  This communication describes a preliminary research on detection of big
masses of plastic (marine litter) on the oceans and seas using EO (Earth
Observation) satellite systems. Free images from the Sentinel 2 (Copernicus
Project) platform are used. To develop a plastic recognizer, we start with an
image where we can find a big accumulation of "nonfloating" plastic: Almer\'ia
greenhouses. We made a test using remote sensing differential indexes, but we
got much better results using all available wavelengths (thirteen frequency
bands) and applying Neural Networks to that feature vector.
