Maria globe client/Auto follow

In this section, we will utilise the globe control auto follow functionality.

2D

• valid for tracks and all draw object types
• the specified object will always be displayed with its center point in the center of the screen.
• if the item position is changed, the map area will be adjusted accordingly.

3D

• valid for tracks and point objects only

Auto follow control and display

Add the following GUI elements to your main window:

• Check box to enable/disable auto follow
• Text box for display of currently followed item

The XAML could look something like this:

...
<GroupBox Header="Auto follow">
    <StackPanel>
        <CheckBox Margin="3"
                  Content="Follow selected"
                  IsChecked="{Binding IsAutoFollowActive}" />
        <Label Content="Currently followed:" FontWeight="DemiBold" />
        <TextBox Margin="3"
                 Text="{Binding AutoFollowItemName, Mode=OneWay}" 
                 IsReadOnly="True"/>
    </StackPanel>
</GroupBox>
...

In MainViewModel implement:

• Auto follow property,
• auto update property with timer, initialised in during the LayerInitialized event handler.

...
public bool IsAutoFollowActive
{
    get
    {
        return GlobeMapViewModel.AutoFollow.TargetItem != null;
    }

    set
    {
        if (!(value && GlobeMapViewModel.AutoFollow.FollowSelectedItem()))
            GlobeMapViewModel.AutoFollow.TargetItem = null;

        NotifyPropertyChanged(() => IsAutoFollowActive);
        NotifyPropertyChanged(() => AutoFollowItemName);
    }
}

public string AutoFollowItemName
{
    get
    {
        if (GlobeMapViewModel?.AutoFollow?.TargetItem != null)
        {
            return GlobeMapViewModel.AutoFollow.TargetItem.ToString();
        }

        return "Inactive";
    }
}
...

Running with auto follow

Activating/deactivating auto follow functionality, observe the following:

• in 3D mode, tracks and point objects only can be selected.
• the map will re-position to the activated item if the map is panned.
• the map will re-position to the activated item if the item is moved.
• the activated item will stay activated also when deselected in the map and when another item is selected.
  • To activate another item - deactivate, then activate the new item.

No auto follow, 2D
Auto follow volume object, 2D	Auto follow line object, 2D
Auto follow point object, 2D	Auto follow track, 2D
Auto follow point object, 3D	Auto follow track, 3D