A Discussion of the Visualization Needs of the Community

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A Discussion of the Visualization Needs of the
Community Where do we go Next?

• Alison M. Eyth
• Carolina Environmental Program
• University of North Carolina at Chapel Hill
• October 29, 2003

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PAVE Smoothed Tile Plot Animation(courtesy RWDI)
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Currently Used Visualization Tools

• PAVE
• free to use, recently made open source
• tile plots and integrated time series plots
• supports 2D and 3D temporal varying gridded data
  and point observations
• supports animation and formulas
• GIS
• Free GRASS, ArcExplorer, OpenMap,
• License fees MapInfo, ArcView, ArcGIS,
  MapViewer,
• regular and thematic maps of data in points,
  lines, polygonse.g. geopolitical boundaries,
  roads, water bodies
• supports multiple layers of different data types
• Free tools Vis5D, NCAR Graphics, OpenDX, GrADS,
  FAST,
• Commercial tools SAS, Matlab, S-PLUS,

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PAVE Plotting Relative Difference (courtesy NC
DNR)
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PAVE Plotting Gridded Data and Observations
(courtesy NC DNR)
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Some PAVE Limitations

• Graphics are written in X-Windows / Motif (not
  good for PCs)
• Cannot plot data in lines or polygons only
  rectangular grid cells and limited capability for
  point observations
• Cannot incorporate GIS data such as population
  density or other interesting data sets into plots
• Cannot be executed over the Web
• Cannot animate over x, y, or z (only time)
• Only a few maps provided (states, counties,
  roads, rivers), with limited rendering styles
• Lack of support for 3D plots or contour plots
  with lines
• Must be compiled separately for each platform
• Difficult to maintain

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GIS Example ESRI ArcExplorer(Layers, Colored
Thematic Map)
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Color-based Thematic Map of Polygons(Courtesy
LADCO)
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Size-based Thematic Map of Point Sources
(courtesy LADCO)
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GIS-style Annotated Thematic Map of Gridded
Data(courtesy RWDI)
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Limitations of GIS

• Many are expensive for end users
• But GRASS and ArcExplorer are free
• Can be complicated to use
• Little support for time-varying or 3D model data
• Would need to be customized to read standard AQM
  data formats
• Limited (any?) support for formulas
• Animation capabilities very limited
• Few cross-platform options (usually they are
  either PC or Unix)

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Hourly Stacked Bar Chart(courtesy LADCO)
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Bar Chart Plus Line(courtesy LADCO)
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Vis5D Vertical Cross Sections, Terrain, Isosurface
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Vis5D Spreadsheet
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Can we Create The Ultimate Visualization Tool

• Combine the good elements from existing commonly
  used visualization tools into one ultimate
  visualization tool
• Goal Meet almost all the visualization needs
  within a single tool
• Many aspects of requirements for the tool
• Data
• Display
• Functional
• System

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Data Requirements for The Ultimate
Visualization Tool

• Read formats common to meteorological and air
  quality models
• direct AQM inputs and outputs (2D and 3D
  temporally varying gridded data, gridded boundary
  files)
• emission inventories (temporally varying point,
  line, and polygon data with attributes)
• Read inputs, outputs and observational data for
  other types of environmental models
• multimedia models, water quality models, plume
  models, irregular grid air quality models,
• Read and display maps/data from GIS files (e.g.
  Shapefiles)
• Geopolitical boundaries, water bodies, road
  networks, cities, land use
• Read DTED, satellite images, radar data, met and
  air quality observational data, flight paths with
  observations
• Read local and remote files
• Read very large data sets
• Understand 3-D and time varying data

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Display Requirements forThe Ultimate
Visualization Tool

• Present diverse types of data in an integrated
  display (2D 3D gridded, point, line, polygon,
  satellite, DTED, )
• Have round earth (global) and flat earth
  (projected) displays
• Standard and thematic maps for points, lines, and
  polygons
• Satellite, radar, (and other) image displays
• 3D displays e.g. Topography, multi-colored
  isosurfaces
• Line contours and color filled contours
• Color filled grid cells, continuously shaded
  gridded data
• Met displays Wind vectors, wind barbs,
  streamlines, Skew-t plots, met observations
• Integrated access to time series plots, bar
  charts, histograms, and other 2D charts from
  map-based plots
• Support multiple related display windows (with
  concurrent animation)
• Support for transparent colors (helps w/
  integrated display)

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System Requirements for The Ultimate
Visualization Tool

• Support both batch and interactive modes
• Run over the web and on desktops
• Run on Windows and Unix systems
• Manage memory appropriately to analyze very large
  data sets
• Save plots and animations to image files
• Facilitate creation of web pages for its outputs
• Print plots
• Easy to compile
• Easy to extend (e.g. to new data displays, data
  formats)
• Easy / intuitive to use

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Functional Requirements forThe Ultimate
Visualization Tool

• Animate through time and space (e.g. x, y, z,
  arbitrary plane)
• Select and plot subsets of data sets
• Probing to inspect data values / attributes (e.g.
  in tables)
• View slices of 4D datasets using various 2D
  displays (e.g. time series plots, x-t plots, bar
  charts, tile plots)
• Compute and plot results of formulas
• Perform data interpolation (e.g. point data onto
  a grid) plot
• Compute useful statistics about data
• Customizable plots (e.g. legend, colors, header,
  footer)
• Zoom, pan, rotate

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GIS-like Functional Requirements forThe
Ultimate Visualization Tool

• Support many map projections and earth ellipsoids
• Save / reload project so you can restart where
  you left off
• Provide overview map for zooming panning
• Query to find data objects that meet a criteria
  and analyze the attributes of or operate on
  resulting objects
• e.g. find all point sources emitting gt 100 tons
  NOx / year orfind all grid cells with max ozone
  gt 120ppb) and show on map or in a table
• Measure distances / areas along map and show
  scale of map
• Show coordinates of mouse pointer in lat-lon and
  projected coordinates
• Show data sets only at scales appropriate to the
  data set
• Label features with attribute data
• Show pop up tool tips based-on attribute data
• Find addresses on a map

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GIST QA of Point Source Inventory
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Geographic Information System Tool (GIST)

• Prototype developed at MCNC to explore features
  not available in PAVE
• Integrated display of point, line, and polygon
  data in layers
• Reads Shapefiles, extensible to read other data
  formats
• Creates standard and thematic maps
• Supports common map projection types
• Customizable plots wrt colors, shapes, line
  styles
• Probing to inspect attributes of data objects
• Querying of attribute data then map or see table
  of matches
• Show coordinates of mouse pointer
• Overview map, zoom, pan
• Java-based runs over web, on Windows / Unix
  without recompilation
• Easy to use
• Interactive mode only
• Had planned to support animated thematic maps and
  reading model data, but didnt get to that point

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GIST Query to Find Objects that Meet a Criteria,
Show Results on Map or in Table
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Visualizing Grids with MIMS Grid Family GUI
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MIMS Grid Family GUI

• Define and visualize a set of related grids
• View grids in conjunction with shapefiles of
  related data (e.g. counties, rivers, point
  sources)
• Support for creating fine grids nested within a
  coarse grid
• Supported map projection types are
  Latitude-Longitude, UTM, and Lambert conformal
• Grids defined by four dimensions lower left x
  y, upper right x y, dx dy, number of cells x
  y
• Specify three dimensions and compute fourth
• Can specify lower left upper right corners with
  mouse
• Java-based. Currently available with MIMS (see
  http//www.epa.gov/asmdnerl/mims)
• Write grids to / read grids from GRIDDESC files
  used by SMOKE and CMAQ

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Unidata Integrated Data Viewer (from the IDV
Users Guide)
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Unidata IDV Globe Display(from IDV Visualization
examples)
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Unidata Integrated Data Viewer

• New tool that supports most data requirements
• Data types include gridded data, Shapefiles,
  radar, satellite, observations
• Reads remote and local files
• Understands 3-D, time varying data
• Currently supports all display requirements
  except possibly polygon-based thematic maps
  (although time series could be improved)
• Global and flat 2D and 3D displays
• Animation over time and levels, data probes,
  Crude time series, vertical profiles,
  time-height, HTML viewer
• 3D displays Topography, isosurfaces
• Skew-t plots, contours, color filled contours,
  filled grid cells, continuously shaded gridded
  data, wind vectors, wind barbs, streamlines,
  surface met observations

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Unidata Integrated Data Viewer (ctd)

• Supports most basic functional requirements
• animation through time space
• subsetting, derived parameters, probing
• zoom, pan, rotate
• integrated time series other 2D plots
• May not support many GIS-like functional
  requirements
• Supports most system requirements
• Java tool based on VisAD
• Output as JPEG, quicktime movies, flythroughs
• Interactive analyses only right now, but
  considering batch mode
• Some support for running over web / creating web
  pages
• Available from http//unidata.ucar.edu

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Air Quality Forecast of Ground Level Ozone 1-hr
average (courtesy NOAA)
OZONE (parts per billion)
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Spatio-temporal Estimated Data BMELib/Matlab
Visualization(courtesy Dr. Marc Serre, UNC
Chapel Hill)
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Point Data with PDFs and Computed Mean (courtesy
Dr. Marc Serre, UNC Chapel Hill)
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Summary

• Currently available tools do not meet all
  visualization requirements for the UV Tool
• Unidata IDV comes close
• Need to consider how we can meet the remaining
  needs
• Visualization gallery was suggested to share
  ideas among community
• check CMAS web site for future details
• for now, e-mail candidate visualizations (lt 3MB)
  to eyth_at_unc.edu)