Trend curves:

• an overal picture of steady growth, although in some periods a fall - or strong increase - in demand may occur;
• drawing a smooth curve through the scatterd points;
• extending this curve into the future (forecasts);
• an assumption of the type of curve chosen.

Futurera have these trendcurves as options:

• Line
  Each time series is modeled using a straight line.
• Parabolic
  Each time series is modeled using a parabola, also called a quadratic curve.
• Exponential
  Each time series is modeled using an exponential curve, also called a geometric curve.
• Exponential
  Each time series is modeled using an exponential curve, also called a geometric curve.
• S-shaped (Gompertz)
  Each time series is modeled using a Gompertz curve. These curves take the shape of an S and come with lower and upper bounds on the curve.

Slope characteristics of trendcurves
The slope is the rate of growth of the various trend curves which gives straight lines when plotted against time. The slope characteristic for each trend curve is compared with the slope characteristic of the demand data and if the same linear relationship with time is obtained for a period of the data the the procedure would suggest that there is no apparent misfit to the demand data for the period.