Feature layer (geodatabase)

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Display features from a local geodatabase.

Feature layer (geodatabase)

Use case

Accessing data from a local geodatabase is useful when working in an environment that has an inconsistent internet connection or that does not have an internet connection at all. For example, a department of transportation field worker might source map data from a local geodatabase when conducting signage inspections in rural areas with poor network coverage.

How to use the sample

Pan and zoom around the map. View the data loaded from the geodatabase.

How it works

  1. Create an AGSGeodatabase using the provided local resource, LA_Trails.
  2. Use AGSGeodatabase.load(completion:) to load the geodatabase.
  3. Get the AGSGeodatabaseFeatureTable with the name Trailheads from the geodatabase, AGSGeodatabase.geodatabaseFeatureTable(withName:).
  4. Create an AGSFeatureLayer using the table from above.
  5. Add the feature layer to the map's array of operationalLayers.

Relevant API

  • AGSFeatureLayer
  • AGSGeodatabase
  • AGSGeodatabaseFeatureTable

Offline data

This sample uses the Los Angeles Vector Tile Package and Los Angeles Trailheads geodatabase. Both are downloaded from ArcGIS Online automatically.

About the data

The sample shows trailheads in the greater Los Angeles area displayed on top of a vector tile basemap.

Additional information

One of the ArcGIS Runtime data set types that can be accessed via the local storage of the device (i.e. hard drive, flash drive, micro SD card, USB stick, etc.) is a mobile geodatabase. A mobile geodatabase can be provisioned for use in an ArcGIS Runtime application by ArcMap. The following provide some helpful tips on how to create a mobile geodatabase file:

In ArcMap, choose File > Share As > ArcGIS Runtime Content from the menu items to create the .geodatabase file (see the Creating ArcGIS Runtime content) document.

Note: You could also use the 'Services Pattern' and access the AGSGeodatabase class via a Feature Service served up via ArcGIS Online or ArcGIS Enterprise. Instead of using AGSGeodatabase to access the .geodatabase file on disk, you would use AGSGeodatabaseSyncTask to load a geodatabase from a URL instead.

Tags

geodatabase, mobile, offline

Sample Code

FeatureLayerGDBViewController.swift
                                                  
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// Copyright 2016 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

class FeatureLayerGDBViewController: UIViewController {
    @IBOutlet var mapView: AGSMapView!

    private var geodatabase: AGSGeodatabase!

    override func viewDidLoad() {
        super.viewDidLoad()

        // add the source code button item to the right of navigation bar
        (self.navigationItem.rightBarButtonItem as! SourceCodeBarButtonItem).filenames = ["FeatureLayerGDBViewController"]

        // instantiate map with basemap
        let map = AGSMap(basemapStyle: .arcGISImagery)

        // assign map to the map view
        mapView.map = map
        mapView.setViewpoint(AGSViewpoint(center: AGSPoint(x: -13214155, y: 4040194, spatialReference: .webMercator()), scale: 35e4))

        // instantiate geodatabase with name
        self.geodatabase = AGSGeodatabase(name: "LA_Trails")

        // load the geodatabase for feature tables
        self.geodatabase.load { [weak self] (error: Error?) in
            if let error = error {
                self?.presentAlert(error: error)
            } else {
                let featureTable = self!.geodatabase.geodatabaseFeatureTable(withName: "Trailheads")!
                let featureLayer = AGSFeatureLayer(featureTable: featureTable)
                self?.mapView.map?.operationalLayers.add(featureLayer)
            }
        }
    }
}

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