Dataset: GAL Hydrochemistry Formations QC for TDS v02 Surfaces



This dataset was derived by the Bioregional Assessment Programme. The parent datasets are identified in the Lineage field in this metadata statement. The processes undertaken to produce this derived dataset are described in the History field in this metadata statement.

This dataset contains raster representations of Total Dissolved Solid (TDS) measurement trends in groundwater samples for each hydrogeological formation in the Galilee Basin subregion.

The dataset also contains supplementary polygon Feature Classes for each formation, to be used in the visualisation of the rasters. For each formation this includes:

a) A rectangular data extent polygon feature class - created based on the distribution of data points for each formation and used to define the extent of the each raster

b) Data extent mask - further defines the extent of data distribution as well as the spatial extent of the formation, used to visualise the TDS trends for each formation only within the formation boundary and near the spread of point data.


Provides a visual representation for use in maps, of TDS measurement trends in groundwater for each hydrogeological formation in the Galilee Basin subregion.

Dataset History

The raster layers within this dataset were created using the 'Topo to Raster' interpolation method in ArcGIS. Topo to Raster uses an iterative finite difference interpolation technique. This method is preferred for map and visualisation purposes, especially in sparse data regions, as surface continuity is not compromised at a global level. This results in raster layers with smooth surfaces and trends for any level of data density, and surface continuity between areas of varying density.

Raster layers and polygon Feature Classes were created from the source point Feature Classes (dataset: GAL Hydrochemistry Formations QC for TDS v02 GIS - GUID: 109a21cd-a167-4320-84be-ab56cfc12cee)

Formation Data Extent polygons: An arbitrary rectangular polygon was created around the extent of points contained in each source point Feature Class

Formation Data Extent Mask: a hole was clipped from the Formation Data Extent polygon. The Eastern boundary of each hole was traced from the equivalent formation polygon found within the Galilee Groundwater Model, Hydrogeological Formation Extents v01 dataset (GUID: 5afbf7f1-1ee0-444b-9f77-dbad8d8de95b), while the western, northern and southern extent was defined by the distribution of point data or the Galilee subregion boundary (Bioregional Assessment areas v03, GUID: 96dbf469-5463-4f4d-8fad-4214c97e5aac).

Topo to Raster parameters

Input feature data = respective point feature class from source dataset

Field = TDS

Type = Point Elevation

Output cell size = 0.001

Output extent = Formation data extent polygon Feature Class

Smallest z value to be used in interpolation = smallest TDS value of input point Feature Class

Largest z value to be used in interpolation = largest TDS value of input point Feature Class

Drainage enforcement = NO_ENFORCE

Primary type of input data = SPOT

All other parameters left as default.

Dataset Citation

Bioregional Assessment Programme (XXXX) GAL Hydrochemistry Formations QC for TDS v02 Surfaces. Bioregional Assessment Derived Dataset. Viewed 11 April 2016,

Dataset Ancestors

General Information