Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p79
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 79/117)
Character Range: 569897–572909

printing
Enlightens and arouses curiosity                                Graphic repels interest and obscures meaning

    (adapted from Langley 1993 and Tufte 1983)

14.4          Site plans
Site plans should be drawn to a scale appropriate to the size of the project and the level of detail required. Drawings on A3 or larger paper as foldouts or enclosures may be necessary. Plans should show:
    * a north-facing arrow
    * scale
    * lot boundaries
    * location of present and former infrastructure and site activities
    * distribution of fill types
    * locations of affected vegetation, stains, odours, chemical containers, etc.
    * direction of surface run-off and drainage
    * presence of above and below ground services
    * areas covered by an impermeable seal (e.g. concrete, bitumen and buildings).
In some situations, it may be necessary to show previous site layouts as overlays over the current layout and perhaps have another overlay of sample locations or show sample excavation boundaries (see Appendix D).

Figures showing topographical contours in relation to site features and sample locations can assist with the assessment of sites with varied topography/changes of level.

14.5          Presentation of contamination data
Sample locations, identification numbers, results and depths should be plotted on one or more site layout figures. Sites with a large number of sample locations and numerous elevated results can be difficult to fully comprehend and time-consuming to assess. Therefore, to minimise assessment times and to allow, at a glance, a clear representation of contamination issues associated with the site, site plans should be used to display sample results. For large and complex sites, 3-D visualisation software may also be useful.

Contoured figures and/or maps can be useful for illustrating the distribution and trends of contamination, however, the interpolation methods used, for example, kriging, regression, minimum curvature, etc. can influence the results. For this reason, contours should be interpreted with caution and figures should include labelled data points for clarity.

If there is 'too much' data available, this may be addressed by displaying only significant results on the map. However, this should be done cautiously as censoring some of the data can obscure trends. 'Normal' results can be important if elevated results were anticipated and may need to be displayed.

An alternative method is to display a subset of the data e.g. separate figures for metals and petroleum hydrocarbons or provide some form of surrogate measure of where contamination may occur on a site. A series of figures, each with a different analyte, can be useful in this situation.

The following techniques may be useful to clearly display results:
    * a separate site plan for each elevated analyte, which displays sample locations, sample identification numbers and depths, and shows different concentration ranges in different colours
    * a separate