Week 12

Dynamic Data & Animation



Dynamic Data

The data being analyzed may not be a static database - it may be a constantly flowing stream of data that you are dipping into to look at the current state at this instant.

There is a wide variety of data and tasks here:

Importance of context


Often very important not just knowing the current value (e.g. position, price) of an entity, but also the recent values of that entity, to show how it is changing (e.g. value increasing or decreasing, moving N / S / E / W, etc)


How do the characteristics and recent history of this entity compare to other similar entities (airplanes, currencies, stocks, etc) at the current time? Is there a larger pattern or is this one an anomaly.


How do the characteristics of the current data compare to the expected / common / average / historical data?
Google Finance is a nice example - lets see how apple is doing: http://www.google.com/finance?q=NASDAQ:AAPL
and how they compare to other tech companies and US stocks in general.



If you are working in shifts then its very important to effectively hand off control to someone else (air traffic controllers, nurses.) What is the current general situation? What are the points of interest that someone should keep track of?



How can the visualization draw the viewers attention to a new important event? (from Schneiderman)
It can be helpful to put these under user control so the user can set the thresholds or manually label interesting entities.

If the alert is very important then the visualization should continue trying to get the user's attention until he/she acknowledges the event.




in situ visualization

a nice paper on this topic is:
In-Situ Processing and Visualization for Ultrascale Simulations, Kwan-Liu Ma, Chaoli Wang, Hongfeng Yu, Anna Tikhonova, Journal of Physics: Conference Series 78 (2007)

As well as monitoring complex systems in the 'real world' there is also a need to monitor what is going on in high-performance simulations. Visualization is usually done as a post-processing step once the simulation has finished running. This is becoming less common today as there is now a need to do visualization while the simulation is running.Computer simulations take up a tremendous amount of resources and time (days to weeks) and the investigators don't want to waste them.


Simulations are now running at the peta scale with exa scale machines on the drawing board - http://en.wikipedia.org/wiki/Supercomputer#Timeline_of_supercomputers


Often simulations are run in emsembles with slight variations in the initial parameters to see what the different results are. If one of these simulations starts behaving incorrectly or goes out of bounds then it would be better to end it quickly and devote the processors, storage, etc to a set of parameters that may give a better result. Scientists would also like to 'steer' these simulations to particular points of interest while they are running. This means we need to see what is happening as the simulation is running - as Larry Smarr puts it 'the window in the oven.'

The ability for simulations to generate data far exceeds our ability to store that data, and storing data to disc can take a very long time. Most of the data generated in high-performance simulations is not stored, so you typically do not have the ability to look back through the various time steps of the simulation - the data for the current step is used to get to the next step and then it is discarded.

One approach to this is to stop the simulation at a given time step, move the relevant data over to another cluster for visualization, and then start the simulation running again. This allows the creation of the visualization to run in parallel (co-processing) with further computation. When the visualization is finished then decisions can be made on whether to continue the current simulation, refocus it by changing some parameters, or end it. This is doable but there can be a lot of time spent moving data between the clusters.

Another approach (in situ visualization) is to share the processing nodes and storage space on the same cluster with part of the cluster devoted to computation and part devoted to visualization. This is harder to code since the computation and visualization need to make sure they don't step on each other's data, and scientists often want to devote as much of the cluster as possible to computation. To reduce data duplication and movement the visualization code needs to accept the organization of the data for the simulation, which may be less than ideal. For this to work well the visualization software designers must work closely with the simulation software designers. This also means the visualization people need to make use of the resources on the simulation machine which typically means software-based rendering rather than hardware-accelerated rendering.

In both cases a major issue is the amount of data that needs to be moved. Data reduction techniques may involve only visualizing every n'th time step, visualizing all the data at a very course resolution, reducing the dimensionality of the data to be visualized, or focusing on a particular region of the simulation.





We talked about weather data before, and similar data on air quality is made available on an hourly basis.


Flight tracking software is a good example of this - when I was collecting data for the O'Hare project I grabbed the current data at regular intervals. There is similar data for buses in Chicago , and many other types of vehicles. This kind of data tends to be rather small though, there may be many entities.

We looked at the Chicago traffic data in graphic form when talking about uncertainty:
http://www.travelmidweststats.com/GCMLink.aspx?GCMLinkID=IL-TESTTSC-264

Similar charts can be useful when looking at things like electricity demand and will likely become more ubiquitous as we move to 'smarter' power grids:
http://www.caiso.com/outlook/SystemStatus.html


Back to Chicago traffic

We can also look at in a map form and that form may be better to show recent accidents or lane closures that explain why travel times have suddenly changed and give more accuracy as to where those events may have occurred (i.e. where the road turns from red to green.) Google maps and other services also nicely update the colour of tracked road in something close to real-time. Here are the traffic conditions around UIC on Monday Nov 2nd at 3pm. In the future fixed sensors communicating to a central server will likely be replaced by auto to auto communication systems for more timely communication.

Google Maps showing
      traffic around UIC

Other sites allow you to track individual entities:

Exploratorium's Cab Tracker: http://cabspotting.org/client.html
The live tracking is no longer being updated but the movies are still there

CTA Bus Tracker:
http://www.ctabustracker.com/bustime/map/displaymap.jsp

CTA Bus Tracker - Halsted

and slower things like whales:



or fast things like the international space station - http://spaceflight.nasa.gov/realdata/tracking/index.html or http://www.n2yo.com/?s=25544




Its pretty common for people to visualize the current state of their computer (CPU, network, battery, temperature, etc.) In the 'old days' of the 70s and 80s you could listen to the hard drive or the modem and know what the computer was doing. Today the computer helps out through sensor data or monitoring software.



back to the chaos that is twitter:
http://trendsmap.com/



somewhat slower:
reasonably current national air quality data - http://airnow.gov/
and an example at the state level - http://www2.des.state.nh.us/airdata/ and http://www.maine.gov/dep/air/ozone/currentdata.html

realtime (within 5 minutes) earthquakes for the past 7 days on Google earth
http://earthquake.usgs.gov/earthquakes/feed/v1.0/
and a map version http://earthquake.usgs.gov/earthquakes/map/

local 'weather' data in EVL: http://www.evl.uic.edu/aej/TEMPS/evlTempF.html

internet traffic report: http://www.internettrafficreport.com/



on the financial side there is a lot of work looking at the current state of the stock market and currencies. In many cases these are purely algorithmic since fractions of a second can be important in making those kinds of trades, but people also use visualization to look for trends or opportunities that the algorithms may have missed.

For example aqumin's AlphaVision: https://sites.google.com/a/aqumin.com/wiki/





Animations


Animations can be an end product of an analysis, and it can also be used within a visualization and analysis tool as we have seen in the class projects.

Animation allows us to look at the pace of change in the data (velocity), and changes in that pace (acceleration.) In visualizations with many entities it helps us follow the path of individual entities rather than just seeing 'snapshots' of static positions. In many cases the original phenomena being studied was continuous but was discretized when it was sampled / measured so animation can bring us back to a more 'natural' representation of the information. One must be careful that any interpolation done for an animation remains true to the original data.


In terms of the lie factor, here you need to be careful of how time appears to progress. You should have an indication of the current time, and you should not change the speed that time passes or cut out sections of time without informing the viewer in an obvious way.


A nice application showing global statistics over time
http://www.gapminder.org/

There is a nice 20 minute 2006 TED talk about it here: http://www.ted.com/talks/hans_rosling_shows_the_best_stats_you_ve_ever_seen.html
and there are several more video talks with Hans Rosling that are worth watching as well, one shorter more recent one is http://www.youtube.com/watch?v=jbkSRLYSojo

Some nice examples:

CodeSwarm out of UC Davis - http://vimeo.com/3914346
and an example with twitter - http://vimeo.com/9225227

similar to the data from the O'Hare project, here are
airplane flight patterns across the US - http://youtube.com/watch?v=dPv8psZsvIU
and worldwide http://www.youtube.com/watch?v=1XBwjQsOEeg


more data is available here: http://www.aaronkoblin.com/work/flightpatterns/

an interesting ad: http://flowingdata.com/2009/07/29/animated-infographics-for-the-eat-local-eat-real-campaign/


Here is a flash visualization of the Chicago Fire of 1871
http://www.pbs.org/wgbh/amex/chicago/maps/pop_fire_body.html


NASA Goddard Space Flight Center makes some very nice high resolution animations:
http://svs.gsfc.nasa.gov/

including the 2005 hurricane season animation - 27 storms
http://svs.gsfc.nasa.gov/vis/a000000/a003300/a003354/index.html


Coming Next Time

Viewer's Choice Presentations


last revision 11/9/15