A method for generating forest/non-forest maps from TanDEM-X interferometric data

In this paper a method for the generation of a global forest/non-forest map from TanDEM-X interferometric data is presented. The quality of interferometric products is strongly influenced by the specific characteristics of the illuminated land cover type. Over forested areas the presence of multiple scatterers at different heights and within a single resolution cell results in an increase of the interferometric phase uncertainty (the so-called volume decorrelation), whose intensity depends on several factors, such as the acquisition geometry, the sensor parameters, and the canopy density. From each TanDEM-X coherence map the volume decorrelation contribution can be estimated, leading to the derivation of a forest/non-forest map. This paper shows the developed approach for discriminating between forested and non-forested areas from TanDEM-X interferometric data, and presents some examples aimed at verifying the validity of the proposed method. From this, mosaics can be generated from the TanDEM-X quicklook data set at a final resolution up to 25 m × 25 m.