OE-6.1 Concepts of Remote Sensing

Work through these

• Remote sensing: definition, data and process

  What the phrase actually means: measuring something without touching it, and the chain from energy to answer. The whole subject is that chain, so keep the sequence in view.

• EM bands used in remote sensing

  Which parts of the spectrum are usable and why the others are not. Atmospheric absorption decides this, which the next item explains.

• Interaction with the atmosphere

  What the atmosphere does to energy on its way through, in both directions. The windows it leaves are exactly the bands the previous item listed, so the two belong together.

• Interaction with earth surface features: soil, water and vegetation

  How different surfaces reflect differently, which is the entire basis for telling them apart. Vegetation's sharp rise in the near infrared is the single most useful fact in this subject.

• Recording of energy by sensors

  How the energy becomes a number, which is where the instrument finally appears. It sets up the resolution vocabulary in the next topic.

• Transmission, reception and processing

  Getting the data down and into a usable state. Unglamorous, and it is where most of the cost and most of the delay actually sit.

• Image interpretation and analysis

  Turning an image into an answer, by eye and by algorithm. Both are still used, and knowing when visual interpretation beats classification is a real skill.

• Applications, advantages and limitations of remote sensing

  What the technique is good for and where it fails, stated together. The limitations item matters most, because remote sensing is frequently oversold.