A two-axis adjusted vegetation index (TWVI)

Based on the soil line concept, various kinds of vegetation indices have been proposed to minimize soil background influences in the inventory of forest resources and the prediction of vegetation biomass. Unfortunately, those indices can only reduce soil moisture effect on remote sensing data parallel to the axis, the direction of the so-called soil line, failing when different soil types appear (in the direction perpendicular to the soil line). A two-axis adjusted vegetation index is presented here to diminish most soil background influences. It is shown to be more suitable as a global monitoring vegetation index than other indices.