A Discussion of the Visualization Needs of the Community Carolina Environmental Program University of North Carolina at Chapel Hill A Discussion of the

Carolina Environmental Program University of North Carolina at Chapel Hill

A Discussion of the Visualization Needs of the Community

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



PAVE Smoothed Tile Plot Animation(courtesy RWDI)



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, polygons

e.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, …



PAVE Plotting Relative Difference (courtesy NC DNR)



PAVE Plotting Gridded Data and Observations (courtesy NC DNR)



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



GIS Example – ESRI ArcExplorer(Layers, Colored Thematic Map)



Color-based Thematic Map of Polygons(Courtesy LADCO)



Size-based Thematic Map of Point Sources (courtesy LADCO)



GIS-style Annotated Thematic Map of Gridded Data

(courtesy RWDI)



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)



Hourly Stacked Bar Chart(courtesy LADCO)



Bar Chart Plus Line(courtesy LADCO)



Vis5D Vertical Cross Sections, Terrain, Isosurface



Vis5D Spreadsheet



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



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



Display Requirements for“The 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)



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



Functional Requirements for“The 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



GIS-like Functional Requirements for“The 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 > 100 tons NOx / year or

find all grid cells with max ozone > 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



GIST QA of Point Source Inventory



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 didn’t get to that point



GIST: Query to Find Objects that Meet a Criteria, Show Results on Map or in Table



Visualizing Grids with MIMS Grid Family GUI



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



Unidata Integrated Data Viewer (from the IDV User’s Guide)



Unidata IDV Globe Display(from IDV Visualization examples)



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



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



Air Quality Forecast of Ground Level Ozone 1-hr average (courtesy NOAA)

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Spatio-temporal Estimated Data BMELib/Matlab Visualization

(courtesy Dr. Marc Serre, UNC Chapel Hill)



Point Data with PDFs and Computed Mean (courtesy Dr. Marc Serre, UNC Chapel Hill)



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 (< 3MB) to

[email protected])

Documents

A Discussion of the Visualization Needs of the Community Carolina Environmental Program University of North Carolina at Chapel Hill A Discussion of the