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Fields:

Keyword:

Vertical Accuracy:

< 10 cm

< 15 cm

< 30 cm

< 50 cm

< 1 m

< 2 m

< 5 m

< 10 m

< 20 m

Global

Sensor Type:

LiDAR

RADAR

Photogrammetry

Surface Type:

DSM

DEM

HDEM

CFM

CEM

Bathymetry

Mixed

Product Type:

Mass Points

Breaklines

TIN

GRID

Contours

Cross Sections

Other

Data Format:

ESRI GRID

LAS

ASCII (xyz)

IMAGE

Shapefile

ESRI TIN

Other

Classification:

State:

ACT

NSW

VIC

QLD

TAS

	Y Max

X Min		X Max

	Y Min

Basin

LGA

Term	Definition

Accuracy	The closeness of an estimated (for example, measured or computed) value to a standard or accepted [true] value of a particular quantity. Note: Because the true value is not known, but only estimated, the accuracy of the measured quantity is also unknown. Therefore, accuracy of coordinate information can only be estimated.
Absolute Accuracy	A measure that relates the stated elevation to the true elevation with respect to an established vertical datum. The computed value for the absolute vertical accuracy (tested, or compiled to) should be included in the metadata file.
Artefacts	Buildings, trees, towers, telephone poles or other elevated features that should be removed when depicting a DEM of the bare-earth terrain. Artefacts are not just limited to real features that need to be removed. They also include unintentional by-products of the production process, such as stripes in manually profiled DEMs. Any feature, whether man-made or system-made, that unintentionally exists in a digital elevation model.
AHD	The Australian Height Datum. Established in 1971 as a national datum for elevations based on observed mean sea level around the Australian coast line. Determined on the Australian mainland by an adjustment of a national levelling network constrained to mean sea level from continuous tidal observations over a period of 3 years at 30 tide gauges. AHD (Tasmania) was re-established in 1983 by adjusting the Tasmanian levelling network to mean sea level determined from one year of tidal observations at 2 tide gauges.
ALS	Airborne Laser Scanning (ALS). A terrain definition process which utilises an airborne laser source to accurately measure the earth surface from computation of laser range and return signal intensity, measurements recorded in-flight along with position and altitude data derived from airborne GPS and inertial subsystems. Falls into the category of airborne instrumentation known as LiDAR (Light Detection and Ranging). May also include Airborne Laser Bathymetry (ALB)
ASCII File	American Standard Code for Information Interchange (ASCII) file. A file whose data is in ASCII characters and does not include formatting such as bold, italic, centred text, etc.
Breakline	Linear features that describe a change in the smoothness or continuity of the surface.
Calibration	Procedures used to identify systematic errors in hardware, software, and procedures so that these errors can be corrected in preparing the data derived there from.
CEM	Canopy Elevation Model is a grid that represents the mean canopy height above the ground surface. The CEM is generally derived from the first return LiDAR data. The CEM therefore represents the highest derived vegetation surface.
Checkpoint	One of the points in the sample used to estimate the positional accuracy of the dataset against an independent source of higher accuracy.
Colour digital aerial photography (RGB)	Colour digital aerial photography (RGB) Digital photographic images captured by a digital sensor off an airborne platform such as a plane. Colour aerial photography includes red, green and blue wavelengths. To be acquired for the primary purpose of providing qualitative information of on-ground features, which will be used the development of the digital terrain model. However this could be used for other applications such as mapping broadly defined vegetation types.
Confidence Level	The probability that errors are within a range of given values. Contours A line connecting points of equal height, used to display a 3D surface on a 2D map or image
DEM	Digital Elevation Model: The representation of continuous elevation values over a topographic surface by a regular array of sampled z-values, referenced to a common datum. To be expressed as a grid or raster data set. The DEM is ground only representation and excludes vegetation such as trees and shrubs and human constructed features such as sheds and houses.
Digital Photography	Electronic image usually in a binary format that can be readily stored and edited on a computer. Aerial digital photography is digital photography taken from the vantage of an aircraft such as a helicopter or aeroplane.
DSM	Digital Surface Model : surface including ground, vegetation, building and structures defined by either random points or regular grid of spot heights and may include breaklines. Can be in point (ASCII), vector or raster format.
DTM	Digital Terrain Model: A topographic model of the earth's surface in digital format represented by mass points and may include breaklines. The DTM is a filtered version of a DSM that represents only bare earth surfaces. The DTM representation of ground includes works such as levees, banks and roads.
Elevation	Height above a specific vertical reference.
ESRI	Environmental Systems Research Institute (ESRI).
Ground control points	Ground control points Permanent survey control marks forming the local site datum, providing sites for GPS base-station control of aircraft trajectory and establishment of check points.
Ground sample distance (GSD)	Ground resolution of airborne or satellite imagery, e.g. 30cm GSD
ICSM	Inter-Governmental Committee on Surveying and Mapping
Hydrological enforcement	The removal of elevations from the tops of selected drainage structures (bridges and culverts) in a DEM, TIN or topographic dataset to depict the terrain under those structures. Also referred to as drainage enforced.
IFSAR	Interferometric Synthetic Aperture Radar: An airborne or spaceborne interferometer radar system, flown aboard rotary or fixed wing aircraft or space-based platforms, that is used to acquire 3-D coordinates of terrain and terrain features that are both man-made and naturally occurring. IFSAR systems form synthetic aperture images of terrain surfaces from two spatially separated antennae over an imaged swath that may be located to the left, right, or both sides of the imaging platform.
IHO	The International Hydrographic Organisation. The International Hydrographic Bureau is the publisher of the IHO Standards for Hydrographic Surveys (Special Publication 44, April 1998)
Image block file	Strip of digital imagery captured from a plane (or similar airborne platform) along a section of a flight run.
Image correlation	A computerised technique to match the similarities of pixels in one digital image with comparable pixels in its digital stereo image to automate or semi-automate photogrammetric compilation. Image correlation provides a faster method for generating DEMs photogrammetrically.
Independent source of higher accuracy	Data acquired independently of procedures to generate the dataset that is used to test the positional accuracy of a dataset. The independent source of higher accuracy shall be of the highest accuracy feasible and practicable to evaluate the accuracy of the dataset.
Interpolation	The estimation of z-values at a point with x/y coordinates, based on the known z-values of surrounding points.
LADS	Laser Airborne Depth Sounding, also referred to as Airborne LIDAR Bathymetry.
LAS	LAS version 1.1 is a standard LiDAR file format, defined by the American Society of Photogrammetry and Remote Sensing (ASPRS). LASV1.1 defines, amongst other things, mandatory data fields and point categories. This includes mandatory metadata documentation.
LiDAR	Light Detection and Ranging (LiDAR). A technology that determines distance to a surface using laser pulses. Distance is computed by measuring the time delay between transmission and detection of the reflected signal. Also referred to Airborne Laser Scanning (ALS).
Local Site Datum	Established network of state survey control marks in close proximity to each project area with published coordinates in a specific coordinate system.
Mass points	Irregularly spaced points, each with an x/y location and a z-value, used to form a TIN. When generated manually, mass points are ideally chosen to depict the most significant variations in the slope or aspect of TIN triangles. However, when generated by automated methods, For example, by LIDAR or IFSAR scanners, mass point spacing and pattern depend on characteristics of the technologies used to acquire the data. Mass points are most often used to make a TIN, but not always. They can be used as XYZ point data for interpolation of a grid without an intermediate TIN stage.
MHW	Mean High Water: A tidal level. The average of all high waters observed over a sufficiently long period.
National Digital Elevation Program (NDEP)	United States program established to promote the exchange of accurate digital land elevation data among government, private, and non-profit sectors and the academic community and to establish standards and guidance that benefit all users.
Near-Infrared digital aerial photography (NIR)	Digital near-infrared imagery captured by a digital sensor from an airborne platform such as a plane.
Order	The accuracy ranking of one measurement or survey with respect to other measurements or surveys.
Projective foliage cover (PFC)	The proportion of ground covered by foliage. PFC represents a measure of the openness of the vegetation canopy when projected vertically onto the ground. For LiDAR data PFC represents the proportion of returns from the vegetation canopy as a proportion of total returns.
Raw digital aerial photography	Digital aerial photography that has not been colour balanced, ortho-rectified or converted into a mosaic, and which still contains redundant imagery such as overlapping images.
RMSE	The square root of the mean of squared errors for a sample.
SP1	ICSM Special Publication No.1 - Standards and Practices for Control Surveys
SP44	International Hydrographic Organisation Standards for Hydrographic Surveys
TIN	A TIN is a set of adjacent, non-overlapping triangles computed from irregularly spaced points with x/y coordinates and z-values. The TIN data structure is based on irregularly spaced point, line, and polygon data interpreted as mass points and breaklines and stores the topological relationship between triangles and their adjacent neighbours. The TIN structure is often superior to other data models derived from mass points because it preserves the exact location of each ground point sample.

Searching the Portal

Searching the NEDF portal as an unregistered user allows for all data loaded within the portal to be discovered including associated metadata and web map services, however until the user is registered at a specific level, the order box is greyed out until the person registers themselves with NEDF.

The search button operates with the "And" operator between different criteria (eg Sensor Type and Product Type) and the "Or" operator between like search criteria (eg States).

The right hand side of the search tab contains optional fields that can be used to specify criteria when searching for datasets.
On the right hand side of the screen, various fields are available which can be used to specify criteria and restrict results when searching for datasets. The criteria work on a restriction model - if no criteria are provided, all results are returned. As soon as any criteria are submitted, only datasets matching the criteria are returned.

The available criteria are:

Vertical Accuracy: the accuracy of each point recorded in relation to its physical location on the earth.
Sensor Type: The equipment used to record the data.
Product Type:
Surface Type: The type of surface model.
Data Format: The format with which the data is distributed.
State: The Australian state where the dataset was recorded.

Upon selecting a state, the basin and LGA fields will be populated.

Basin predefined catchment basins supplied by GA.
LGA local government authority areas.

The search form also allows you to enter in the extents of latitude and longitude which the dataset must overlap. Note that this is the same as using the select tool on the map of Australia.Additionally, at the top of the form, you are able to search the metadata for all loaded datasets. You can search all metadata fields, or specific fields in the metadata:

Company Name

Flying Height
Acquisition Start Date
Acquisition End Date
Type
Average Point Spacing
Grid Resolution
Category
Projection

Base Data Layers

The layers tab enables you to specify which layers should be visible.

WMS (Web Map Services)

The NEDF Portal provides the capacity to add a WMS (Web Map Service) layers to the map of Australia to allow users to zoom to areas of interest and apply a more detailed spatial search. To achieve this, enter a WMS that is common to an area of interest.

The NEDF Portal also provides WMS (Web Map Service) layers of all base data held within the portal. This allows users to load data in proprietry GIS applications such as ArcGIS or MapInfo to analyse their elevation data needs against data extents provided in the WMS. Note: only base data is supplied in the WMS, not the elevation data sets.

Registering with the NEDF Portal

Registering with the NEDF portal is a simple operation, by just filling out the required details, and submitting to the NEDF administrator via the register button. It is a requirement to be registered prior to downloading data from the site.

The process of registering with the NEDF requires;

the user to provide their profile information,
the NEDF administrator to determine the level of authority to download restricted datasets (Note: some datasets are restricted for Government only use)
the NEDF administrator to grant access to the site at a defined level.

Please Note: Admistration of the NEDF portal is undertaken during working hours Monday - Friday 8am to 5pm.

Ordering

Ordering Data from the NEDF Portal

Once you have found the datasets you wish to download, you will need to complete the order process. This process will vary depending on your account status and the licence under which the dataset(s) has been released.

Datasets in the NEDF Portal come under three categories:

Creative Commons: These datasets are available freely, with the user being required to agree to the creative commons licence before the order will be processed.
NEDF Restricted Licence to Government Agencies: These datasets are released by GA, and are only available to registered government users.
Third Party Licence: These datasets are released by third party providers, and are available for registered government users which are required to agree to a licence governing terms of use before the datasets can be downloaded.

To create an order, check the box or boxes next to the specific datasets you wish to download. If your datasets are on multiple results pages, you can move through the pages and your selections will be remembered. Once you have selected the datasets, click order. This will take you to a page where you are able to configure your order.

You are able to set the following:

Mosaic: merges all the elevation data in the dataset that matches your criteria into a single data mosaic.
Resample: up-sampling the resolution of the image(s) in the dataset.
Resample Type: the interpolation method of how the data is re-sampled.

Enter the desired options, then click ‘perform order’ to submit the order.

The file size of the datasets will determine the mode of delivery of data to the user.
At current settings the portal will zip data to 400mb which will then available to the user at no cost, for data over 400mb the data will be downloaded to a holding area, where NEDF staff will copy data to a USB hard drive and ship to users at a nominal charge for hardware.

Current charges for USB drives are;

16GB @ $80 plus GST and Postage
1TB @ $250 plus GST and Postage

Depending on your account details and the licence the dataset is released under, you may be asked to accept a licence agreement.

When your order has been processed and prepared you will be sent a licence agreement which should be completed and returned to the specified address. When the agreement has been returned, the processing will recommence and you will be sent details about how to retrieve your completed order.

Updating User Profiles

Users of the NEDF Portal are able to update their information through the profile tab.
This includes the changing of passwords and there personal information.

WMS URL:
Layer Name:

List of displayed WMS links:

List of available WMS links:

Web Map Services (WMS):

All web map services available individually through REST API:

http://nedf.ga.gov.au:8399/arcgis/rest/services

From here data can be viewed in ArcGIS, GoogleEarth and Internet Explorer.