Which mapping action is appropriate for incorporating new custom layers in a mapping tool?

Incorporating new custom layers into a mapping tool is best achieved by adding a GeoJSON file. GeoJSON is a lightweight data-interchange format that encodes geographic data structures in a standard format, making it ideal for web mapping applications. It supports various geometric types, including points, line strings, and polygons, allowing for the representation of complex geospatial information.

When using a GeoJSON file, you can easily define the attributes, styles, and interactions for your custom layers within the mapping tool. Many modern mapping libraries (like Leaflet or Mapbox) natively support GeoJSON, making it straightforward to integrate these layers into a map.

In contrast, importing an image file lacks the capability to represent dynamic or interactive spatial data and is more suited for background images or simple overlays. Using a pre-built layer may limit flexibility and customization, as it typically relies on existing layers that may not meet specific requirements. Creating a dynamic map involves more comprehensive setups and usually includes various functionalities that are broader than merely incorporating new layers. Therefore, adding a GeoJSON file is the most effective action to customize layers within a mapping environment.