The SpectraTrend HT has a viewing diameter of 1 inch which is an area of 0.79 sq in. The flash rate is 5 measurements per second or approximately 4 sq in. A typical update time is 15 seconds which would be approximately 60 sq in. A 30 second update time would be 120 sq in of measured area.
A line speed of 5 inches per second = 300 inches per minute =24 ft per minute is the speed at which the sensor measures without a gap (measured spots do not overlap). A line speed of less that 24 ft per minute would mean that the sensor is oversampling (measured spots overlap). For line speeds above 24 ft/min, there will be some gap area between the spots that is not measured. Regardless of the line speed, the measured area will be approximately the same (which is 4 sq in per second).