BROWSER – a tool for time-series exploration

Introduction
BROWSER Interface
Using BROWSER
Conclusions
References

Download Browser V1.24 (1,450KB)
Browser1_24.zip

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Latest Updates

A new version of Browser is currently being developed, and is expected to be ready for beta testing by Christmas 2004. Significant changes have been made to the structure of Browser. The standard conversion between daily-monthly, monthly-yearly has been removed. Now the user will be able to define their own transformations, ie. daily-weekly, daily to moving-average or something more complicated. Default conversions will be provided, but the user will be able to create their own if needed. Support is proved for several new formats including "netCDF" and SWAT model outputs. A GIS interface is also included to manage the datafiles.

Introduction

BROWSER is a tool for visually exploring time-series data (Figure 1) from various model outputs and formats located in different directories on a computer system or network. Data-series can be viewed separately, overlayed or stacked and can be accompanied with simple graphical statistics. The user can “zoom” into particular regions of charts and can “pan” or “scroll” through large data sets using a variety of controls.

BROWSER was developed to provide a simple and flexible graphical means to support exploration of modelled output of time-series data. Unfortunately this feature is usually inadequate or missing in most models, many of which are still “DOS-based. It is currently compatible with fourteen different file types including output from PERFECT (Littleboy et al. 1992), IQQM (DLWC 1998), APSIM (McCown et al. 1996), and SILO (Jeffrey et al. 2001, http://www.dnr.qld.gov.au/silo) models as well as four simple user templates. Other formats can easily be accommodated for in future versions.


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Figure 1: BROWSER interface showing the charting region with "tiled-view" for exploring time-series data.

BROWSER is written in c++ for the Windows operating systems (Win95, 98, NT, 2000 and ME) using Borland’s Visual Class Library (http://www.inprise.com). Charting is undertaken using Steema’s TeeChart component (http://www.teechart.com).

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3. BROWSER Interface

The BROWSER interface is composed of three main components; a file database, an open data-series selector and a charting region. The database and charting components are available as separate views toggled by the user, while the data-series selector is available at all times although it can be hidden.

Commands are available to the user though toolbar buttons, popup menus and through the main application menu. Toolbars are located along the left hand side of the application window and can be hidden.

Output can be printed or exported in “Enhanced Windows Metafile” and “Bitmap” formats.
 

3.1  Database

BROWSER incorporates a file database (Figure 2) to track model output files that may be stored in different locations on a computer system or network.

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Figure 2: Database interface with file preview

Creating the database involves defining parent directories, which are automatically searched (including subdirectories) for compatible files. The user can modify the database search criteria to recognise particular files. These files will be assumed to be of the form of one of the four user templates.

The database can be rebuilt using the “refresh” option to locate any new files or to remove any deleted files in the database directory list. New directories can be added at any stage and particular files or subdirectories can be excluded from the search.
 

3.2  Data-series Selector

After opening a file from the database, the tabulated data are converted into graphical data-series and are listed in the data-series selector on the left hand side of the application window.

The data are grouped together under the header of their parent file type, or through a common data type (such as rainfall, runoff etc) depending on user preference.

The user is able to show/hide data-series by clicking on its name in the data-series selector. Entire groups of data can be toggled on or off. Editing data-series line properties is achieved by clicking on the line icon next to the series name.
 

3.3  Chart Output

The power of BROWSER lies in the simple manner in which the user can manipulate the way that the data is presented. Data-series can be viewed separately or overlayed on top or above other series. The user can “zoom” into particular regions of charts and can “pan” or “scroll” through large data-sets using a variety of controls. Time series can be animated under mouse control, thus displaying the dynamic nature of model function. Data-series can automatically be viewed as daily, monthly, and yearly values.

Three main views are presented to the user: 

  • a “tiled-view” (Figure 1) presents each data-series in its own separate chart;
  • an “overlayed-view” (Figure 3) shows several data-series overlayed on a single chart; while
  • a “stacked-view” (Figure 4) places each data-series one above another on a single chart.
These views are further enhanced by the ability to locate each data series on its own vertical axis with automatic data range (auto-axes) or to use a single common vertical axis based on the maximum and minimum values of all visible data-series (max-axes).

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Figure 3: "Overlayed-view" with period shader visible

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Figure 4: "Stacked-view" of  interface

Zooming into and scrolling (panning) around the charts can be achieved though direct interaction between the mouse cursor and the charts:

  • zooming requires tracing a rectangle onto the chart while holding down the left mouse button, and
  • acrolling requires moving the mouse cursor around the chart with the right mouse button held down.
The charts are synchronised so that if one chart is “scrolled” or “zoomed”, the others are updated accordingly.

A unique feature of BROWSER is the “period-setter” tool (Figure 5) consisting of a timeline-like scrollbar allowing the user to change the viewing period, scroll through the data range or quickly jump to a particular period in the data range. This can represent a  “pseudo-animation” of chart data along the timeline. Advanced features of this tool allow precise adjustment of scrolling and zooming parameters.


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Figure 5: "Period-setter" tool in "advanced-mode"

“Double-clicking” on any chart will temporarily enlarge that chart to the full window area for closer analysis. Selecting any other series from the data-series selector or “double-clicking” the chart again will restore the view back to its previous layout.

Readability of the output is enhanced using a “period-shader” tool (Figure 6) through its ability to highlight areas of the chart background representing annual periods of interest and show the corresponding “year-label”. For example, the August to November period could be shown for each year, or a twelve-month period could be highlighted for alternate years.


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Figure 6: "Period-shader" tool showing options

Summary statistics of the time-series data including maximum, minimum, median, mean, 25th percentile and 75th percentile can be presented as a line series or a box plot (Figure 7), and can be superimposed behind its corresponding data-series (Figure 9).


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Figure 7: Summary statistics output (box-plot option) in "Tiled-view" layout

Finally, BROWSER has three options available to create new data-series from existing series:

  • the “Combine Series” option allows addition/subtraction of multiple data series,
  • the “Scatter Plot” (Figure 8) option creates a separate scatter plot from two data-series, and
  • the “Create Cumulative” option converts single data-series into a new cumulative plot.

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Figure 8: "Scatter Plot" created from two open data-series

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4. Using BROWSER

The range of predefined chart options in BROWSER allows several different tasks to be undertaken.

The “tiled-view” allows quick visualisation of each data series to locate obvious abnormalities or features and aids in selecting relevant data series for further investigation.

The “overlay-view” is useful for comparing both trends and magnitudes between data series. Trends are most easily analysed using the “auto axes” option so that each series has its own separate vertical axis while remaining in the same vertical screen space.  Using the “high axes” option allows direct comparison of the magnitude of data using a single vertical axis. However, one disadvantage of this view is that the chart region tends to get a little “cluttered” when too many series are selected, especially when the “auto axes” option is used.

The “stacked-view” alleviates much of the “clutter” of the “overlay-view” while still allowing a clear comparison of trends. Comparing magnitudes is less clear however as each series is now in its own vertical screen space.

The ability to superimpose a data-series over its statistical summaries (Figure 9) provides an efficient method for identifying abnormalities or outliers in an individual data-series. Combined with the advanced navigation features of BROWSER, the user can quickly scan through a time-series investigating how local events compare to the historical measures.


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Figure 9: Close-up of a data-series superimposed over a monthly-box plot statistic

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5. Conclusions

BROWSER is a tool for visually exploring time series data in a simple and efficient manner.  While BROWSER does not do anything that can’t already be done with an “off-the-shelf” package, the efficiency with which data can be explored, and relationships examined makes the task more attractive.  Pseudo animation brings data alive to novices and specialists alike.

It is planned that BROWSER will be readily available as a gesture to encourage enlightenment and transparency in the modelling world.

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6. References

Littleboy, M., Silburn, D.M., Freebairn, D.M., Woodruff, D.R., Hammer, G.L. and Leslie, J.K., Impact of soil erosion on production in cropping systems. I. Development and validation of a simulation model. Aust. J. Soil Res., 30:757-74, 1992.

NSW Department of Land and Water Conservation (DLWC), Integrated Quantity Quality Model Reference Manual, 1998.

McCown, R.L., Hammer, G.L.  Hargreaves, J.N.G.,  Holzworth, D. and Freebairn,  D.M., APSIM:  A novel software system for model development, model testing, and simulation in agricultural systems research. Agric. Systems. 50:255-71, 1996.

Jeffrey, S.J., Carter, J.O., Moodie, K.B., Beswick, A.R. (2001) Using spatial interpolation to construct a comprehensive archive of Australian climate data", Vol 16/4, pp 309-330, 2001 Environmental Modelling and Software. (Scheduled publication date May 2001)

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Project Members

David McClymont

David Freebairn

Yahya Abawi

Participating Bodies:

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APSRU, Department of Natural Resources and Mines,
PO Box 318, Toowoomba 4350, Queensland, Australia

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Queensland Centre for Climate Applications, Department of Natural Resources and Mines,
PO Box 318, Toowoomba 4350, Queensland, Australia

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National Centre for Engineering in Agriculture,
University of Southern
Queensland,
Toowomba 4350, Queensland, Australia

Download BROWSER (Version 1.24):

Browser1_24.zip

View Compatible Formats