Annotation is useful for displaying text that you don't want to move or resize when the map is panned or zoomed (unlike labels which will move and resize). You can use annotation to place text at a fixed size, position, orientation, font, and so on. You may choose to do this for cartographic reasons or because the exact placement of the text is important.
How to use the sample
Pan and zoom to see names of waters and burns in a small region of Scotland.
How it works
Create an AGSMap with a light gray canvas and a viewpoint near the data.
Create an AGSFeatureLayer from a feature service URL.
Create an AGSAnnotationLayer from a feature layer URL.
Add both layers to the operational layers of the map and add it to an AGSMapView.
The annotation layer contains two sublayers of rivers in East Lothian, Scotland, which were set by the author to only be visible within the following scale ranges:
Water (1:50,000 - 1:100,000) - A large stream, as defined in the Scots language
Burn (1:25,000 - 1:75,000) - A brook or small stream, as defined in the Scots language
Additional information
Annotation is only supported from feature services hosted on an ArcGIS Enterprise server.
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// Copyright 2020 Esri.//// Licensed under the Apache License, Version 2.0 (the "License");// you may not use this file except in compliance with the License.// You may obtain a copy of the License at//// http://www.apache.org/licenses/LICENSE-2.0//// Unless required by applicable law or agreed to in writing, software// distributed under the License is distributed on an "AS IS" BASIS,// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.// See the License for the specific language governing permissions and// limitations under the License.import UIKit
import ArcGIS
classDisplayAnnotationViewController: UIViewController{
@IBOutletprivateweakvar mapView: AGSMapView! {
didSet {
// Assign the map to the map view. mapView.map = makeMap()
mapView.setViewpoint(AGSViewpoint(latitude: 55.882436, longitude: -2.725610, scale: 72223.819286))
}
}
funcmakeMap() -> AGSMap {
let map =AGSMap(basemapStyle: .arcGISLightGray)
// Create a feature layer.let featureServiceURL =URL(string: "https://services1.arcgis.com/6677msI40mnLuuLr/arcgis/rest/services/East_Lothian_Rivers/FeatureServer/0")!let featureTable =AGSServiceFeatureTable(url: featureServiceURL)
let riverFeatureLayer =AGSFeatureLayer(featureTable: featureTable)
// Create an annotation layer.let riverFeatureLayerURL =URL(string: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/RiversAnnotation/FeatureServer/0")!let annotationLayer =AGSAnnotationLayer(url: riverFeatureLayerURL)
// Add both layers to the operational layers. map.operationalLayers.add(riverFeatureLayer)
map.operationalLayers.add(annotationLayer)
return map
}
overridefuncviewDidLoad() {
super.viewDidLoad()
// Add the source code button item to the right of navigation bar. (self.navigationItem.rightBarButtonItem as!SourceCodeBarButtonItem).filenames = ["DisplayAnnotationViewController"]
}
}
