MultilayerSymbol Class

Detailed Description

Multilayer symbols can be returned from feature layers based on web maps, feature services (with Use Advanced Symbology set to true), or mobile map packages. You can programmatically create and change them using the MultilayerPointSymbol, MultilayerPolylineSymbol, and MultilayerPolygonSymbol subclasses. You can also access the layers that comprise the symbol through symbolLayers and modify their properties, such as the color of a multilayer symbol. Some subclasses also expose additional symbol properties.

The symbol layers that comprise the symbol can be of different types. For example, a polyline geometry may be drawn with a MultilayerPolylineSymbol that has line (stroke) symbol layers that draw the line geometry, and also point (marker) symbol layers that are drawn at specified point locations relative to the line geometry.

When you save an ArcGIS Pro map as a web map, any multilayer symbols in the map are 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, however, both the original symbols and the simplified symbols are stored. The stored symbols allow 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. Symbols used by web scenes are also multilayer but use a different symbol specification than ArcGIS Pro and this API. When you read symbols from a web scene in your app, you get a representation of the multilayer symbol.

If you create a multilayer symbol from a collection of SymbolLayer objects, the first symbol layer in the collection will be drawn first, with the second symbol layer on top of the first, and so on. Note that symbol layers in a multilayer symbol are in reverse order of how they appear in the JSON representation.

// in this multilayer symbol pseudocode json, the 'symbolLayers' ordered list of symbol
// layers contains a solid stroke symbol layer followed by a solid fill symbol layer.
{ "symbolLayers": [{"type": "CIMSolidStroke", "color": "black"},{"type": "CIMSolidFill", "color": "red"}],"type": "CIMPointSymbol" }

// this is the solid fill symbol layer, the reverse order from the json representation
auto* symbolLayerIndexZero = multilayerSymbol->symboLayers()->at(0); // red fill in the image below

// this is the solid stroke symbol layer, the reverse order from the json representation
auto* symbolLayerIndexOne = multilayerSymbol->symboLayers()->at(1); // black outline in the image below

Multilayer symbol consisting of two layers.

Relevant samples:

• Apply unique values with alternate symbols: Apply a unique value with alternate symbols at different scales.