GADDS runs the JetStream software package created by Intrepid Geophysics Pty Ltd. GADDS was implemented for web-data delivery of Geoscience Australia's land gravity and airborne survey datasets in both grid and (point/line) vector data formats. GADDS works on geodetic magnetic and gravity grids of continental Australia as well as individual survey magnetic, radiometric and elevation datasets. Gravity point data from Australia is extracted from an Oracle database. The GADDS front-end application was developed in-house at Geoscience Australia by Aaron Sedgmen.

Airborne electromagnetic (AEM) systems are increasingly being used for mapping conductivity in areas susceptible to secondary salinity, with particular attention on near-surface predictions (ie those in the top 5 or 10 metres). Since measured AEM response is strongly dependent on the height of both the transmitter loop and receiver coil above conductive material, errors in measurements of terrain clearance translate directly into significant errors in predicted near-surface conductivity. Radar altimetry has been the standard in airborne geophysical systems for measuring terrain clearance. In areas of agricultural activity significant artifacts up to five metres in magnitude can be present. One class of error, related to surface roughness and soil moisture levels in ploughed paddocks and hence termed the ?paddock effect?, results in overestimation of terrain clearance. A second class of error, related to dense vegetation and hence termed the ?canopy effect?, results in underestimation of terrain clearance. A survey example where terrain clearance was measured using both a radar and a laser altimeter illustrates the consequences of the paddock and canopy effects on shallow conductivity predictions. The survey example shows that the combination of the dependence of AEM response on terrain clearance and systematic radar altimeter artefacts spatially coincident with areas of differing land-use may falsely imply that land-use practices are the controlling influence on conductivity variations in the near surface. A laser altimeter is recommended for AEM applications since this device is immune to the paddock effect. Careful processing is still required to minimise canopy effects.

No abstract available

Mapping Mineralogical and structural relationships with satellite-borne ASTER and airborne geophysics at Broken Hill

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Simple, conceptual geomorphic models can assist environmental managers in making informed decisions regarding management of the coast at continental and regional scales. This basic information, detected from aerial photographs and/or satellite images, can be used to ascertain the relative significance of several common environmental issues, including: sediment trapping efficiency, turbidity, water circulation, and habitat change due to sedimentation for different types of clastic coastal depositional environments.

At this scale 1cm on the map represents 1km on the ground. Each map covers a minimum area of 0.5 degrees longitude by 0.5 degrees latitude or about 54 kilometres by 54 kilometres. The contour interval is 20 metres. Many maps are supplemented by hill shading. These maps contain natural and constructed features including road and rail infrastructure, vegetation, hydrography, contours, localities and some administrative boundaries. Product Specifications Coverage: Australia is covered by more than 3000 x 1:100 000 scale maps, of which 1600 have been published as printed maps. Unpublished maps are available as compilations. Currency: Ranges from 1961 to 2009. Average 1997. Coordinates: Geographical and either AMG or MGA coordinates. Datum: AGD66, GDA94; AHD Projection: Universal Transverse Mercator UTM. Medium: Printed maps: Paper, flat and folded copies. Compilations: Paper or film, flat copies only.

The Sitepics (abbreviated site pictures) directory contains 71 scanned pictures (as TIFF images) from various sources (mostly Mineral Resources and Energy Branch photographs, GA ferived, some PRL and tourist brochure photographs). The images include historical pictures, diagrams, photographs of mining, mined areas and mining equipment, photographs of 1997 orthophotography, photographs of rehabilitation, and some scenic pictures. Most are referenced by a hotlink to the theme photos.shp (clicking on the marker, geographically positioned, with the hotlink tool pops up the image). MREB welcome your feedback on the true site from where such photographs were taken so they can be more accurate positioned.