Ducky's Info Vis Milestones

Status: currently working on changing the color table, not having much luck. Maybe there are two different color tables? Instead, figure out an encoding that can use three independent bytes, create an actual color, use that to look for exact color, munge that.

Warning: there are cout's and other hacked up stuff to test the color table stuff. Look for "TODO TODO". Or just diff with prev version.

AIs

• DuckyInfoVisPresentation
• look into changing the color table in PNG files with gd
  • http://www.boutell.com/gd/manual2.0.33.html#gd2format
• in report mention people that I got code from:
  • kodiak
  • maptiki guy
  • qstring guy (maybe not used)
• make test4.html dynamicly generated -- use window.location.search to get the query string
  • see qstring.html for how to get qstring
• use arg0 to determine where the min and max cutoffs are; link to all those
  • Some work done on that -- look for sh6.somestuffdone.html or something like that, also sh7.somealsj.cc
• make overlay transparency user-selectable with kodiak technique
  • make both maps respond to zoom changes

Current worries

• speed, speed, speed
• What are storage needs?
  • in Palo Alto, .005 degrees long for 500 pixels at max zoom in => 100,000 pixels / degree
  • in Palo Alto, .002 degrees lat for 300 pixels at max zoom in => 150,000 pixels / degree
  • US is about (-66 to -124) 58 degrees wide => 12,000 images wide (at 5K apiece)
  • US is about (32 to 48) 16 degrees tall => 8,000 images tall (at 5K apiece)
  • so at max zoom level, 96M images to cover the whole US * 5K => 480G
  • roughly powers of two as zoom out; 15 zoom levels before whole US fits (after that, it's just silly?)
  • so roughly 2*480G worth of space needed for whole US, or about 1000G
  • if it takes about 5 sec to render a little one =>

• What are units of areas?
• What if different browsers don't work? -- tant pis for now
• caching
• How do I deal with the huge dynamic range?
  • Offer several:
    • Which?
    • How does user switch between them?
• Do I allow people to change range on the fly?
• How do I capture clicks through the overlay (the map/satellite lens uh-oh does things differently).
• Speed speed speed
• LD_LIBRARY_PATH / static libraries nonsense

Ducky's Info Vis Tasks

• Explore different color bars
• Thoroughly understand and document how census bureau data fits together

• 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 population file; overlay on Google Maps

• Given zoom level and map lat/long boundaries, figure out how to tell which polygons are visible
  • test better
• Write code to create PNG from lat/long boundaries at one zoom level
• Write code to retrieve a polygon based on lat/long.
• Port code to Dreamhost
• Plug code into CGI
• Figure out how to redraw with panning
• Write code to deal with panning via controls
• Figure out how to drag the overlay (ulp, what if not possible?)
• Figure out how to aggregate data from multiple polygons -- maybe not needed?
• 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
• (aggressive) Allow user to choose from several different years of data
• (extremely aggressive) allow semi arbitrary data to be mapped
  • design with XML format
  • design interactive
  • find information about Mike Beckerle's data description language

Proofs of concept:

• simple walking duck
• two overlays
• overlay transparent Google Maps over Google satellite images

Promised milestones

• 4 November: Proposal finished
• 13 November: One PNG file generated with one polygon extracted from dataset, requiring:
  • extracting polygons with the Shapefile C library
  • extracting the appropriate demographic data from the dataset with the Shapefile C library and the data files
  • associating polygon <->demographic data
  • understanding the gd library well enough to generate a PNG with a transparent polygon
• 20 November: Functional panning, perhaps limited to one US state and perhaps slow, requiring:
  • determining which polygons will be visible given lat/long bounds
  • iterating through visible polygons, drawing each
  • plugging overlays into the Google Maps API
• 4 December: Functional zooming
  • determining which polygons will be visible given lat/long bounds and zoom level
  • aggregating lower-level data (note that I do not think this is trivial)
  • killing small code gremlins
• 11 December: Performance tuning and bug fixes done, probably requiring finishing:
  • pre-processing census bureau data into a form that is easier to extract quickly
  • prefetching of neighboring overlays
  • caching previously-used overlays
  • killing large code gremlins
• 16 December: Status update due, requiring
  • bibliography done
  • writing done
• 19 December: Final due date, requiring
  • learning LaTeX
  • coercing text into journal format
  • killing LaTeX gremlins

• Set ALLOWTOPICCHANGE = DuckySherwood