Geophysical Archive Data Delivery System Help

1. Step 1 - Access Window
• 1.1 Data Search
  • 1.1.1 Lat/Long Window
  • 1.1.2 Map Window
  • 1.1.3 Additional Layers
2. Step 2 - Data Type and Theme Window
3. Step 3 - Choosing datasets for download
   • 3.1 Introduction
   • 3.2 Raster Datasets
   • 3.3 Survey Extents
   • 3.4 Survey Metadata
   • 3.5 Vector Datasets
4. Field Name Definitions
5. Submit Request
6. Help Link

Accessing Geophysical Survey Datasets

Access to GADDS is via the URL, www.ga.gov.au/gadds/.

If you are having problems contact the Airborne Surveys Database Administrator at Geoscience Australia. Details are as follows:

Murray Richardson.

Telephone - 02 6249 9229.

or via e-mail - murray.richardson@ga.gov.au

Step 1 - Access Window

1.1 Data Search

The access window allows the user to define the area of interest. The page opens with the Australian coastline theme active (this layer cannot be turned off). The user can add themes by selecting them from the list of check boxes on the right of the page.

Basic navigation is done using the four buttons to the right of the map of Australia - zoom in, zoom out, pan and query (Figure 1).

There are three ways to search for geophysical datasets. Either:

Use the Lat/Long Rectangle or the Map Sheet Index window (right) side of the screen.

Or

Use the Map window (left) side of the screen.


Figure 1. Geophysical Data Delivery System Lat/Long Rectangle and Map window.

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1.1.1 Lat/Long Window, Map Sheet Index (Right) Side of Screen

Search co-ordinates can be entered in the fields supplied (nb: latitudes are negative in the southern hemisphere).

Or select the name of a 1:250k Map Sheet from the drop down list to search for datasets covering that sheet.

Once the area of interest has been defined press Proceed to Download to proceed to step 2.

A new window will open.

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1.1.2 Map Window (Left) Side of Screen

This window enables you to select datasets by dragging a box with the mouse over the area of interest on the map. You can use the navigation keys of this window to define a search area. Notes on the function of each navigation key will be displayed when the mouse is moved over the keys, they include:

• Zoom in: drag a box to zoom in.
• Zoom out: click to zoom out.
• Pan: click to recentre the map
• Query: drag a box to select the area for which you want data.

Once the area of interest has been defined press Proceed to Download to proceed to step 2.

A new window will open.

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1.1.3 Additional Layers

The check boxes under the Additional Layers heading allow for display of the following layers on the map of Australia

• Digital Elevation - A raster image of terrain (blue low, red high)
• Magnetics - A raster image of magnetic anomalies (blue low, red high)
• Gravity - A raster image of gravity anomalies (blue low, red high)
• Geological Regions - Major geological divisions
• Population Centres - Major population centres
• Roads - Major roads network
• Railways - Major railways network
• 1:250 000 map sheets
• 1:100 000 map sheets

Note:The population, roads and railways layers will only display when the map is displayed at less than 1:3 000 000 scale.

All other layers display at all scales.

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Step 2 - Data Type and Theme Window

The Data type and theme window displays the geodetic coordinates selected and allows for selection of the data type (grid or vector) and theme (magnetics, radiometrics, elevation, gravity) from the drop down lists (Figure 2).


Figure 2. Data Type and Theme window.

Select the datatype and theme then press Next to proceed to step 3.

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Step 3 - Choosing datasets for download

3.1 Introduction

This page displays all the datasets that meet the area of interest,data type and theme criteria (Figure 3).


Figure 3. Choosing gridded datasets for download.

3.2 Raster Datasets

Gridded datasets can be previewed by clicking on the Preview image link displayed under Additional Information at the bottom of each dataset (Figure 4).


Figure 4. Previewing gridded datasets.

In the image window a link vis62223.gif is displayed. Clicking on this link with the right mouse button enables the image file (in gif format) to be saved to the customer's hard drive using the Save Target As... option.

When downloading gridded datasets the Download this grid check box must be ticked. Datasets not required should not have a tick in the download check box.

For each GRID dataset selected for download there are three choices for the resolution of the supplied dataset:

• Get all data (approximate size of file in Kb)
• Subsample - get every 2nd grid cell (approximate size of file in Kb)
• Subsample - get every 10th cell (approximate size of file in Kb)

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3.3 Survey Extents

The survey extents of each dataset can be displayed by clicking on Survey extent. A new window is opened with the selected survey area coloured in red (Figure 5). Click on Close window to exit this feature.


Figure 5. Previewing survey extents.

For datasets at a national scale this feature is not available and National scale dataset. No survey details available will be displayed.

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3.4 Survey Metadata

The survey metadata of each dataset can be displayed by clicking on Survey metadata. A new window is opened with all available metadata relating to that survey displayed (Figure 6). Click on X in the top right corner of this window to exit this feature.


Figure 6. Viewing survey metadata.

For datasets at a national scale this feature is not available and National scale dataset. No survey details available will be displayed.

Select the radio button of your choice then press Next to proceed.

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3.5 Vector Datasets

For each VECTOR dataset selected for download the dataset is supplied at the full dataset resolution.

Click on the required check boxes to select the columns required from each vector dataset selected.

This page displays all the datasets that meet the area of interest,data type and theme criteria (Figure 7).


Figure 7. Choosing vector datasets for download.

Datasets meeting the selection criteria are ordered in decreasing order of data file size.

A percentage coverage estimate is given to indicate how much of the chosen dataset is in the region of interest.

In Figure 7, the area of interest covers 0.1 degrees north-south and 1.5 degrees east-west. This slice is approximately 8% of the Dubbo magnetic point-located dataset.

Datasets to be downloaded must have the Download the dataset vector checkbox displaying a tick.

A note is displayed indicating that to select all fields of the dataset leave all field check boxes unchecked.

If a subset of fields is required select the field of interest by clicking on the check box next to the required field.

Definitions of all field names is given in the next section of this help file.

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4. Field Name Definitions

Each vector dataset has standard fields that are listed for each dataset.

For magnetic data these fields are listed and defined in the following table:

Field names for magnetic datasets and their meaning

Field Name	Definition
altitudeMean	Nominal survey altitude in metres above sea level
bearing	Nominal line or tie bearing in degrees (0-359) measured east of true north
dateCode	Date line or tie was acquired - yyyymmdd
FID	Fiducial at sample in data record
fidFactor	Fiducial size in seconds (Factor to convert fiducial increment into seconds).
flight	Flight number for line or tie
groundClearance	Nominal survey altitude in metres above ground level
latitude	Latitude in degrees
LINE	Unique line or tie number
longitude	Longitude in degrees
microlevelled	As for residual and also microlevelled
residual	Levelled total magnetic intensity - IGRF + 5000nT
survey	Unique survey number identification
timeOfDay	Time of day at fiducial zero in seconds
gridflag	Gridding flag 1=ignore, 0=use. Indicates whether the data point was used in grid generation

For radiometric data these fields are listed and defined in the following table:

Field names for radiometric datasets and their meaning

Field Name	Definition
altitude	Altitude in metres above ground level of survey aircraft
altitudeMean	Nominal survey altitude in metres above sea level
bearing	Nominal line or tie bearing in degrees (0-359) measured east of true north
dateCode	Date line or tie was acquired - yyyymmdd
FID	Fiducial at sample in data record
fidFactor	Fiducial size in seconds (Factor to convert fiducial increment into seconds).
flight	Flight number for line or tie
groundClearance	Nominal survey altitude in metres above ground level
latitude	Latitude in degrees
LINE	Unique line or tie number
longitude	Longitude in degrees
potassium	Potassium (counts/sec OR pctK)
survey	Unique survey number identification
thorium	Thorium (counts/sec OR ppmTh)
timeOfDay	Time of day at fiducial zero in seconds
totalcount	Total count (counts/sec OR nanoGrays/hour)
uranium	Uranium (counts/sec OR ppmU)

For elevation data these fields are listed and defined in the following table:

Field names for elevation datasets and their meaning

Field Name	Definition
altitudeMean	Nominal survey altitude in metres above sea level
bearing	Nominal line or tie bearing in degrees (0-359) measured east of true north
dateCode	Date line or tie was acquired - yyyymmdd
FID	Fiducial at sample in data record
fidFactor	Fiducial size in seconds (Factor to convert fiducial increment into seconds).
flight	Flight number for line or tie
ground	Ground elevation in metres above sea level
groundClearance	Nominal survey altitude in metres above ground level
latitude	Latitude in degrees
LINE	Unique line or tie number
longitude	Longitude in degrees
plane	Aircraft elevation in metres above ellipsoid
survey	Unique survey number identification
timeOfDay	Time of day at fiducial zero in seconds

For gravity data these fields are listed and defined in the following table:

Field names for gravity datasets and their meaning

Field Name	Definition
project	Survey number unique to each survey
obsno	Oracle database generated unique number
stationno	Station number (includes project number)
stationname	Name of station
stationtype	Type of station eg. absolute, base, control, ground, helicopter etc.
dlong	Longitude
dlat	Latitude (negative) for the southern hemisphere
posunits	Position units (degrees, decimal degrees)
acc_loc	Estimate of accuracy of the position, in metres
datum	Position datum
spheroid	Spheroid used defined by the datum
posmethod	Method used to position the station eg. digitised from map, GPS, etc.
elevation	Elevation of ground at the station (metres above sea level)
elevunits	Units of the elevation
acc_ht	Estimate of accuracy of the elevation, in metres
elevdatum	Elevation datum
elevmethod	Method used to define elevation eg. barometer, map, GPS, etc.
elevtype	Elevation description eg. land, marine, underground etc.
obsdate	Date observation was made
countryid	Country observation was made in eg. Aus., PNG etc.
grav	Observed gravity value
gravunits	Units of the observed gravity
acc_gu	Estimate of the accuracy of the observed gravity
gravdatum	Observed gravity datum
calcdate	Date gravity data were processed
gravmethod	Gravity meter used eg. LaCoste-Romberg, Scintrex etc.
gmeterid	Gravity meter serial number
height	Height of the gravity meter at the observation point
heighterror	Estimate of the accuracy of the meter height
heightmethod	Method used to obtain the height of the meter
tc	Terrain correction
tcerror	Terrain correction accuracy estimate
tcmethod	Method used to calculate the terrain corrrection eg. Hammer hand, Intrepid software etc.
tcdensity	Density used in the terrain correction
confid	Confidentiality status of the station eg. open or embargoed
reliab	Estimate of the overall reliability of the reading (0 = unreliable, 7 = high reliability)
status	Status of the station (original or active)
comments	Comments made when observing the station
parent	Shows either '-1' for the original version of the station that has been converted, or the obsno of the station from which it has been converted
freeair	Free Air Anomaly value
bouguer	Bouguer Anomaly value at 2.67 tonne/cubic metre

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5. Submit Request

The final step in the procedure is to acknowledge reading and agreeing with the terms of the data licence and privacy statements (Figure 8).


Figure 8. Customer details.

Supply your name and contact details. The supplied e-mail address is the address for delivery of the requested data.

An estimate of the unzipped file size and the estimated time required to complete the request is also displayed.

A warning is supplied if the size if the requested dataset is greater than 200 megabytes. Files larger than 200Mb could take a long time to download on a slow internet connection.

Note: Files to be downloaded are restricted to be less than 200 megabytes in size.

For requests of datasets larger than 200 megabytes please contact Murray Richardson via e-mail murray.richardson@ga.gov.au or telephone him on (02) 6249 9229.

Click Submit Form and the user will be informed that the data request has been submitted (Figure 9).


Figure 9. Submitted request window.

When the data has been extracted and zipped you will receive an e-mail with a link to the prepared data.

The delivered e-mail will appear like the example in Figure 10.


Figure 10. E-mail indicating successful completion of data request.

Click on the link to the prepared data and select the Save this file to disk option (Figure 11). Click OK.


Figure 11. Saving the zip file containing the requested datasets.

The Save As window opens (Figure 12). It is recommended that at this stage the zip file is given a name representative of the contained dataset. Click Save.

Selecting the Open this file from its current location radio button will open the zip file as shown in Figure 14.


Figure 12. Saving the zip file to your hard drive.

The download will commence and when completed the zip file can be opened (Figure 13).


Figure 13. Download completed message.

Clicking on open will display the contents of the zip file (Figure 14).


Figure 14. An example of the contents of the downloaded zip file.

For all datasets the zip file will contain copyright information in the file Copyright_Disclaimer.txt

For gridded datafiles the filename convention is to have the airborne survey project number (Eg P569) and the dataset theme (Eg tmi for magnetics). The small g indicates a geodetic dataset is stored in the JetStream data directory

Two files are supplied when choosing gridded datasets. The gridded datafile and the associated header with a .ers extension

For vector datafiles the filename convention is to have the airborne survey project number (Eg P596) and the dataset theme (Eg MAG for magnetics)

Three files are supplied when choosing vector datasets. The '.dat' file contains the vector dataset. The '.des' file contains dataset datum and projection information. The '.dfn' file contains dataset field name definitions and formats.

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6. Help Link

If you are having difficulty searching for surveys, press the Detailed help link located on each page of GADDS to display these notes on how to use GADDS.

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