Symbology allows you to represent features so they are meaningful to those looking at your map or chart. One way to create symbology is to link field values to symbols and text strings for feature classes.
ArcGIS for Maritime: Charting symbology tools are based on representations, which are the symbols used to represent features and text fields in the display of map text. The calculated representations and text fields use combinations of feature attributes to determine the symbols for particular features within a feature class. The extra fields added to each feature class, which are used to determine how features should be symbolized, can link to attributes from feature classes and stand-alone tables. The links between attributes and symbols, or conditional rules, can be applied to a specific set of features.
For example, you may want to have one symbol for bridges that are above ground and have two lanes and another for bridges that are at ground level and have two lanes. Nautical symbology can be used to ensure such standardized visualization of data and provide management and storage inside the geodatabase.
The symbols and text created as a result of the nautical symbology rules are also stored inside the geodatabase using feature class representations.
When an update is applied to a database, additional columns are added to each feature class or table that participates in nautical symbology. These fields include the following:
- A field that is given the layer and nautical symbology name by default and holds the representation rule number
- An override field associated with the representation to store symbol exception information
- Text string field for labeling features
The Maritime Charting NIS, chart, and ENC schemas are preconfigured with INT1 specification. Since the geodatabases are preconfigured, using the Update tool will not be necessary. When creating national symbology, editing the representation rule, or adding a representation rule on a specific layer, will require the Update tool to be applied to the geodatabase. In a multiuser environment, where some users are restricted from making schema changes, it is recommended that an administrator run this tool with the appropriate symbology first.
Calculate (selected set)
The Calculate (selected set) tool assigns symbology and text fields only for selected features. It uses attributes to determine the way features are symbolized. The representations are grouped based on INT1 or national symbology.
The Calculate (all) tool is the same as the Calculate (selected set) tool in that it assigns symbology and text fields. This tool will calculate layers highlighted in the Table Of Contents window. The number of highlighted layers can be as few as one layer or as many as all layers.
The Nautical Symbology Properties tool calculates depth tints and safety contour representations in the DepthsA and DepthsL feature classes. Changing the property values will modify the extent of the blue tint and safety contour limit of the entire chart.
Views are map settings that can be saved to and retrieved from any geodatabase. They allow you to manage the properties of a data frame and layers so they can be reapplied at any time while allowing you to decide which current map properties to keep and which to override.
International symbol specifications
There are two symbol specifications included in Maritime Charting: S-52 and INT1. Both specifications are an international standard established by the International Hydrographic Organization (IHO).
S-52 is the color and symbol specification for display of Electronic Navigation Charts (ENC) in an Electronic Chart Display and Information System (ECDIS).
INT1 is a supplementary reference within the IHO S-4 publication and references the internationally agreed-on product specification for symbols, abbreviations, and terms used on hard-copy navigational charts.
National symbol specifications
National symbology is a customized symbol specification. The nautical charts produced around the world have a distinctive look that is unique to each hydrographic office producing them because each hydrographic office uses its own variation of the INT1 symbols.