BasemapGallery

BasemapGallery

The BasemapGallery displays a collection of basemaps from ArcGIS Online, a user-defined portal, or an array of BasemapGalleryItems. When a new basemap is selected from the BasemapGallery and the optional BasemapGalleryViewModel.geoModel property is set, the basemap of the geoModel is replaced with the basemap in the gallery.

iPhone	iPad

NOTE: BasemapGallery uses metered ArcGIS basemaps by default, so you will need to configure an API key. See Security and authentication documentation for more information.

Features

BasemapGallery:

• Can be configured to use a list, grid, or automatic layout. When using an automatic layout, list or grid presentation is chosen based on the horizontal size class of the display.
• Displays basemaps from a portal or a custom collection. If neither a custom portal or array of basemaps is provided, the list of basemaps will be loaded from ArcGIS Online.
• Displays a representation of the map or scene's current basemap if that basemap exists in the gallery.
• Displays a name and thumbnail for each basemap.
• Can be configured to automatically change the basemap of a geo model based on user selection.

Key properties

BasemapGallery has the following initializers:

    /// Creates a `BasemapGallery` with the given geo model and array of basemap gallery items.
    /// - Remark: If `items` is empty, ArcGIS Online's developer basemaps will
    /// be loaded and added to `items`.
    /// - Parameters:
    ///   - items: A list of pre-defined base maps to display.
    ///   - geoModel: A geo model.
    public init(items: [BasemapGalleryItem] = [], geoModel: GeoModel? = nil)

    /// Creates a `BasemapGallery` with the given geo model and portal.
    /// The portal will be used to retrieve basemaps.
    /// - Parameters:
    ///   - portal: The portal to use to load basemaps.
    ///   - geoModel: A geo model.
    public init(portal: Portal, geoModel: GeoModel? = nil)

BasemapGallery has the following instance method:

• style(_ newStyle: Style) - The Style of the BasemapGallery, used to specify how the list of basemaps is displayed (list, grid, or automatic depending on display width).

BasemapGallery has the following helper class and initializer:

///  The `BasemapGalleryItem` encompasses an element in a `BasemapGallery`.
public class BasemapGalleryItem : ObservableObject

/// Creates a `BasemapGalleryItem`.
/// - Parameters:
///   - basemap: The `Basemap` represented by the item.
///   - name: The item name. If `nil`, `Basemap.name` is used, if available.
///   - description: The item description. If `nil`, `Basemap.Item.description`
///   is used, if available.
///   - thumbnail: The thumbnail used to represent the item. If `nil`,
///   `Basemap.Item.thumbnail` is used, if available.
public init(
    basemap: Basemap,
    name: String? = nil,
    description: String? = nil,
    thumbnail: UIImage? = nil
)

Behavior:

Selecting a basemap with a spatial reference that does not match that of the geo model will display an error. It will also display an error if a provided base map cannot be loaded. If a GeoModel is provided to the BasemapGallery, selecting an item in the gallery will set that basemap on the geo model.

Usage

Basic usage for displaying a BasemapGallery.

@StateObject var map = Map(basemapStyle: .arcGISImagery)

var body: some View {
    MapView(map: map)
        .overlay(alignment: .topTrailing) {
            BasemapGallery(geoModel: map)
                .style(.automatic())
                .padding()
        }
}

To see it in action, try out the Examples and refer to BasemapGalleryExampleView.swift in the project.