Comparison of vegetation measured from three different distances

Remote sensing is widely used for the monitoring of forests and the VIS/NIR reflectance is commonly used for the identification and characterization of the vegetation. The reflectance data obtained at higher altitudes is some kind of average over a certain extension of area, and also the atmosphere that lies between the sensor and the object affects the data. Therefore, in the interpretation of the remote sensing data, knowing the difference between the data obtained at different scales and distances is important. The authors measured the spectra of trees at three different scales: 1) individual leaves, 2) part of a tree seen from a distance of 40 m, 3) mixture of several different trees seen from a helicopter, and investigated what affects the data during the scaling up of the measurements