Min-Max scale

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Restrict zooming between specific scale ranges.

screenshot

Use case

Data may only appear at a certain scale on a map, and may be visually lost if zooming too far in or out. Setting the minimum and maximum scales ensures the zoom extents are appropriately limited for the purposes of the map.

How to use the sample

Zoom in and out of the map. The zoom extents of the map are limited between the given minimum and maximum scales.

How it works

  1. Create a Map object.
  2. Set min and max scales of map with setMaxScale() and setMinScale().
  3. Set the map to a MapView object.

Relevant API

  • Map
  • Basemap
  • MapView
  • ViewPoint

Tags

area of interest, level of detail, maximum, minimum, scale, viewpoint

Sample Code

MinMaxScale.cppMinMaxScale.cppMinMaxScale.hMinMaxScale.qml
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// [WriteFile Name=MinMaxScale, Category=Maps]
// [Legal]
// Copyright 2018 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 "MinMaxScale.h"

#include "Map.h"
#include "MapQuickView.h"

using namespace Esri::ArcGISRuntime;

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

void MinMaxScale::init()
{
  // Register the map view for QML
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<MinMaxScale>("Esri.Samples", 1, 0, "MinMaxScaleSample");
}

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

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

  // Create a map using the streets basemap
  m_map = new Map(BasemapStyle::ArcGISStreets, this);

  // Establish the minimum and maximum scales for the map
  m_map->setMaxScale(2000);
  m_map->setMinScale(8000);

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

  Point edinburgh(-3.1927,55.9515, SpatialReference(4326));
  m_mapView->setViewpointCenter(edinburgh);
}

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