### Off-Scale Channel Indicator (XTD Indicator)

The indicator is designed to monitor the ship's position relative to the route axis and the cross-track distance (XTD) limits on the current route leg.

```{hint}
The indicator is only available when a route is activated.
```

The **XTD** boundaries displayed on the indicator may be symmetric or asymmetric, depending on the route settings.

![XTD indicator](images/Chanel_1.png)

| № | Element | Description |
|---|---------|----------|
| 1 | **Current route leg axis** | Route centerline |
| 2 | **Left XTD boundary** | Left minimum allowable deviation boundary |
| 3 | **Right XTD boundary** | Right minimum allowable deviation boundary |
| 4 | **Distance to axis** | Distance from the own ship to the route axis |
| 5 | **Scale** | In current units of measurement |
| 6 | **Ship** | Off-scale ship symbol. Symbol rotation indicates the ship's direction of movement relative to the current route leg axis |
| 6 | **Red band** | Band occupied by the ship in the track lane. Red — the ship has partially or fully exceeded the XTD limits |
| 7 | **Green band** | Band occupied by the ship in the track lane. Green — the ship is fully within the XTD limits |

```{important}
Calculation of the band occupied by the ship is only performed when heading data is available. In the absence of a heading sensor, the off-scale ship symbol is always displayed vertically.
```

With a significant deviation from the route, to facilitate return to the route, the indicator will always display the route axis, XTD band, and ship symbol.

![XTD exceeded indicator](images/Chanel_2.png)

| № | Element | Description |
|---|---------|----------|
| 1 | **Route** | Track lane |
| 2 | **Ship** | Off-scale ship symbol. Symbol rotation indicates the ship's direction of movement relative to the current route leg axis |

```{caution}
The indicator calculates the ship's position on the current route leg. If a different WP is selected in the {doc}`Routes </sections/routes/track-plotting/index>` window, the indication of the ship's position on the route leg may not correspond to reality.

This situation may occur with a significant deviation from the route and subsequent return to it.

Exercise particular caution when interpreting the **Channel** indicator readings.
```