Comparison of multispectral video and SPOT-1 HRV observations for cotton affected by soil salinity

Abstract

A 15-ha field of cotton (Gossypium hirsuiutn L,) with an erratic pattern of soil salinity was overflown twice during the 1989 growing season with each of two sensor systems, a multispectral videography system and the High Resolution Visible (HRV) scanner of the French polar-orbiting satellite SPOT. The objectives were to compare the responses of the two sensor systems and to relate vegetation indices calculated from them to plant cover and lint yield (kgha⁻¹) observations for 36 sites located at the intersections of a square 60 m grid laid off in the field. The range in responses, expressed as digital counts, was much greater for the video than for the HRV. For paired dates of acquisitions, the agreement between near-infrared and red bands between systems was almost as good as within systems. Yield and plant cover could also be estimated about equally well from vegetation indices calculated from both systems. Consequently, it is concluded that the video observations provided essentially the same information as SPOT-1 HRV observations and could be used in lieu of, or to supplement, SPOT observations. Videography could also be used to obtain high resolution samples within Landsat Multispectral Scanner (MSS) and NOAA AVHRR scenes or to augment those coverages.