Wednesday, April 19, 2017

SearchResearch Challenge (4/19/17): Can you build (or find) an interactive widget for the island viewing problem?

I found myself trying to explain... 

... the "how high you have to be above the shore to see the Farallons" SRS Challenge to a friend.  

You remember the original Challenge about seeing the Farallons.  The question there was "can you see the Farallon Islands from the western shoreline of San Francisco?"  

There was an interesting observation in that post.  It turns out that you can see them from the bluff over the shore, but not when you're standing on the shore itself.  

We figured out that the explanation (ignoring atmospheric refraction effects) was that you have to be some distance above the sand in order to see the islands.  The question was really how high do you need to be to see the base of the islands?  

I told my friend about the math involved, waved my hands a lot, and drew a few diagrams on a piece of paper.  But sometimes, that's a bit, well... handwavy.  What I really wanted was a simple interactive graphic.  You know, the kind where you move the slider up and down, and it shows you how far out to sea you can see.  

An example of such a widget can be seen at the Physics Classroom Interactive Lens web page.  Here's an example: 

Side-by-side images from Physics Classroom, an interactive lens tool.
If you slide the focus slider (f) and the height slider (H), the image above changes in real-time
to show the relationships between focal length and the height of the original image.  

In this widget, when you slide the f and H sliders to the left or right, the paths of the lines change as you wiggle the variable values around.  

The Challenge this week is to figure out how to make such a thing to interactively show the relationship between height and visible distance.  

1.  Can you make an interactive widget that illustrates "how far out to sea can you see" without going into full-developer mode and writing a bunch of HTML, CSS, and Javascript?  

This Challenge is really for the teachers out there, who might like to make such a widget to help illustrate and teach a particular point.  But I suspect that having the ability to make these little instructive interactables would be a handy sensemaking tool in general.  

The REAL Challenge is to find a tool that will help you make such a thing. Once you find that tool, use it to make a simple interactive widget that illustrates this height-over-the-sand to visible-distance relationship.  

To get you started, here's a side-by-side sketch of what such a widget might look like.  In the first image, the observer's eye is 1.7 meters above the beach, which lets the observer see 4.7 km out to the visible horizon.  

The interaction is simple:  As you drag the red dot up, the value of the "height above the beach" changes.  In this image, it's 100m.  You can drag it down to 0, or up to a much higher number.   As you drag, the widget updates the "visible distance" number as you drag, and redraws the red line to touch a point on the circle (in this case, one that is 36 km out). 

In this next image, I've dragged it down a bit.  Here it's just 1.7 meters above the beach, and the red dotted line only goes out 4.7 km. As I drag the dot, the numbers should update, the line to the dot should move up and down, and the line to the point on the circumference of the circle should slide along to show the distance.  

NOTE:  These are sketches of what the widget might look like. They're NOT images from a working widget.  

The formula connecting these two variables look like this: 

     distance = 3.7 * (height ^ 0.5)  

where height is in meters, and distance is in kilometers.  (In the top example, since the height is 100m, the  square root of 100 is 10. Hence,  10 * 3.7 = 37 km.)  

To start off, see if you can find a toolkit that will let you make a simple widget--that is, one that lets you slide a slider.  (Don't worry about drawing the diagram on your first pass.)  Then, once you get that working, try to add in the diagram. 

Fair warning:  I don't know how hard this Challenge will be--I haven't solved it yet (or really started it).  On the other hand, this is much more like the SearchResearch Challenges analysts solve in their day-to-day work.  

I'll be fascinated to see what we can come up with.  

When you get something working, put it into a web page and post your URL to the comments section.  I'll collect them (along with your comments about how to answer the Challenge) next week. 

If it's going slowly, I'll give some hints over the next few days (and maybe extend the Challenge for a second week).  

As always, let us know what you're thinking about as you search.  What queries did you do?  What were your experiences in finding a tool to help build this thing?  How did you figure it all out? 

Search on!  


  1. relevant SERP - DRtW
    not what you are really looking for, but still a plausible response… an existing tool search. Used {can you see the farallon islands from san francisco}
    "We figured out that the explanation (ignoring atmospheric refraction effects) was that you have to be some distance above the sand in order to see the islands. The question was really how high do you need to be to see the base of the islands? "
    a found tool - approximation - 693 feet/~211 meters — dependent on a multitude of "real world" variables… and then eeeeekk
    seems even ~ 660 feet might suffice… 2x would more than do it
    " • For an observer standing on a hill or tower of 100 metres (330 ft) in height, the horizon is at a distance of 36 kilometres (22 mi)."

    Horizon Calculator
    using [horizon calculator]
    includes radar
    Farallon SERP
    question might be: can you see the mouse from Sutro/Twin Peaks… add ~ 4 miles?
    FI elevation info
    area island elevation list
    they are out there
    see Wednesday, December 10th, 2014 post
    home to 500 mice per acre
    food web
    seems vision is hard to come by…
    from a different island, Ripton Joseph Hylton
    should be more than possible from here - far/long - with the right conditions, optics, atmospherics, lighting, no Karl, etc. ~ 855 foot elevation

  2. Hello Dr. Russell, Remmij and everyone.

    Thanks for the links, Remmij. The tool you found is very helpful and the Minnie photo is super funny. Still need to check the other links.

    This SRS Challenge looks super complicated and at same time with lots of new tools and knowledge to discover. On other topic. I just read about this Fata Morgana and is super interesting and in a way related to our SRS Challenge, I think.

    1. nice connection to Fata, Ramón - you might find these interesting…
      had to go to the Weather Channel because Jeff Bezos isn't making enough money with the WaPo without making me pay to see the article you linked… :'\
      curiously, he is linked to 'illusion' in this article, 4/19/17: gospel of Jeff
      he might look good in the Captain's style of make-up too…?
      Eerie Look at Chicago, 4/18/17 - WX Channel
      ☀ ☀ ☀★ nice make-up and entertainingly credible information about fata morgana explained
      another short example by CaptainDisillusion
      the Captain's twitter - he is skeptical
      seeing isn't always believing… or becoming more disillusioned…

    2. Hi Remmij! I don't know why you can't read WaPo, I tried different ways and always was free to read.And found other great articles for example Introverts CEO You think is possible you can't read it because living on USA?

      About Fata Morgana, I will check your links. I found this article on Wired pretty good scholars believe Father Domenico Giardina recycled the account of another witness of fata morgana, as opposed to witnessing the phenomenon himself.

    3. I can see the WaPo article (which IS really interesting). It's possible that you've read > 9 articles this month on WaPo... that's their limit / month / reader. (Unless you have an account.)

    4. Thanks for the comment about the 9 articles on WaPo. I didn't know that and they don't mention the number of articles left to read. I have seen that on other sites like Harvard Business Review (they allow 4)

      About the calculators. Still trying to find the way to make them. Thanks for giving us another key to find the answer.

    5. Ramón/Dan,
      regarding the WaPo - idk, typically when a paper - the NYT for example - has a monthly view limit & it has been reached, there is a notice
      and a subscription pitch… but not seeing anything like that with the WaPo - can see their home page, but any article selected brings up
      the "milk screen/subscription pitch" (see screen grab)… doubt that I've seen 9 of their pieces this month, but possible.
      WaPo screen grab - going 'milky'
      Anyway, thought the "Flat-Earth: Finding the curvature of the Earth" link article was informative… thanks for pointing to it, Ramón.
      tried WolframAlpha too - think that might be a tool building option - if you paid…
      How Far Away Is…?
      Distance to the Horizon
      his tool:
      Calculating Altitudes of Distant Objects
      from France - related to the Chicago story
      maybe it would be best to catch the Farallones at sunset?
      more terms… Looming, Towering, Stooping, and Sinking

    6. Hello Remmij! Love your Sunset video. Thanks!

      About WaPo, I know it sounds dumb but have you tried pressing ESC when you arrive at that screen? It works many times.

      wolframalpha Widgets I am sure you, Remmij, can make this work. It is free but I don't have Java

      ["horizon calculator" widget] gives some possible apps to try.
      ["horizon calculator" online] [horizon calculator widgets]

      Calculate the distance to the horizon given the height above sea level in feet. Searched [Horizon]

      many widgets

    7. Ramón - the ␛key suggestion makes sense, but didn't work in this instance (WaPo) for me - will keep it in mind though - thanks for the tip. ⌆⌖⌀⎃
      know that the Farallones are 27 miles off SF… just plugged heights in until I was around that figure…
      Wolfram input view|eye height: 489.5 feet/0.080561339 mile(nautical) to horizon: 27.093 miles (Farallones to SF)/1,716,612.5 inches
      $66/yr seems high for casual use… but I'm sure Stephen has done the math.
      they may well be visible from the upper reaches of this…?
      like the night shots… wonder about lights on the Farallones?
      trespassing on a neighbor

  3. Still working on this Challenge.

    First searched how to create a widget without coding

    [create widget] and [create widget without coding] No good results for the challenge.

    Then tried to find the tool:

    [interactive visible distance horizon]

    Flat-Earth: Finding the curvature of the Earth

    [how far can you see to the horizon] In results, Remmij’s tool

    How to Calculate the Distance to the Horizon

    [distance to horizon calculator]

    Distance of the horizon calculator online

    Illustration similar to Dr. Russell’s

    Still not sure, these tools are the ones Dr. Russell is looking for.

    Now, I will try to find something that uses Google Maps to show how close you need to be to see something. I am not sure if I will find something or not.

    1. These are great distance-to-horizon calculators! Thanks for the find. They're half of what we're trying to make.

      Has anyone found a good way to make just these kinds of calculators?

    2. I found a way to create with Wolframalpha they have plenty already (needs JavaScript which my current laptop doesn't support) and then I am thinking there must be a way to create them with Google Forms or Google Spreadsheets. I'll check on that

  4. This comment has been removed by the author.

  5. I got lost here Gallery of
    Concept Visualizations
    and List
    of Physical Visualizations and Related Artifacts
    with so much to explore, but didn't find

    The Apparatus tool found here - Explorable Explanations
    -  might be useful. I will admit it is beyond me though.

  6. GeoGebra seems to have a few which look user generated. I don't have the maths chops to make them but it seems to have that functionality


    Found by searching "Distance to horizon slider" and clicking through via a blog debunking flat-earthism!

  7. oops forgot to add the link -

    grip point D and move to see the value of g change

    1. Thanks, Dolphin. That's fantastic.

      How did you find that site? What was your thought process to find that?


    2. Hi Russell,

      this is what i was meaning to share not sure how the wrong link appeared the link above you can grip point D and move to see the value of g change

      there was an earlier post from myself followed by the one above. At the outset this seemed a math-trigonometry problem, with that in mind I set out to look for a java based solution to solve the widget requirement.

      I know there are a few out there but didn't know it was possible to enter an equation. I searched a couple of sites and the one above seemed the most versatile.

      I still wasnt sure i could enter an equation, a bit of trial and error and then discovered the ability to enter equations ...

      thanks for your kind comments.

      keep up the good work!


    3. "1. Can you make an interactive widget that illustrates "how far out to sea can you see" without going into full-developer mode and writing a bunch of HTML, CSS, and Javascript? "
      … not sure what the inputs are based on — units, distance from the mainland, elevation, horizon relative to eye height…
      what is 'g' suppose to represent?
      dolphin worksheet/"first equation"
      slightly different URL…
      construction protocol - menu upper right
      math/physics in action…
      see: Pendulum Wave Machine (Simulation) fun to watch