Technical indicators are a fundamental part of technical analysis and are typically plotted as a chart pattern to try to predict the market trend. Indicators generally overlay on price chart data to indicate where the price is going, or whether the price would go bullish or bearish.
Trend lines drawn on the GBPUSD chart above indicates the general course or tendency of the market, Tuesday after the New York session closes at 5:00 pm EST (EDT), the price 1.2385 would have been met.