WMS service catalog

View inAndroidFormsUWPWPFWinUIiOSView on GitHub

Connect to a WMS service and show the available layers and sublayers.

Image of WMS service catalog

Use case

WMS services often contain many layers and sublayers. Presenting the layers and sublayers in a UI allows you to explore what is available in the service and add individual layers to a map.

How to use the sample

  1. Open the sample. A hierarchical list of layers and sublayers will appear.
  2. Select a layer to enable it for display. If the layer has any children, the children will also be selected.

How it works

  1. A WmsService is created and loaded.
  2. WmsService has a ServiceInfo property, which is a WmsServiceInfo. WmsServiceInfo has a WmsLayerInfo object for each layer (excluding sublayers) in the LayerInfos collection.
  3. A method is called to recursively discover sublayers for each layer. Layers are wrapped in a view model and added to a list.
    • The view model has a Select method which recursively selects or deselects itself and sublayers.
    • The view model tracks the children and parent of each layer.
  4. Once the layer selection has been updated, another method is called to create a new WmsLayer from a list of selected WmsLayerInfo.

Relevant API

  • WmsLayer(List)
  • WmsLayerInfo
  • WmsService
  • WmsServiceInfo

About the data

This sample shows forecasts guidance warnings from an ArcGIS REST service produced by the U.S. National Weather Service. The map shows fronts, highs, and lows, as well as areas of forecast precipitation.

Tags

catalog, OGC, web map service, WMS

Sample Code

WmsServiceCatalog.cs
Use dark colors for code blocksCopy
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
// Copyright 2017 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.

using System;
using System.Collections.Generic;
using System.Linq;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Ogc;
using Esri.ArcGISRuntime.UI.Controls;
using Foundation;
using UIKit;

namespace ArcGISRuntime.Samples.WmsServiceCatalog
{
    [Register("WmsServiceCatalog")]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "WMS service catalog",
        category: "Layers",
        description: "Connect to a WMS service and show the available layers and sublayers. ",
        instructions: "",
        tags: new[] { "OGC", "WMS", "catalog", "web map service" })]
    public class WmsServiceCatalog : UIViewController
    {
        // Hold references to UI controls.
        private MapView _myMapView;
        private UITableView _layerList;
        private NSLayoutConstraint[] _portraitConstraints;
        private NSLayoutConstraint[] _landscapeConstraints;

        // Hold the URL to the WMS service providing the US NOAA National Weather Service forecast weather chart.
        private readonly Uri _wmsUrl = new Uri("https://idpgis.ncep.noaa.gov/arcgis/services/NWS_Forecasts_Guidance_Warnings/natl_fcst_wx_chart/MapServer/WMSServer?request=GetCapabilities&service=WMS");

        // Hold a source for the UITableView that shows the available WMS layers.
        private LayerListSource _layerListSource;

        public WmsServiceCatalog()
        {
            Title = "WMS service catalog";
        }

        private async void Initialize()
        {
            // Show dark gray canvas basemap.
            _myMapView.Map = new Map(BasemapStyle.ArcGISDarkGray);

            // Create the WMS Service.
            WmsService service = new WmsService(_wmsUrl);

            try
            {
                // Load the WMS Service.
                await service.LoadAsync();

                // Get the service info (metadata) from the service.
                WmsServiceInfo info = service.ServiceInfo;

                List<LayerDisplayVM> viewModelList = new List<LayerDisplayVM>();

                // Get the list of layer infos.
                foreach (var layerInfo in info.LayerInfos)
                {
                    LayerDisplayVM.BuildLayerInfoList(new LayerDisplayVM(layerInfo, null), viewModelList);
                }

                // Construct the layer list source.
                _layerListSource = new LayerListSource(viewModelList, this);

                // Set the source for the table view (layer list).
                _layerList.Source = _layerListSource;

                // Force an update of the list display.
                _layerList.ReloadData();
            }
            catch (Exception e)
            {
                new UIAlertView("Error", e.ToString(), (IUIAlertViewDelegate) null, "OK", null).Show();
            }
        }

        /// <summary>
        /// Updates the map with the latest layer selection.
        /// </summary>
        private async void UpdateMapDisplay(List<LayerDisplayVM> displayList)
        {
            // Remove all existing layers.
            _myMapView.Map.OperationalLayers.Clear();

            // Get a list of selected LayerInfos.
            IEnumerable<WmsLayerInfo> selectedLayers = displayList.Where(vm => vm.IsEnabled).Select(vm => vm.Info);

            // Only WMS layer infos without sub layers can be used to construct a WMS layer. Group layers that have sub layers must be excluded.
            selectedLayers = selectedLayers.Where(info => info.LayerInfos.Count == 0).ToList();

            // Create a new WmsLayer from the selected layers.
            WmsLayer myLayer = new WmsLayer(selectedLayers);

            try
            {
                // Wait for the layer to load.
                await myLayer.LoadAsync();

                // Zoom to the extent of the layer.
                await _myMapView.SetViewpointAsync(new Viewpoint(myLayer.FullExtent));

                // Add the layer to the map.
                _myMapView.Map.OperationalLayers.Add(myLayer);
            }
            catch (Exception e)
            {
                new UIAlertView("Error", e.ToString(), (IUIAlertViewDelegate) null, "OK", null).Show();
            }
        }

        /// <summary>
        /// Takes action once a new layer selection is made.
        /// </summary>
        public void LayerSelectionChanged(int selectedIndex)
        {
            // Clear existing selection.
            foreach (LayerDisplayVM item in _layerListSource.ViewModelList)
            {
                item.Select(false);
            }

            // Update the selection.
            _layerListSource.ViewModelList[selectedIndex].Select();

            // Update the map.
            UpdateMapDisplay(_layerListSource.ViewModelList);
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            Initialize();
        }

        public override void LoadView()
        {
            // Create the views.
            View = new UIView {BackgroundColor = ApplicationTheme.BackgroundColor};

            _myMapView = new MapView();
            _myMapView.TranslatesAutoresizingMaskIntoConstraints = false;

            _layerList = new UITableView();
            _layerList.TranslatesAutoresizingMaskIntoConstraints = false;
            _layerList.RowHeight = 40;

            UILabel helpLabel = new UILabel
            {
                Text = "Select layers for display.",
                AdjustsFontSizeToFitWidth = true,
                TextAlignment = UITextAlignment.Center,
                BackgroundColor = UIColor.FromWhiteAlpha(0, .6f),
                TextColor = UIColor.White,
                Lines = 1,
                TranslatesAutoresizingMaskIntoConstraints = false
            };

            // Add the views.
            View.AddSubviews(_myMapView, _layerList, helpLabel);

            // Lay out the views.
            NSLayoutConstraint.ActivateConstraints(new[]
            {
                helpLabel.LeadingAnchor.ConstraintEqualTo(_myMapView.LeadingAnchor),
                helpLabel.TrailingAnchor.ConstraintEqualTo(_myMapView.TrailingAnchor),
                helpLabel.TopAnchor.ConstraintEqualTo(_myMapView.TopAnchor),
                helpLabel.HeightAnchor.ConstraintEqualTo(40),
            });

            _portraitConstraints = new[]
            {
                _layerList.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                _layerList.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                _layerList.TopAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.TopAnchor),
                _layerList.HeightAnchor.ConstraintEqualTo(_layerList.RowHeight * 4),
                _myMapView.TopAnchor.ConstraintEqualTo(_layerList.BottomAnchor),
                _myMapView.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                _myMapView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                _myMapView.BottomAnchor.ConstraintEqualTo(View.BottomAnchor)
            };

            _landscapeConstraints = new[]
            {
                _layerList.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                _layerList.TopAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.TopAnchor),
                _layerList.BottomAnchor.ConstraintEqualTo(View.BottomAnchor),
                _layerList.TrailingAnchor.ConstraintEqualTo(View.CenterXAnchor),
                _myMapView.LeadingAnchor.ConstraintEqualTo(_layerList.TrailingAnchor),
                _myMapView.TopAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.TopAnchor),
                _myMapView.BottomAnchor.ConstraintEqualTo(View.BottomAnchor),
                _myMapView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor)
            };

            SetLayoutOrientation();
        }

        public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
        {
            base.TraitCollectionDidChange(previousTraitCollection);

            // Reset constraints.
            NSLayoutConstraint.DeactivateConstraints(_portraitConstraints);
            NSLayoutConstraint.DeactivateConstraints(_landscapeConstraints);
            SetLayoutOrientation();
        }

        private void SetLayoutOrientation()
        {
            if (View.TraitCollection.VerticalSizeClass == UIUserInterfaceSizeClass.Compact)
            {
                NSLayoutConstraint.ActivateConstraints(_landscapeConstraints);
            }
            else
            {
                NSLayoutConstraint.ActivateConstraints(_portraitConstraints);
            }
        }
    }

    /// <summary>
    /// This is a ViewModel class for maintaining the state of a layer selection.
    /// Typically, this would go in a separate file, but it is included here for clarity.
    /// </summary>
    public class LayerDisplayVM
    {
        public WmsLayerInfo Info { get; }

        // True if layer is selected for display.
        public bool IsEnabled { get; private set; }

        // Keeps track of how much indentation should be added (to simulate a tree view in a list).
        private int NestLevel
        {
            get
            {
                if (Parent == null)
                {
                    return 0;
                }

                return Parent.NestLevel + 1;
            }
        }

        private List<LayerDisplayVM> Children { get; set; }

        private LayerDisplayVM Parent { get; }

        public LayerDisplayVM(WmsLayerInfo info, LayerDisplayVM parent)
        {
            Info = info;
            Parent = parent;
        }

        // Select this layer and all child layers.
        public void Select(bool isSelected = true)
        {
            IsEnabled = isSelected;
            if (Children == null)
            {
                return;
            }

            foreach (var child in Children)
            {
                child.Select(isSelected);
            }
        }

        // Name with formatting to simulate treeview.
        public string Name => $"{new string(' ', NestLevel * 8)} {Info.Title}";

        public static void BuildLayerInfoList(LayerDisplayVM root, IList<LayerDisplayVM> result)
        {
            // Add the root node to the result list.
            result.Add(root);

            // Initialize the child collection for the root.
            root.Children = new List<LayerDisplayVM>();

            // Recursively add sublayers.
            foreach (WmsLayerInfo layer in root.Info.LayerInfos)
            {
                // Create the view model for the sublayer.
                LayerDisplayVM layerVM = new LayerDisplayVM(layer, root);

                // Add the sublayer to the root's sublayer collection.
                root.Children.Add(layerVM);

                // Recursively add children.
                BuildLayerInfoList(layerVM, result);
            }
        }
    }

    /// <summary>
    /// Class defines how a UITableView renders its contents.
    /// This implements the list of WMS sublayers.
    /// </summary>
    public class LayerListSource : UITableViewSource
    {
        public readonly List<LayerDisplayVM> ViewModelList = new List<LayerDisplayVM>();

        // Used when re-using cells to ensure that a cell of the right type is used
        private const string CellId = "TableCell";

        // Hold a reference to the owning view controller; this will be the active instance of WmsServiceCatalog.
        [Weak] public WmsServiceCatalog Owner;

        public LayerListSource(List<LayerDisplayVM> items, WmsServiceCatalog owner)
        {
            // Set the items.
            if (items != null)
            {
                ViewModelList = items;
            }

            // Set the owner.
            Owner = owner;
        }

        /// <summary>
        /// This method gets a table view cell for the suggestion at the specified index.
        /// </summary>
        public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
        {
            // Try to get a re-usable cell (this is for performance).
            UITableViewCell cell = tableView.DequeueReusableCell(CellId);

            // If there are no cells, create a new one.
            if (cell == null)
            {
                cell = new UITableViewCell(UITableViewCellStyle.Default, CellId)
                {
                    BackgroundColor = UIColor.FromWhiteAlpha(0, 0f)
                };
                cell.TextLabel.TextColor = Owner.View.TintColor;
            }

            // Get the specific item to display.
            LayerDisplayVM item = ViewModelList[indexPath.Row];

            // Set the text on the cell.
            cell.TextLabel.Text = item.Name;

            // Return the cell.
            return cell;
        }

        /// <summary>
        /// This method allows the UITableView to know how many rows to render.
        /// </summary>
        public override nint RowsInSection(UITableView tableview, nint section)
        {
            return ViewModelList.Count;
        }

        /// <summary>
        /// Method called when a row is selected; notifies the primary view.
        /// </summary>
        public override void RowSelected(UITableView tableView, NSIndexPath indexPath)
        {
            // Deselect the row.
            tableView.DeselectRow(indexPath, true);

            // Select the layer.
            Owner.LayerSelectionChanged(indexPath.Row);
        }
    }
}

Your browser is no longer supported. Please upgrade your browser for the best experience. See our browser deprecation post for more details.