Set map spatial reference

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Sample viewer app

Specify a map's spatial reference.

screenshot

Use case

Choosing the correct spatial reference is important for ensuring accurate projection of data points to a map.

How to use the sample

Pan and zoom around the map. Observe how the map is displayed using the World Bonne spatial reference.

How it works

  1. Create a Map object using a spatial reference e.g. Map(SpatialReference.create(54024)).
  2. Create a Basemap object using an ArcGISMapImageLayer object.
  3. Set the base map to the map.
  4. Set the map to a MapView object.

The ArcGIS map image layer will now use the spatial reference set to the ArcGIS map (World Bonne (WKID: 54024)) and not it's default spatial reference.

Relevant API

  • ArcGISMapImageLayer
  • Basemap
  • Map
  • MapView
  • SpatialReference

Additional information

Operational layers will automatically project to this spatial reference when possible.

Tags

project, WKID

Sample Code

SetMapSpatialReference.cppSetMapSpatialReference.cppSetMapSpatialReference.hSetMapSpatialReference.qml
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// [WriteFile Name=SetMapSpatialReference, Category=Maps]
// [Legal]
// 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.
// [Legal]

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

#include "SetMapSpatialReference.h"

#include "Map.h"
#include "MapQuickView.h"
#include "Basemap.h"
#include "SpatialReference.h"
#include "ArcGISMapImageLayer.h"
#include <QUrl>

using namespace Esri::ArcGISRuntime;

SetMapSpatialReference::SetMapSpatialReference(QQuickItem* parent) :
  QQuickItem(parent)
{
}

SetMapSpatialReference::~SetMapSpatialReference() = default;

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

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

  // find QML MapView component
  m_mapView = findChild<MapQuickView*>("mapView");
  m_mapView->setWrapAroundMode(WrapAroundMode::Disabled);

  // Create a new map with the spatial reference
  m_map = new Map(SpatialReference(54024), this);

  // create the URL pointing to the map image layer
  QUrl imageLayerUrl("https://sampleserver6.arcgisonline.com/arcgis/rest/services/SampleWorldCities/MapServer");

  // construct the ArcGISMapImageLayer using the URL
  m_imageLayer = new ArcGISMapImageLayer(imageLayerUrl, this);

  // create a Basemap and pass in the ArcGISMapImageLayer
  m_basemap = new Basemap(m_imageLayer, this);

  // set the ArcGISMapImageLayer as basemap
  m_map->setBasemap(m_basemap);
  // set map on the map view
  m_mapView->setMap(m_map);
}

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