Set initial map area

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Sample viewer app

Display a map with a predefined initial extent.

screenshot

Use case

You can set a map's initial location when you want to highlight a particular feature or area to establish the context.

How to use the sample

When the map loads, note the specific location of the initial map view.

How it works

  1. Create a Envelope(xMin, yMin, xMax, yMax, SpatialReference).
  2. Create a Viewpoint passing in the envelope.
  3. Call setInitialViewpoint(viewpoint) on the Map to set the initial map area.

Relevant API

  • Basemap
  • Map
  • MapView

About the data

The map opens with satellite imagery of a guitar-shaped field in the Pampas region of north central Argentina.

Tags

basemap, center, envelope, extent, initial, lat, latitude, level of detail, location, LOD, long, longitude, scale, zoom level

Sample Code

SetInitialMapArea.cppSetInitialMapArea.cppSetInitialMapArea.hSetInitialMapArea.qml
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// [WriteFile Name=SetInitialMapArea, 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 "SetInitialMapArea.h"

#include "Map.h"
#include "MapQuickView.h"
#include "Basemap.h"
#include "Viewpoint.h"
#include "Envelope.h"

using namespace Esri::ArcGISRuntime;

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

SetInitialMapArea::~SetInitialMapArea() = default;

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

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

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

  // create a new basemap instance
  Basemap* basemap = new Basemap(BasemapStyle::ArcGISImageryStandard, this);
  // create a new map instance
  m_map = new Map(basemap, this);
  // set the initial viewpoint
  Envelope envelope(-12211308.778729, 4645116.003309, -12208257.879667, 4650542.535773, SpatialReference(102100));
  m_map->setInitialViewpoint(Viewpoint(envelope));
  // set map on the map view
  m_mapView->setMap(m_map);
}

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