TdxMapImageTileLayer Class

A map tile layer.

Declaration

TdxMapImageTileLayer = class(
    TdxMapLayer
)

Remarks

A map tile layer loads data from a supported map provider server.

Available Map Tile Providers

You can assign references to the following classes to the ProviderClass property to select the corresponding tile provider:

TdxMapControlAzureMapImageryDataProvider

Loads map tiles from Azure Maps servers.

TdxMapControlOpenStreetMapImageryDataProvider

Loads map tiles from the OpenStreetMap service.

Tile Provider Selection at Design Time

You can use the Object Inspector to select any available tile data provider at design time. Select an image tile layer, click the Provider node’s drop-down button and select the required data provider in the menu.

Main API Members

The list below outlines key members of the TdxMapImageTileLayer class. These members allow you to configure map tile provider settings and configure core map layer functionality.

Tile Data Provider-Related API Members

IsReady

Allows you to identify if the latest data request is completed.

Provider

Provides access to tile data provider settings.

ProviderClass | ProviderClassName

Allow you to switch between supported tile data providers.

Coordinate Conversion Methods

GeoPointToMapUnit | GeoPointToScreenPoint

Convert geographical coordinates into map and screen coordinates.

MapUnitToScreenPoint

Converts a point position in map measurement units into screen (pixel) coordinates.

ScreenPointToGeoPoint | ScreenPointToMapUnit

Convert screen (pixel) coordinates into geographical and map point coordinates.

General-Purpose API Members

AlphaBlendValue

Allows you to adjust the tile layer opacity.

Collection

Provides access to the parent map layer collection.

Index

Specifies the map layer’s index in the parent collection.

IsActuallyVisible

Identifies if the parent Map Control displays the map layer.

Visible

Specifies if the map layer is visible.

Code Example: Add a Tile Map Layer and Load Azure Maps Data

The following code example implements a procedure that accepts an Azure Maps account key, creates and configures a map tile layer, and loads data:

Delphi

uses
  dxAzureMapImageryDataProvider;  // This unit declares TdxMapControlAzureMapImageryDataProvider
// ...

procedure TMyForm.AddAzureMapLayer(const AAzureKey: string);
var
  ATileLayer: TdxMapImageTileLayer;
  AProvider: TdxMapControlAzureMapImageryDataProvider;
begin
  ATileLayer := dxMapControl1.Layers.Add(TdxMapImageTileLayer) as TdxMapImageTileLayer;
  ATileLayer.ProviderClass := TdxMapControlAzureMapImageryDataProvider;
  AProvider := ATileLayer.Provider as TdxMapControlAzureMapImageryDataProvider;
  AProvider.BeginUpdate;  // Initiates the following batch change
  try
    AProvider.AzureKey := AAzureKey;  // Assigns the Azure account key
    AProvider.Tileset := TdxAzureMapTileset.Satellite;  // Changes the default tileset
    AProvider.MaxParallelConnectionCount := 8;  // Explicitly defines the number of parallel connections
  finally
    AProvider.EndUpdate;  // Calls EndUpdate regardless of the batch operation's success
  end;
end;

C++

#include "dxAzureMapImageryDataProvider.hpp"  // This header declares TdxMapControlAzureMapImageryDataProvider
// ...

void __fastcall TMyForm::AddAzureMapLayer(const UnicodeString &AAzureKey)
{
  TdxMapLayer *ALayer;
  TdxMapImageTileLayer *ATileLayer;
  TdxMapControlAzureMapImageryDataProvider *AProvider;

  ALayer = dxMapControl1->Layers->Add(__classid(TdxMapImageTileLayer));
  ATileLayer = dynamic_cast<TdxMapImageTileLayer*>(ALayer);
  ATileLayer->ProviderClass = __classid(TdxMapControlAzureMapImageryDataProvider);
  AProvider = dynamic_cast<TdxMapControlAzureMapImageryDataProvider*>(ATileLayer->Provider);
  AProvider->BeginUpdate();  // Initiates the following batch change
  try
  {
    AProvider->AzureKey = AAzureKey;  // Assigns the Azure account key
    AProvider->Tileset = TdxAzureMapTileset::Satellite;  // Changes the default tileset
    AProvider->MaxParallelConnectionCount = 8;  // Explicitly defines the number of parallel connections
  }
  __finally
  {
    AProvider->EndUpdate();  // Calls EndUpdate regardless of the batch operation's success
  }
}

Direct TdxMapImageTileLayer Class References

The following public API members reference a TdxMapImageTileLayer object:

TdxCustomMapControl.AddImageTileLayer

Creates a new image tile layer and adds it to the map layer collection.

TdxMapLayers.Items

Provides indexed access to stored map layers.

Related Compiled Demo

To see map tile layers with all supported information providers in action, run the Mapping demo in the VCL Demo Center installed with compiled DevExpress demos. Click the Data Providers item in the side bar to the left and switch between available data providers in the Ribbon UI.

Download: Compiled VCL Demos

Tip

You can find full source code for installed complied Map Control demos in the following folder:

%PUBLIC%\Public Documents\DevExpress VCL Demos\MegaDemos\Product Demos\ExpressMapControl

Inheritance

TObject

TPersistent

TComponent

TcxCustomComponent

TcxComponentCollectionItem

TdxMapLayer

TdxMapImageTileLayer