Symbol

A base class to represent symbols. A symbol defines display properties for features and graphics (collectively referred to as geoelements). A geoelement has a geometry (location and shape), and optional descriptive information. For features and graphics to appear on a map, they must be assigned a symbol.

There are two models for defining symbols in your map: simple and advanced (multilayer). In general, simple symbols are single-layer symbols that provide basic representations, such as marker, line, fill, text, or picture. Advanced symbols are composed of one or several layers that can be defined individually and combined to create complex representations.

Both of these are more fully described as follows:

• Simple symbols follow the web map specification and you work with them through the simple symbol classes. These are also the symbols you get from web maps or from feature services when advanced symbology is turned off. Simple symbols can be created for points (marker symbols), lines (line symbols), and polygons (fill symbols). Each of the simple symbol types provides an enumeration of pre-defined styles that can be applied to the symbol.

• Advanced symbols, accessed through multilayer symbol classes, follow the ArcGIS Pro symbol model. These symbols come from feature services (that use advanced symbology), mobile style files, the dictionary renderer, and mobile map packages. You can also build your own advanced symbols for points, lines, and polygons.

Simple symbology is the symbology of the web map. When authoring maps in ArcGIS Pro as web maps, your multilayer symbols will be converted to simple symbols. In general, point symbols are converted to picture marker symbols optimized for the web, and line and polygon symbols are simplified while representing the original symbol as closely as possible. If you're authoring a feature service from ArcGIS Pro or ArcGIS Desktop, however, both the original symbols and the simplified symbols are stored. This allows clients that support advanced symbols to render the features as originally symbolized, while those that do not support advanced symbols (such as ArcGIS Online Map Viewer) can use the simple symbols for display. Having both sets of symbols allows you to retain the advanced symbology where available and still share the feature service as widely as possible.

If your app works primarily with web maps that you want to look the same throughout the platform, your app should use the simple symbols API. Otherwise, make sure your users understand that advanced symbols render slightly differently on clients that don't support advanced symbology.

If your maps are used only with this API and ArcGIS Pro, you can use advanced symbols exclusively. When rendered by this API, advanced symbols are vectorized. This allows them to scale better on devices with high resolution screens.

You can set LoadSettings.getUseAdvancedSymbology() to control whether the map uses advanced symbols (when available) or always renders with simple symbols.