Web tiled layer

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Sample viewer app

Display a tiled web layer.

screenshot

Use case

Tiled map services are a set of pre-generated images (e.g. "tiles") arranged in folders for each row, column, and zoom level. As you navigate the map, map tiles are requested for the current extent. ArcGISTiledLayer and WmtsLayer are types of tiled map services used for specific data types. WebTiledLayer is useful for displaying other data sources that contain tiles arranged in a row/column/level directory structure, such as OpenStreetMap.

How to use the sample

Run the sample and a map will appear. As you navigate the map, map tiles will be fetched automatically and displayed on the map.

How it works

Web tiled services use a uniform addressing scheme with pre-rendered tiles. Image tiles are accessed via a URL template string, with parameters for subdomain, level, column, and row.

  • Subdomain is optional and allows Runtime to balance requests among multiple servers for enhanced performance.
  • Level, row, and column select the tiles to load based on the visible extent of the map.
  1. Create a WebTiledLayer from a URL and a list of subdomains.
  2. Create a new Basemap from the layer.
  3. Update the attribution on the layer. Note: this is a necessary step because web tiled services don't have associated service metadata.
  4. Display the basemap.

For more information about web tiled layers, see the following resources:

Relevant API

  • Basemap
  • WebTiledLayer

About the data

The basemap in this sample is provided by Stamen Design. Stamen publishes tiled services based on OpenStreetMap data with several unique styles applied.

Tags

layer, OGC, Open Street Map, OpenStreetMap, stamen.com, tiled, tiles

Sample Code

Web_Tiled_Layer.cppWeb_Tiled_Layer.cppWeb_Tiled_Layer.hWeb_Tiled_Layer.qml
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// [WriteFile Name=Web_Tiled_Layer, Category=Layers]
// [Legal]
// 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.
// [Legal]

#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD

#include "Web_Tiled_Layer.h"

#include "Map.h"
#include "MapQuickView.h"
#include "Basemap.h"
#include "WebTiledLayer.h"
#include "Viewpoint.h"
#include "Point.h"

#include <QStringList>

using namespace Esri::ArcGISRuntime;

Web_Tiled_Layer::Web_Tiled_Layer(QQuickItem* parent /* = nullptr */):
  QQuickItem(parent)
{
}

Web_Tiled_Layer::~Web_Tiled_Layer() = default;

void Web_Tiled_Layer::init()
{
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<Web_Tiled_Layer>("Esri.Samples", 1, 0, "Web_Tiled_LayerSample");
}

void Web_Tiled_Layer::componentComplete()
{
  QQuickItem::componentComplete();

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");

  // Set up the tiled layer parameters
  const QString templateUrl = "https://stamen-tiles-{subDomain}.a.ssl.fastly.net/terrain/{level}/{col}/{row}.png";
  const QStringList subDomains { "a", "b", "c", "d" };
  const QString attributionText = "Map tiles by <a href=\"https://stamen.com\">Stamen Design</a>, "
                                  "under <a href=\"https://creativecommons.org/licenses/by/3.0\">CC BY 3.0</a>. "
                                  "Data by <a href=\"https://openstreetmap.org\">OpenStreetMap</a>, "
                                  "under <a href=\"https://www.openstreetmap.org/copyright\">ODbL</a>.";

  // Create the WebTiledLayer with a template URL, sub domains, and copyright information
  WebTiledLayer* webTiledLayer = new WebTiledLayer(templateUrl, subDomains, this);
  webTiledLayer->setAttribution(attributionText);

  // Create a basemap from the WebTiledLayer
  Basemap* basemap = new Basemap(webTiledLayer, this);

  // Create a map using the WebTiledLayer basemap
  m_map = new Map(basemap, this);

  // Set an initial viewpoint
  Point pt(-13167861.0, 4382202.0, SpatialReference::webMercator());
  Viewpoint vp(pt, 50000.0);
  m_map->setInitialViewpoint(vp);

  // Set map to map view
  m_mapView->setMap(m_map);
}

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