Our Problem Vs Our Image!!!
All remote sensing projects begin with a problem we are trying to solve: We may want to find out where the oil is,where to drill, the best way to get to a drill site, and where to build a pipeline or a gas plant for the least cost and with minimal environmental disruption. We may wish to lay out a seismic program most efficiently or find out where a competitor has shot a seismic program. We require a source of water for drilling, for a coal slurry pipeline, or for keeping dust down in a mining operation. If we are involved with mineral exploration, we will be looking for any evidence of mineralization in a new mineral province, or which direction to extend a known deposit. We need to know the state of the terrain before mining so that we know how to restore it to its pre-mining condition. Was there natural acid drainage before mining or is it coming from the tailings ponds?
In order to determine the best imagery to evaluate, we must know what we are looking for. Is the area large or small? Does our problem require us to see fine details (centimeters up to 10 m resolution), moderate detail (20–100 m resolution), or regional features (100 m to 1 km resolution or more)? What scale do we wish to work with? Do we need to detect color changes (e.g., lithology, alteration) or vegetation stress? Is the area always under clouds? Is the area in a polar region that has an extended dark season? Are we looking for changes in moisture conditions? Is the area under water? Do we require or want a certain date or specific time of year? Do we need multitemporal (repetitive) coverage or historical coverage? Finally, how much time do we have and what kind of budget do we have to work with? Should we go to a vendor, the government, or process the data ourselves? The answers to these questions will determine the products that are acquired and the types of analyses that are possible.