Opposable Thumbs versus Fingers

Thanks to Jeff Fagerman at Lidar USA for this article.

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. The thumb and the fingers all share common features. They each have hinged joints that flex toward the palm. The backs of each have hair and a nail and are hairless on the palm-side. Yet the thumb is distinctly different than the fingers. In fact, it directly opposes the fingers. It has only two phalanges rather than the three in the fingers. The thumb also has much more dexterity.

Now, try doing a handstand without your thumbs. If you are quite talented, you can do it. For most of us, it is quite a surprise. The thumb is definitely a strong point of the hand and we rely heavily upon it. Or, try giving somebody the thumbs up sign but only using your middle finger. You might not meet a very welcome response. 🙂 Or point somebody out in a crowd using only your thumb.

Watch a child learn to grasp a pencil or crayon. We wait anxiously for them to just grip it. For months they hold it like a club, using what is referred to as the power grip. Eventually, through lots of practice, they advance to the precision grip using the fingertips and thumb together to hold the utensil. At last they are writing or drawing artfully and the world is at their disposal.

Try opening a bag of chips with just your thumbs, or just your fingers. It can be frustrating even when using both!

Zippers. Without a thumb and at least one finger I think they would have never been invented!

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.

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.”

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. The “and” clause in the definition leaves it wide open. As such, LiDAR is just as much a part of photogrammetry as the thumb is another finger.

How do you get true color on a LiDAR point cloud if not by using a RGB capable camera?
Try colorizing a point cloud in a dark cave. There’s something missing – light.

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. The imagery is much easier to understand and makes it possible for the audience to see what the LiDAR point cloud exposes.

Try digitizing the myriad of lines on a utility pole, the anchor points, the destinations, from just imagery or just a point cloud. The combination is far, far better than either alone.
Show a dozer operator a design built upon a bare earth surface model, then show them the imagery clearly showing the heavy forest between them and their finished work. They will appreciate the heads up for their estimate.

I could go on and list the pros and cons of each as others have over and over. The fact is, they both work well for what they are intended and work best together. Sometimes you only need one (thumbs up!), sometimes you need them all (holding a hammer).

Oh, and we have two arms, each with a hand. Somebody thought one wasn’t enough and three would have been too many.

Soon we will take issue with the readiness of UAVS with LiDAR. You might argue that their time has not yet come – but it is here today like it or not.

Please drop by our website at www.lidarusa.com to see what’s new with UAV’s and LIDAR.

PS: This story was inspired by a recent injury to my thumb. We really, really use the thumb for a lot more than we think.

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