The calculated run-up height and resulting inundation ashore is determined by
the input topographic and bathymetric data, the forcing terms, the
initial and boundary conditions, as well as the cell resolution. It
would be ideal if the data adequately captures all complex features
of the underlying bathymetry and topography and that the cell
resolution be commensurate with the underlying data. Any limitations
in terms of resolution and accuracy in the data will introduce 
errors to the inundation maps as well as the range of model approximations,
including the cell resolution.

A number of sources have supplied data for this study. With
respect to the onshore data, the Defence Imagery and Geospatial
Organisation (DIGO) supplied the DTED (Digital Terrain Elevation
Data) Level 2 data which has been authorised for Australian Tsunami
Warning System use only. This data has a resolution of 1 second
(about 30 metres), produced from 1:50 000 contours, elevations and
drainage. The Department of Land Information (DLI) has provided a
20m DEM and orthophotography covering the NW Shelf. As the 30m
DTED Level 2 data is bare earth we have chosen to use this as
the onshore data set.

With respect to the offshore data, the Department of Planning and
Infrastructure have provided state digital fairsheet data around
Onslow. This data covers only a very small geographic area. (Note,
similar data has also been provided for Pt Hedland and Broome.) 
The Australian Hydrographic Office fairsheet data has also been utilised.

In summary,

\begin{center}
\begin{tabular}{|l|l|}\hline
Data & Detail \\ \hline 
DIGO DTED Level 2  & Onshore, 1 second $\approx$ 30m) \\ \hline 
DLI & Onshore, 20m DEM and orthophotography \\ \hline
DPI & Offshore, fairsheet data around Onslow \\ \hline
\end{tabular}
\end{center}

The coastline has been generated from the DIGO DTED Level 2 and modified
using the aerial photography and the two detailed surveys provided
by WA Department of Planning and Infrastructure. 

The extent of the
data used for the tsunami impact modelling can be seen in the
following figure.

\begin{figure}[hbt]

  \centerline{ \includegraphics[width=100mm, height=75mm]{onslow_data_extent.png}}

  \caption{Data extent for Onslow scenario. Offshore data shown in blue and onshore data
in green. The bounding polygon used for the simulation is shown in red.}
  \label{fig:onslow_data_area}
\end{figure}


Section \ref{sec:metadata} outlines the metadata for data used for
this study.