# Trend Lines - Switching Intervals

ICE Data Services -

When switching from a lower to higher interval on the chart, my Trend Line appears to be accurately drawn. The same does not appear to be true when starting from a higher interval and moving lower. Is this a bug?

All trend lines are drawn using two anchor points (Point A and Point B). These anchor points are calculated based on Time (X-Axis) and Price (Y-Axis) relative to the interval in question. For example, on the following 1 minute chart our Trend Line has the following anchor points:

 Point A Point B Price (Y-Axis) 75.58 75.33 Time (X-Axis) 13:40 14:46
For Point A, the High occurred at 13:40. For Point B, the High occurred at 14:46. Each value is based on the high of each bar covering a 1 minute period.

When we switch to a higher interval (10 minute), we see the Trend Line anchored to the appropriate bars.

The 14:46 bar is automatically lumped in with the 10 minute bar that begins at 14:40.

 10 Minute Chart Point A Point B Price (Y-Axis) 75.58 75.33 Time (X-Axis) 13:40 14:40

Trend Line Drawn on a Higher Interval

Now we will do the opposite by drawing the Trend Line on the 10 minute chart first then switching to a smaller interval.

Compared to the 1 minute interval the prices are the same. However, on the 10 minute interval, the Point B price is now based on the start of the 10 minute interval (14:40 as opposed to 14:46 on the 1 minute interval). Consequently, when moving to a 1minute interval, the anchor point is still locked in at 14:40, which is the start of the 10 minute interval bar.

On the 1 minute chart, the High is plotted at 14:46 but since the Trend Line was based on the start of the 10 minute interval, the anchor will appear at 14:40. The anchor points will appear to be offset in most cases unless the High of both intervals occurred around the same time (i.e. 14:40 on both the 1 and 10 minute charts).

Here is another quick example of a Trend line drawn at the lows of a Daily Chart. In this example, the Trend Line begins at the low on 1/29 and ends at the low on1/31:

When switching to a 60 minute interval, the anchor point will be set to the start of the larger interval (Daily) which is reflected as the first bar on the 60 minute chart. When a Trend Line is drawn on a larger interval, the start of that interval is used as the anchor point when moving to a smaller interval.

Please note this behavior is not a bug and applies to any change going from a higher to lower interval. This concept has been tested and confirmed in several 3rd party apps which are all subject to the same behavior.