR: features appear on top of the radar image, ensuring critical navigational information — such as hazards, aids to navigation, and restricted areas — remains visible when the radar overlay is active. This prevents important chart data from being obscured by radar returns.

  • UNDER RADAR: features appear underneath the radar image, allowing radar returns to take visual precedence while maintaining chart context in the background. Useful for less critical chart information.

Multiple display planes can be active simultaneously, providing flexible control over which feature categories appear above or below radar imagery based on their navigational importance.

Safety depth

Depth value (in meters) below which soundings are emphasized. Used to identify safe water depths for vessel navigation.

Shallow contour

Depth value (in meters) that defines the shallow contour line. Distinguishes shallow areas from deeper waters.

Shallow water dangers

Boolean flag to enable and disable highlighting of dangers in shallow water areas for enhanced safety awareness.

Plain boundaries

Boolean flag to toggle between plain or symbolized boundaries for areas and zones on the chart.

Use two shades

Boolean flag to enable two-color shading for depth areas instead of multiple color gradations.

Full light lines

Boolean flag to control whether light sector lines are shown in full or simplified representation.

Simplified symbols

Boolean flag to use simplified symbols for features instead of detailed paper-chart symbols.

Display overscale indication

Boolean flag to show visual indication when the chart is displayed at a larger scale than recommended.

Display underscale indication

Boolean flag to show visual indication when the chart is displayed at a smaller scale than recommended.

Ignore Scale minimum

Boolean flag to bypass minimum scale restrictions and display chart data regardless of zoom level.

Underscale indication color

Color used to highlight areas when the chart is displayed below its recommended scale.

Radar overlay

Boolean flag to enable radar overlay mode, which adjusts colors and styling for integration with radar displays.

Language

String value specifying the preferred language for rendering texts on the chart.

Viewing group layer

Specifies which S-101 viewing group layers are visible on the chart. Each layer represents a category of chart features:

  • DISPLAY BASE: essential base features, such as coastlines and safety contours

  • DRYING LINE: drying lines indicating areas exposed at low tide

  • BUOYS BEACONS AIDS TO NAVIGATION: navigation aids like buoys and beacons

  • BUOYS BEACONS STRUCTURES: buoys, beacons, and related structures

  • LIGHTS: light features for navigation

  • BOUNDARIES AND LIMITS: area boundaries and limits

  • PROHIBITED AND RESTRICTED AREAS: areas with navigation restrictions

  • CHART SCALE BOUNDARIES: chart scale boundary lines

  • CAUTIONARY NOTES: notes for mariners

  • SHIPS ROUTEING SYSTEMS AND FERRY ROUTES: shipping lanes and ferry routes

  • ARCHIPELAGIC SEA LANES: archipelagic sea lanes

  • MISCELLANEOUS STANDARD: other standard display features

  • SPOT SOUNDINGS: individual depth soundings

  • SUBMARINE CABLES AND PIPELINES: underwater cables and pipelines

  • ALL ISOLATED DANGERS: isolated dangers to navigation

  • MAGNETIC VARIATION: magnetic variation information

  • DEPTH CONTOURS: depth contour lines

  • SEABED: seabed information

  • TIDAL: tidal features

  • MISCELLANEOUS OTHER: other non-standard display features

  • SHALLOW PATTERN: shallow water pattern (mariner selector)

  • ACCURACY: zone of confidence and low accuracy symbols (mariner selector)

  • FEATURE HIGHLIGHTS: toggles feature highlights (mariner selector)

  • HIGHLIGHT INFO: highlights features with amplifying text (mariner selector)

  • HIGHLIGHT DOCUMENT: highlights features linked to documents or images (mariner selector)

  • HIGHLIGHT DATE DEPENDENT: highlights date-dependent features (mariner selector)

  • CONTOUR LABEL: turns on display of contour labels (mariner selector)

  • UPDATE REVIEW: highlights objects modified in the latest update (mariner selector)

  • CHART TEXT: general chart text

  • IMPORTANT TEXT: important text elements

  • OTHER TEXT: other text not classified as important

  • NAMES: geographic names such as anchorages, buoys and bridges

  • LIGHT DESCRIPTION: light description strings

  • ALL OTHER CHART TEXT: all other chart text not controlled via NAMES or LIGHT DESCRIPTION

These settings are available in the TLcdS101DisplaySettings class.

For example to switch to night settings, you use:

s101DisplaySettings.setColorPalette(ELcdS101ColorPalette.NIGHT);
These images show the same S-101 data visualized with day and night settings.
day settings
Figure 1. S-101 data displayed with day settings
night settings
Figure 2. S-101 data displayed with night settings

To apply those settings on your layer, you set them on the layer factory before layer creation.

TLcdS101DisplaySettings s101DisplaySettings = new TLcdS101DisplaySettings();
s101DisplaySettings.setDisplayMode(ELcdS101DisplayMode.STANDARD);
s101DisplaySettings.setSafetyDepth(5.0);
S101GXYLayerFactory layerFactory = new S101GXYLayerFactory();
layerFactory.setDisplaySettings(s101DisplaySettings);
ILcdGXYLayer layer = layerFactory.createGXYLayer(model);

In a typical application, you have a single TLcdS101DisplaySettings instance which is shared by all layers. This ensures that when you, or an application user, changes the display settings, the changes are applied to all layers.

In the sample, you can change the display settings in a UI panel. See the samples.decoder.ecdis.s101.S101DisplaySettingsCustomizer class.