The possible value of historical imagery
Historical imagery is stored in numerous databases all over the world. This way, historical data can be compared with more recent observations. If you look at historical facts and the situation as it was in previous days, it will give you an insight in how rapid or slow particular phases went. Nowadays, the imagery in some project is measured against historical imagery. Historical changes that were already recorded have become more valuable, because it gives analysts a sounder basis for deducting conclusions. Historical changes are also a reliable source of evidence, because they are always based on facts instead of presumptions.