Thursday, November 29, 2012

Answer: Will the Plex be underwater?



Fast Answer:  This one is too close to call! 

This challenge is quite typical of real-world search tasks--you often can’t just plug in the search terms and hope to get an answer.  A little search chaining and data validation is required to answer a series of questions and link them together to find the answer.  

Let's start at the top.  I assume you know that “the Plex” refers to “the Googleplex,” the name of the main complex on Google’s campus in Mountain View.  

BUT... if didn’t already know that, you'd have to figure out what I meant first.  This would be step 1:

 [ the plex ] 

And from a quick scan of the SERP, you'll learn that "the Plex" is shorthand for "the Googleplex" (which is where I took the picture above).

It's also just one step from searching for either: 

[ the plex ]  

or 

[ Googleplex ] 

...and you can easily find that the Plex is at 37.422°N 122.084°W – plug that into Maps.Google.com and you’ll see our campus with that lat-long marker just outside the window from my office.  As you can see by the location of the Googleplex, you’ll see it’s pretty close to the waters of San Francisco bay.  So this possibility of flooding after a 10' rise is a real worry! 





Now you know WHERE to look.  

Next step—determine the elevation of our location in the Plex.  

There are a few ways to do this. 

1.  Look at a topographic map.  This is the classic way to look up elevations.  (By which I mean that it's the way I used to look up such information pre-Google.)  To do this these days, I first searched for: 

[ USGS maps ] 

which got me to USGS.gov -- after a click, I found their map locator page.  I plugged in the street address of the Plex and found there were a couple of options open to me--the "Palo Alto" quadrangle map or the "Mountain View" quadrangle.  I chose the 1997 "Mountain View" map and downloaded the 17Mb PDF file from USGS.gov  


Here I clipped out the relevant part of the USGS "Mountain View" quad and dropped a Google-style red pin where the Plex now is.  (This map wasn't updated to show the Googleplex buildings.) 

As you can see, the point of the pin is right between the red "9" (meeting 9 feet elevation) and the 10-foot contour line that I've marked.  

Of course, the data accuracy here LOOKS better than it really is.  While USGS is famous for measuring elevation accurately, the smoothness of the contour line implies a level of precision that's not really there.  It's probably quite close to correct, but let's keep looking for additional data sources.  

Another approach would be... 

2.  Find a tool to get the elevation.  A great general heuristic for these kinds of search questions (that is, when you're looking up data that someone else has a great deal of interest in) be sure to look for a tool (that is, a web-application) that already does what you're trying to do.  

To find another data resource, I did the query:  

[ how to find elevation ]  

This leads me to a number of different elevation tools, but a very nice one is at:    http://www.daftlogic.com/sandbox-google-maps-find-altitude.htm

Plug in the lat-long and find this spot is recorded as 12 feet above the mean sea level. 

What I like about this site is that they also show you the code for how THEY get the elevation.  (If you read the code, they use Google’s Maps API to ask for the elevation at that location, returning values in feet and meters.) 


3.  Use Google Earth.  I then remembered that Google Earth ALSO has a 3D model of the earth, and what's more, it shows you the elevation of the point you've selected at the bottom of the page!  Here you can see the exact location of our lat/long point (in the middle of the umbrellas and tables set out for lunchtime.  (The white lines are big, decorative beams, one of which is shown in the picture at the top of this post.)  And, as you can see, Earth puts the elevation at 13 feet.  

That's encouraging, but don't stop searching just because you found an answer you like!  

4.  Find a tool that models sea elevations.  I then realized that there are lots of people interested in modeling sea rise, so I thought I could find a tool that would give me that data directly.  To find such a tool, I started my search with:  

[ sea rise map ]

Again, several different tools appeared, so I looked at the one from Climate Central ( sealevel.climatecentral.org/ )  I navigated their UI and dropped in my lat/long to find their 


which suggests that it will be underwater.  (The photoimagery illustrates the part that would be submerged, including the Plex.  The part that's white is still high-and-dry.)  

On the other hand, a similar tool at Geology.com shows that we'd be on a peninsula with a rise of 3 meters (9.8 feet).  

http://geology.com/sea-level-rise/san-francisco.shtml  -- which (at 3m rise) shows that we’d be on a peninsula, just barely out of the water.  

The thing I like about THIS map is that the author explains the limits of the accuracy of his data set (a practice I find deeply encouraging—I wish more places would do this kind of thing).  See:  http://blog.firetree.net/2006/05/18/more-about-flood-maps/

This analysis suggests that ALL of these maps have a margin of error that's pretty big--certainly within the range of watery-ness for the Googleplex.  

And when you consider that "elevation" is defined as "height above the average high-tide and low-tide points in that region." it's pretty clear that this case is too close to call.  We have some measurements that put the Plex out of the water by 1 or 2 feet, while others say it's 1 or 2 feet underwater.  Since the tide will go in and out in this part of the Bay by +/- 3 feet, I'd say we'd better start developing that beachfront!  

(And luckily, FWIW, my house is at 25 feet elevation above the average sea level in the Bay.  I'll be good for a few more years.)  
______________________

Search Lessons:  There are multiple points to make here. 

1.  Data varies a lot.  As you can see from the four different sources we found 4 different elevations.  Sometimes this comes from genuinely different measurements, and sometimes it comes from handling the data in slightly different ways.  I doubt that the lat/long for the Googleplex cafeteria was actually measured carefully (at least in publicly available way--I'm sure some surveyors have done this), and so all measurements we see here are approximations.

2.  Looking for a data set with analysis tool is often a great way to start.  This is an important lesson--I often see people starting to collect the raw data to answer a question, and not realize that other people have already done all of that work... and done it far more extensively and carefully than they will.  I know it seems obvious--but ALWAYS check to see if the data you're trying to collect isn't already out there.  (But on the other hand, I find it's often incredibly valuable to spot check other people's data--if only to understand what the data issues are for yourself.)  

3.  Chaining search steps together.  If you already knew what "the Plex" was, that's one step you didn't have to do.  But if you didn't know that, you' d have to go look up what I meant by that phrase first, then look up the elevation.  This is a simple chain of length 2, but more complex tasks might require chains of 3, 4, or even 9 steps to get to where you want to go.  

______________________

So in the final analysis, the elevation of the Plex is somewhere between 9 and 13 feet.  But given the tides, it's probably right on the edge of a 10 foot sea level rise.  We don't need to pack our bags yet, but it's worth paying attention to the level of the water! 

Search on! 









2 comments:

  1. Dr. Russell, out of curiosity, how long did you spend on searching out your solution to the query? Do you think there would be a value to a Google [tool:?] type search shortcut (like time:, weather:, etc.) for web-applications?

    example:
    tool

    imho: a quake or tsunami will be a more imminent remodeler than sea rise (.01inch/year)... time will tell... how did GooNYC/Chelsea fare with Sandy?
    Sandy

    Any thoughts on diving the roller coaster?
    Seaside Heights

    ReplyDelete
  2. quick answers: I only spent a couple of minutes looking for the tools. (I figured there would be one or two.)

    And Google NYC did just fine, thanks for asking.

    I think I'll pass on diving the roller coaster. Looks astonishing, but probably a *little* dangerous out there.

    ReplyDelete