Stand at a town-hall meeting with just a point cloud and try to explain some key point of evidence, try it again with an image, then try it again with both. Try colorizing a point cloud in a dark cave. How do you get true color on a LiDAR point cloud if not by using a RGB capable camera? As such, LiDAR is just as much a part of photogrammetry as the thumb is another finger. The “and” clause in the definition leaves it wide open. It does not restrict the medium to film, CMOS, CCD, rectangular imagery, push-broom, gray scale, RGB, NIR, Hyperspectral, active or passive systems, ground, hand-held, aerial, or satellite systems. They define it “as the art, science, and technology of obtaining reliable information about physical objects and the environment through processes of recording, measuring and interpreting photographic images and patterns of recorded radiant electromagnetic energy and other phenomena.” What’s the point of this? All too often we hear the debate about Photogrammetry vs LiDAR – thumbs vs fingers! Before we go much further let’s look at what ASPRS has used for decades as the definition of photogrammetry. Without a thumb and at least one finger I think they would have never been invented! It can be frustrating even when using both! Try opening a bag of chips with just your thumbs, or just your fingers. At last they are writing or drawing artfully and the world is at their disposal. Eventually, through lots of practice, they advance to the precision grip using the fingertips and thumb together to hold the utensil. For months they hold it like a club, using what is referred to as the power grip. We wait anxiously for them to just grip it. Watch a child learn to grasp a pencil or crayon. 🙂 Or point somebody out in a crowd using only your thumb. You might not meet a very welcome response. Or, try giving somebody the thumbs up sign but only using your middle finger. The thumb is definitely a strong point of the hand and we rely heavily upon it. If you are quite talented, you can do it.
Now, try doing a handstand without your thumbs.
It has only two phalanges rather than the three in the fingers. In fact, it directly opposes the fingers. Yet the thumb is distinctly different than the fingers. The backs of each have hair and a nail and are hairless on the palm-side. They each have hinged joints that flex toward the palm. The thumb and the fingers all share common features. Really, which is more important and useful, a thumb or a finger? Your thumb is undoubtedly more flexible and the largest of your “fingers.” You have four fingers and only one thumb on each hand. Thanks to Jeff Fagerman at Lidar USA for this article.
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