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  • Geoscience Australia carried out a marine survey on Carnarvon shelf (WA) in 2008 (SOL4769) to map seabed bathymetry and characterise benthic environments through colocated sampling of surface sediments and infauna, observation of benthic habitats using underwater towed video and stills photography, and measurement of ocean tides and wavegenerated currents. Data and samples were acquired using the Australian Institute of Marine Science (AIMS) Research Vessel Solander. Bathymetric mapping, sampling and video transects were completed in three survey areas that extended seaward from Ningaloo Reef to the shelf edge, including: Mandu Creek (80 sq km); Point Cloates (281 sq km), and; Gnaraloo (321 sq km). Additional bathymetric mapping (but no sampling or video) was completed between Mandu creek and Point Cloates, covering 277 sq km and north of Mandu Creek, covering 79 sq km. Two oceanographic moorings were deployed in the Point Cloates survey area. The survey also mapped and sampled an area to the northeast of the Muiron Islands covering 52 sq km. cloates_3m is an ArcINFO grid of Point Cloates of Carnarvon Shelf survey area produced from the processed EM3002 bathymetry data using the CARIS HIPS and SIPS software

  • 22-2/G51-13/4A-2 Vertical scale: 250

  • 45% coverage to east 1963 survey (E only) 22-1/E53-10/4 Vertical scale: 50

  • 1997 DEMtiles (a concatenation of 97DEM tiles) contains some samples of a representation of the Digital Elevation Model as TIFF and ECW images.

  • 50% coverage north 22-1/F53-15/3

  • Specification of a Global Nested Grid System for Use by Australia and New Zealand Matthew Purss1, Stuart Minchin1, Adam Lewis1, Simon Oliver1, Lesley Wyborn1, Robert Gibb2, Alex Fraser3, Ben Evans4 1 Geoscience Australia, Canberra, Australia, Matthew.Purss@ga.gov.au 2 Landcare Research, Palmerston North, New Zealand, gibbr@landcareresearch.co.nz 3 Victorian Partnership for Advanced Computing, Carlton, Vic, Australia, adfries@vpac.org 4 Australian National University - National Computational Infrastructure, Leonard Huxley Building, Canberra, ACT, Australia, Ben.Evans@anu.edu.au BACKGROUND Geoscientific data has already exceeded the peta-scale barrier. Converting this massive amount of data into timely information and decision support products is dependent on our capacity to rapidly analyse this data in a transparent and repeatable fashion. This can only be achieved through the conversion of traditional data archives into standardised data architectures that support parallel processing in high performance compute environments. In the near future, the challenge of high velocity, high volume (> a terabyte per day) will further increase the requirement for standard data structures that support the massively parallel processing required to convert high velocity data into near-real-time decision support information. One of the key elements of standardised data architecture is a common grid. A nested grid that supports global data models is required to ensure that the grid is capable of handling multiple input data streams rather than being sensor/data stream dependent. REVIEW OF THE ANZLIC NATIONAL NESTED GRID SPECIFICATION The Australian and New Zealand Land Information Council (ANZLIC) National Nested Grid (NNG) specification provides a framework for the interchange of spatial data between various grid resolutions. The Primary aim of the NNG is to define a practical guide for a data grid framework that enables and encourages sharing, reuse and integration of grid cell data, both within and across jurisdictions [1]. Unfortunately, deficiencies in the NNG specification limit its application for multi-domain and regional to global scaled 'big data' problems. In August 2013, Geoscience Australia hosted a workshop to review the NNG specification and identify ways to incorporate a Global Nested Grid (GNG) system into the specification that will improve its application and acceptance for use in solving the geoscientific problems of the future. This paper reports on the outcomes of this workshop. THE RHEALPIX GLOBAL NESTED GRID SYSTEM The revised Hierarchical Equal Area iso-Latitudinal Pixelation (rHEALPix) GNG system [3,4] has been recommended for application to Australia and New Zealand. It is an extension of the astronomically focused discrete global grid system developed by NASA (HEALPix - based on spherical symmetry) to study cosmic background microwave radiation. Figure 1 shows a graphical representation of the rHEALPix GNG system. Brisbane | Australia 20-25 Oct | 2013 7th eResearch Australasia Conference By extending HEALPix so that it can be applied to ellipsoids of revolution, such as WGS84, Gibb et. al. [4] have broadened the use of this GNG system to include terrestrial applications. Key features of rHEALPix include: (a) It is hierarchical, congruent, aligned for odd values of an integer parameter Nside (which defines the nesting of each cell at different resolutions), and has a constant aperture; (b) At every resolution its grid cells have equal areas; (c) At each resolution its grid cells align to parallels of latitude, which makes computing spherical harmonics fast; (d) Its planar projection has a low average angular and linear distortion; and, (e) It can be used for ellipsoids of revolution, such as WGS84. eResearch Australasia 2013 - Brisbane

  • 70% coverage, central area missing 22-1/H55-4/1 Contour interval: 10

  • F53/B1-152 Vertical scale: 50