SearchResearch Challenge (6/28/17): How can you see across time?
28 June 2017 | 8:43 pm

Seeing a place once... 

... and then seeing it again 10 years later is often a shock, but also sometimes a revelation.  Things change, places are transformed, the new washes in--and if you look over a long enough period, you can see the planet change.  

As an example, here's a place that's not far from my old work location from 2007: 

Of course, this is California, so things change quickly.  This is the same place 8 years later.  

And this happens at larger scales as well.  Here's San Francisco in 1938: 

And SF a 21 years later: 

In the course of doing my research on various SRS Challenges, I've done a lot of looking for images at time X and then the same shot a few years later.  But even after I've found them, the problem of comparing them is always problematic.  I can sometimes put them up side-by-side, like this: 

While that's handy, it's really hard to compare individual locations.  I end up using two fingers to locate the same spots on both images, then flicking my eyes back and forth.  

This leads me to ask you for help.  Our Challenges this week are:  

1.  Is there any way I can make a web page that lets me have two pictures side-by-side and then have a slider that let's me easily move a divider between one image and the other?  (Here's a mockup of what I'd like. In this illustration, you can click on the circle and drag the divider back and forth to see more of one image or the other.) 

2. In this same vein, I'd like to see a nice time lapse of a place--ANY place.  (You can probably find an aerial time lapse of any particular large city.)  Can you find a worldwide tool that will let me see any place on the planet with a roughly 10 year timelapse view? I'm looking for something that will allow me to see this: 

More particularly, can I get a time-lapse of other places?  (Say, Antarctica, Tahiti, or the Canary Islands.)  

So, class... we're looking for tools this week.  Can you locate these?   (And are there other tools that can help us look at time-based images for comparison?)  

And, if you manage to find a timelapse tool, what's the most interesting place you've found?  

As always, let us know HOW you found the answer (and, for this week), what's the most interesting!

Search on!


Addendum:  Regular Reader Judith dropped me a note to say that there's a bit more to the "floaters" story that I should have mentioned in our last Challenge.  She wrote to me with a great comment: 

"Floaters that appear gradually and are there all the time are nothing to worry about.  However, if there is a sudden increase of floaters, it may be a medical emergency as this can be the sign of a retinal detachment.

Anyone who experiences an onrush of floaters should see an ophthalmologist immediately."  

Thanks, Judith.  (I'm going to edit my original post to reflect this.) 

Answer: Seeing things?
27 June 2017 | 11:01 pm

We see things all the time...  

.. you often just don't notice.  This is part of the complexity of this Challenge--you see these visual effects often, but we almost never talk about them.  If that's true, HOW do you search for them?  

Here's what I did to find these answers.  

1.  When I went for a run a while ago, I scampered around a blind corner and smashed my forehead into a stop sign.  The impact didn't hurt much, but it dropped me flat on my back onto the sidewalk.  I got up quickly and resumed running.  Nothing was hurt, BUT this is what my visual field looked like: 

There was a relatively large C-shaped fuzzy spot just to the left of my visual center.  I fell on my back, so my eyes were untouched by the accident.  The good news is that this fuzziness went away on its own after about 1 hour.  Challenge:  WHAT is this visual disruption called?  Should I worry about it? 

As Remmij pointed out, this IS in Cupertino (when I worked for Apple), but not actually at this corner.  (I used this photo because it was really close to where the "stoppage" actually happened. But the real place is pretty unphotogenic.)  

I searched for: 

     [ C-shaped blur vision ] 

and found the Wikipedia article about scintillating scotomas, which are shimmering regions of the visual field that are often C-shaped and associated with migraines.  Here are two images from the Wikipedia article that illustrate this.  

These both are C-shaped in the same way as my blurred vision, and my visual effect did scintillate a bit, but this clearly wasn't a migraine.  Could a fairly simple head trauma cause this?  

As I read the article, I found a link to scotoma without the "scintillating" and found that this effect is sometimes caused by preeclampsia (a disorder sometimes found during pregnancy, not my problem), poisoning, demyelinating diseases, or migraines.  

Since this was a one time event, I wondered if my scotoma could be caused by hitting my head.  It's quite possible that I hit the back of my head on the sidewalk when I was abused by the stop sign. 

My next query was for: 

     [ scotoma head trauma ] 

I used the medical terminology "trauma" rather than "hitting my head" in order to get more medical results in my SERP.  

The second result led me to the page "Visual fields in brain injury" I learned something even more specific: that scotomas that look exactly like mine are also called Unilateral Temporal Crescent Scotoma or Half Moon Syndrome.  The page indicated that this can be caused by head trauma, so I modified my search to include this new descriptive term: 

     [ unilateral temporal crescent scotoma head trauma ] 

and found a few more pages (such as this one) that describe the visual effects after "traumatic brain injury" (TBI).  Clearly, I just had a whack on the head, and not really a serious brain injury.  But this IS one of the ways that your visual system can be disrupted.  

Bottom line: I had a scotoma after whacking my head pretty hard on the concrete.  Luckily, it resolved itself pretty quickly, so I never developed any of the more outrageous forms of the effect.  

2.  Unrelated to Challenge #1, I noticed recently that whenever I look up into a clear blue sky (or at a blank white wall) I see lots of small circles and a few "threads" kind of wandering around.  They're not big enough to obscure anything, and I don't notice them during the ordinary course of the date... but they're kind of odd.  Again, WHAT are these things called?  Should I worry about them?  
For this one, I did the query: 

     [ circles threads in vision ] 

which gave me a BUNCH of results about "floaters."  I mean, everything was about "floaters."  What are they?  Clicking on a few links (here's a good one from Eye Health Web) taught me that they are also known as vitreous floaters or eye spots, are tiny specks, circles, or thread-like clouds that appear in your field of vision. They are a common occurrence, and they can appear periodically or they can be around for quite a while.  

Eye floaters usually vary in size and shape. Although they can appear in youth, most people who experience eye floaters are over the age of 50 (that would be me).   Eye floaters can usually be seen when looking at plain, light-colored backgrounds (such as a wall or the sky) and may appear black, gray, white, or “see through.”

So, nothing to worry about, they're just a side-effect of having aging eyes.  Nothing to worry about.  

3.  Unrelated to #1 or #2:  Even though I have lots of experience seeing the world, I also noticed that when I close my eyes for a second and then look downward rapidly without opening my eyes, I see a fairly large circle appear and then disappear in a couple of seconds.  I'm surprised I've never noticed this before, but I have no idea what this visual effect is called or what causes it!  Can you tell me?  (And let us know if you see this circle appearing when you look down with closed eyes.)  

For this visual effect, my search was: 

     [ ring of light when I close my eyes ] 

which led me to a slightly gossipy site (Huffington Post) with a somewhat glib article about "rings of light"... but also had another word:  phosphene.  Since I didn't know that word, I did a: 

     [ define phosphene ] 

which told me that it was a "a ring or spot of light produced by pressure on the eyeball or direct stimulation of the visual system other than by light."  

Interesting.  So I changed my search to: 

    [ ring phosphene when I close my eyes ] 

which led me to Optometry Forum, which has an article on exactly this phenomenon.  That article suggested I do a search for: 

     [ phosphene entoptic phenomena ] 

which in turn led me to the Wikipedia page on Entoptic Phenomena (there IS such a page?).  There I learned more about floaters (confirming what I learned above), and more mentions of phosphenes as the probable cause of the rings I see when closing my eyes and looking down. 

--- Update to this page (June 28, 2017) -- 
As Regular Reader Judith pointed out:  

"Floaters that appear gradually and are there all the time are nothing to worry about.  However, if there is a sudden increase of floaters, it may be a medical emergency as this can be the sign of a retinal detachment.
Anyone who experiences an onrush of floaters should see an ophthalmologist immediately."  

She's right.  If you normally do NOT see floaters, but all of a sudden see a bunch of new floaters, get yourself to a doctor.  

 Search Lessons 

A couple of lessons here.... 

1. Sometimes you must go deeper.  In Challenges 1 and 3, we had to do an initial search, then decide what to learn from our initial results (usually additional terminology) in order to do a better search that will get us to higher quality results.  Pay attention to the language used in the results you find.  Even if that particular result isn't of high quality, it might well give you a search term or two that you CAN use to improve your searches.  

2. Use medical terminology for medical queries (but be sure you know the right terms to use).  In the scotoma example, I used the term "head trauma" to improve the quality (and targeting) of my search.  As always, be positive those specialized terms mean what you think they mean.  (Use define and friends to verify that you really know those words.)  

Not to worry, my vision is fine.  (So far at least.)  Hope you enjoyed this small medical mystery! 

Search on! 

A slight delay of game...
26 June 2017 | 5:33 pm

Hi folks... 

I'll be back tomorrow to answer our SRS Challenge from last week.  (I forgot that I'd be speaking at a conference today, so today is full of preparations for that talk.)  

It's not all work, work, work though.  The conference is on a lovely beach.  Here's a picture from this morning's run. 

And here is the track of my run, as recorded by my phone's GPS tracker.  

As you might recall from an earlier blog post about the errors in GPS and maps, I really don't (yet) know how to run on water.  

But I'll be free to write up my thoughts tomorrow morning.  See you then! 

Keep searching... 

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