Feature Description
Feature attributes describe the characteristics of a feature. Editing object properties is a crucial step to ensure chart production complies with standards and enhances navigation safety and accuracy. After drawing a feature, you need to assign corresponding attribute values. Attributes vary among different feature types. The S-57 feature attribute dictionary contains descriptions from S-57 Standard Appendix A, including attribute names, codes, types, expected input values, etc.
Steps
In an editable chart group, select one or more features, right-click and choose Properties to open the right-side properties panel. The panel includes:
- Object Info: Displays basic info (e.g., name, record ID) and attribute information (e.g., property abbreviation, attribute name, attribute value). You can modify Attribute Value here.
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Reference Object: In chart data, a graphical feature is often composed of multiple basic geometric components (point-chain structure), collectively called "reference objects". When selecting a feature, its properties include underlying geometry info through reference objects. These are defined and controlled by Object ID, Boundary Direction, Boundary Type, and Mask Type to manage geometry and display effects. Selected objects in the list will be automatically located and highlighted on the map.
- Object ID: A unique identifier for each reference object, formed by concatenating two subfields (RCNM and RCID) of the vector record identifier (VRID). RCNM (2 characters) distinguishes spatial object types: "VI" for isolated nodes, "VC" for connected nodes, "VE" for edges. RCID is a 10-digit numeric value.
- Boundary Direction: Defines how a feature references linear spatial object directions. Options: Forward (aligned with node sequence), Reverse (opposite to node sequence), Direction Independent.
- Boundary Type: Specifies the reference edge type: Outer Border or Internal Border.
- Mask Type: Controls reference object visibility in symbolic displays. Options: Shield, Show, Nothing to do with mask.
Shield mask hides or suppresses certain geographic elements to avoid visual clutter. For example, a fairway feature composed of multiple polygons may display discontinuities. Setting boundary edges to Shield ensures seamless rendering.
- Settings: Configures attributes like horizontal datum (HORDAT), positional accuracy (POSACC), and position quality (QUAPOS).
- Node: Details of nodes constituting the feature object, including:
- Object: Shows selected object type, total sub-objects, current sub-object, and total nodes.
- Node Information: Displays nodes of the current sub-object in a table. Each record corresponds to a node with coordinate info (in degrees). Supports adding, inserting, deleting nodes, and exporting to CSV.
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