MeasureRules.ApproximateValues Property

Gets or sets a value indicating whether or not it’s necessary to approximate values for measure rules.

Namespace: DevExpress.XtraMap

Assembly: DevExpress.XtraMap.v24.1.dll

NuGet Package: DevExpress.Win.Map

Declaration

C#

[DefaultValue(false)]
public bool ApproximateValues { get; set; }

VB.NET

<DefaultValue(False)>
Public Property ApproximateValues As Boolean

Property Value

Type	Default	Description
Boolean	false	true, to approximate values; otherwise, false.

Example

This example demonstrates how to generate bubble charts for a map control. Do the following:

• Create a VectorItemsLayer object and add it to the map control.
• Create a BubbleChartDataAdapter object and assign it to the VectorItemsLayer.Data property.
• Generate a data source with data for bubble charts and assign it to the DataSourceAdapterBase.DataSource property.
• Specify the mappings for bubble chart properties to corresponding columns in a datasource (a MapBubbleMappingInfo object that can be accessed using the BubbleChartDataAdapter.Mappings property).
• Specify the attribute mappings that are used to provide additional information about the map item to a map control.(an MapItemAttributeCollection object that can be accessed using the BubbleChartDataAdapter.Mappings property).

Form1.cs

    // Specify data for the bubble layer.
    BubbleLayer.Data = CreateData();
private IMapDataAdapter CreateData() {
    BubbleChartDataAdapter adapter = new BubbleChartDataAdapter() {
        DataSource = LoadData(),
        MeasureRules = CreateMeasureRules(),
        ItemMaxSize = 60,
        ItemMinSize = 10
    };

    #region #Mappings
    // Map the properties of chart items to the appropriate fields in the data source.
    adapter.Mappings.Latitude = "glat";
    adapter.Mappings.Longitude = "glon";
    adapter.Mappings.Value = "mag";
    #endregion #Mappings

    // Create attribute mappings to provide additional information about map items to the map.
    adapter.AttributeMappings.Add(new MapItemAttributeMapping("Magnitude", "mag"));
    adapter.AttributeMappings.Add(new MapItemAttributeMapping("Year", "yr"));
    adapter.AttributeMappings.Add(new MapItemAttributeMapping("Month", "mon"));
    adapter.AttributeMappings.Add(new MapItemAttributeMapping("Day", "day"));
    adapter.AttributeMappings.Add(new MapItemAttributeMapping("Depth", "dep"));

    return adapter;
}

private DataTable LoadData() {
    DataSet ds = new DataSet();
    ds.ReadXml(dataPath);
    DataTable dt = ds.Tables[0];
    dt.DefaultView.RowFilter = string.Format(CultureInfo.InvariantCulture, "(mag >= {0}) AND (mag <= {1})", minMagnitude, maxMagnitude);

    return ds.Tables[0];
}

private MeasureRules CreateMeasureRules() {
    MeasureRules measureRules = new MeasureRules();

    measureRules.ApproximateValues = true;
    measureRules.RangeDistribution = new LinearRangeDistribution();

    for (int i = minMagnitude; i < maxMagnitude; i++) {
        measureRules.RangeStops.Add(i);
    }

    return measureRules;
}

Form1.vb

    ' Specify data for the bubble layer.
    BubbleLayer.Data = CreateData()
Private Function CreateData() As IMapDataAdapter
    Dim adapter As New BubbleChartDataAdapter() With {.DataSource = LoadData(), .MeasureRules = CreateMeasureRules(), .ItemMaxSize = 60, .ItemMinSize = 10}

    '            #Region "#Mappings"
    ' Map the properties of chart items to the appropriate fields in the data source.
    adapter.Mappings.Latitude = "glat"
    adapter.Mappings.Longitude = "glon"
    adapter.Mappings.Value = "mag"