(r6) DuckyInfoVisProjectProposal < Main

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---+ Ducky's <nop>InfoVis [[DuckyInfoVisProject][Project]] Proposal
[[http://www.cs.ubc.ca/~tmm/courses/cpsc533c-05-fall/projectdesc.html#proposals][Proposal specs]]


---++++++ Participants
Only me, Kaitlin Duck Sherwood, ducky@cs.ubc.ca

---++++++ Description
I plan to show U.S. population density with a zooming/panning interactive display.  I would use data derived from the 2000 U.S. Census.

I might need to restrict the dataset to some subset of the United States because of resource limitations.  I am not Google, and cannot store as much data as I suspect would be necessary to provide optimal performance.

There are all kinds of interesting and useful things that could be done on top of the base project.
   * I believe that once I am able to display total population density, then it is relatively easy to extend the code to allow displaying one of [[http://www.esri.com/censuswatch/sf1_ref.html][many different flavors of demographic data]], e.g. the non-white population.  I would like to do that, think I can probably do it, but hesitate to promise it.
   * Allowing the user to select information from one of several different censuses is also clearly within the realm of imagination.  I believe that this is slighly more ambitious (in part due to disk space limitations), and probably not within the scope of the class.


---++++++ Personal expertise: 
   * I did a project integrating maps, floorplans, and a virtual walkthrough about ten years ago at UIUC.  
   * I have investigated several maps/census schemes in the past 10 years, but never gotten past the exploratory stages.
   * I have never written anything in Javascript before, nor any dynamic client-side code of any kind, but would like to learn. 
   * I am not a graphics whiz.  I am not sure what algorithms to use to select what data is likely to be visible.  OTOH, I have Google and a copy of Foley and Van Dam within easy reach.
   * This could be a really cool project.


---++++++ Proposed solution
I plan to show U.S. population by rendering (on the fly, presumably) semi-translucent PNG images from the Census Bureau information that I would then overlay on Google Maps.

There are numerous opportunities for the performance to be inadequate.  Determining the right data to display for a given clipping region, retrieving the information, aggregating information (when zoomed out), rendering the PNG image, and serving the image all take time (in addition to the time Google takes, which I won't be able to control).  I expect that some caching and prefetching of data will be required.


---++++++ Scenario
Billy Rubin, a fifth-grade student at Rancho Cowabunga Middle School, is exploring population density as part of his urban housing presentation.  He goes to [[http://www.webfoot.com/gmaps/index.html][Webfoot's Information Visualization site]] and is presented with a what looks like a standard Google map of Palo Alto, CA.

---++++++ Interface mock-ups
@@@ illustrations of what the interface will look like 


---++++++ Implementation approach

I plan to use Javascript and the Google Maps API to serve maps, capture pan/zoom events, and to overlay area data on top of the Google Maps.

I plan to use the gd library, probably with a perl wrapper, to generate a transparent PNG image to overlay on top of the maps.

I plan to use C language [[http://shapelib.maptools.org/][Shapefile C library]] to parse a variant of the TIGER/Line data -- the [[http://shapelib.maptools.org/dl/shapefile.pdf][ESRI shapefile data]] -- which includes [[http://www.esri.com/censuswatch/sf1_ref.html][some population demographic information]].



---++++++ Milestones
 Include a list of project milestones with dates, breaking down the work into a series of smaller chunks.

Tasks (not milestones):
   * <strike>Figure out how to overlay one png on static map</strike>
   * <strike>Figure out how to overlay another png when map is recentered</strike>
   * <strike>Figure out if Google Maps can overlay maps fast enough.</strike>

   * Find good shapefiles
   * Develop a simple test suite for PNG manipulation 
   * Write code to create PNG from one known polygon extracted from shapefile; overlay on Google Maps
   * Write code to create PNG from several known polygons extracted from shapefile; overlay on Google Maps
   * Write code to create PNG from several known polygons, shaded with data from dBASE file; overlay on Google Maps

   * Given zoom level and map lat/long boundaries, figure out how to tell which polygons are visible
   * Write code to retrieve a polygon based on lat/long.
   * Write code to create PNG from lat/long boundaries at default zoom level
   * Figure out how to aggregate data from multiple polygons 
   * Write code to aggregate data
   * Modify code to create PNG from lat/long/zoom data
   * Overlay images dynamically on Google Maps

   * (aggressive) Add sliders to allow changing the parameters of the image (e.g transparency, hue)
   * (aggressive) Add radio buttons to change data sets
Topic revision: r6 - 2005-11-03 - DuckySherwood
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