NEDF Part 2: Implications for New Zealand

Australian NEDF implications for New Zealand

Essentially New Zealand and Australia face a similar set of issues. Elevation data was identified in the NZ Geospatial Strategy as one of the fundamental datasets that NZ needs and the Geospatial Office has a work programme initially around a review of LiDAR data in New Zealand. Australia is further ahead in assessment of its needs while New Zealand, primarily because of its size, starts with higher resolution national elevation datasets. However both countries broadly face the same set of issues in moving forward from the present suite of diverse marine and land based datasets and reference frames, a mixed history of digital and analogue source material and the same suite of modern technologies for acquiring new elevation data.

Where the countries differ significantly is in the pattern of national and local government agencies, the respective roles of potential research and industry partners, the interests of non-governmental organisations in the spatial sector and the government funding models that the respective governments are comfortable with. The differences in size, population and economies are also significant because they lift the opportunity for industry players to build a significant sustainable business model around spatial data acquisition, processing, services and added value. Despite the differences there is enormous potential for collaboration building on synergies between the two countries. Many New Zealand and Australian geospatial companies are significant players in both countries, there are strong ties between the research agencies in the two countries and also significant informal and formal dialogue between national and local government agencies.

Towards a NZ Elevation Data Framework

User Need Analysis

The NEDF User Need Analysis (ref 3), provides an excellent indication of the likely range of NZ users’ needs and issues. The top five Australian issues reported from participants at the series of workshop were: Standards, One-stop elevation data portal, Closing the data gap between land and sea, A common vertical datum for land and sea, Leadership – ie a strategy not just projects. If used as the starting point of a NZ study, it would short-circuit preparatory work and allow a study team to quickly identify types of users across all sectors and focus directly on differences between NZ and Australia.

Business Case

A number of government ministries have already established elevation data requirements (eg MfE, NZDF, DoC, TransitNZ & MCDEM) that are beyond what is readily available and MfE and many Regional and City Councils have invested significantly in LiDAR surveys – leading to the recent establishment of gLiDAR (Government LiDAR User Group). Since LINZ Topo50K dataset became readily available many industry players have created NZ DEMs of various resolutions (50m-15m) that are available in the market. There is no ‘free’ national elevation dataset and few of the commercial DEMs that are available have good documentation from a perspective of being an authoritative source of elevation data.

The NEDF Business Plan (ref 2) focuses on direct cost benefit to all layers of Government of a coordinated approach to elevation data, indirect benefit to the wider community of a free elevation dataset and the economic benefit of a vibrant business community providing location services augmented by elevation information.

The NZ experience confirming that this is likely to be true for NZ as well is probably best illustrated by the dramatic change in use of elevation data that followed the reduction in cost of the LINZ Topo50K elevation data in the mid 90s. Now – over ten years later – it is time for a next generation elevation data framework to trigger another explosion in use and wide availability of products such as Google Earth are whetting the public’s appetite for such services.

Science Case

At the time of the workshop, the NEDF Science Case (ref 5) was the weakest part of the NEDF justification. These weaknesses were considered to be readily addressed and this was expected to be done as part of the NEDF strategy review process following the workshop. New Zealand’s science system is relatively compact compared to Australia’s and so building a science case should be relatively easy. NIWA, GNS Science and Landcare Research have been the most significant participants historically but others in the science system have also generated and used elevation data for a wide range of studies such as: river flow, catchment delineation and processes, soil formation and description, automated satellite image interpretation, climate modelling, ecosystem modelling, biosecurity threat modelling, coastal processes, lahar modelling, wetland modelling.

Some current NZ elevation data activities

NZ Geospatial Office – is undertaking a LiDAR study with the expectation of producing an on-line metadata catalogue of NZ LiDAR datasets.

Local Government NZ – has formed gLiDAR a local government LiDAR users group (Ref 10).

Ministry for Environment – is purchasing extensive LiDAR for all of its Kyoto forest plots. This data will be available under a Whole of Government licence. (Ref 9)

Ministry for Civil Defence and Emergency Management – needs high quality coastal elevation (LiDAR) data for tsunami inundation threat study. (Ref 8 )

Dept of Conservation – has proposed the creation of KiwiDEM – a low resolution public, IP free, elevation dataset for use by the environmental sector. (Appendix 2)

Land Information NZ – has undertaking a detailed study to determine the feasibility of creating a unified land and bathymetric DEM with heights referenced to the GRS80 geoid used by NZGD2000. (Ref 7)

Land Information NZ – has developed a draft standard for a New Zealand Vertical Datum 2008, an equipotential surface equivalent to mean sea level, with reference to NZGD2000 / GRS80. (Ref 6)

KiwiImage Consortium – is using the 30m military SRTM DEM to ortho-rectify its QuickBird imagery, but the DEM itself isn’t available for use.

Landcare Research – has a PGSF research contract (SpInfo II) to produce an algorithm for deriving 5m or better DEM surfaces from ALOS PRISM stereo satellite imagery.

Landcare Research – has done a study concluding that the 30m SRTM elevation dataset consistently under-estimates high elevations. (Ref McNiell)

Landcare Research & Regional Councils – are negotiating to commence a study on the application, use and development of a managed on-line LiDAR workflow based on work in the US (GEON LiDAR Workflow) in New Zealand initially using Landcare Research’s new SCENZ-Grid cluster (104 cores, 400GB RAM, 20TB storage) and the 10Gb/s KAREN network.

Google – originally had very low quality elevation data (maybe 250m) for New Zealand in its Google Earth and Terrain shaded Google Maps products, but now has data of order 25m–30m. They don’t publish the specification or origin of their data, but this resolution is comparable to either the 30m SRTM dataset or DEM derived from the LINZ Topo50K data. The elevation data is an integral part of their products but isn’t explicitly available as elevation data for use other than as visualisation in their products.

Contents

NEDF Part 1: The Australian National Elevation Data Framework
NEDF Part 2: Implications for New Zealand
NEDF Part 3: Strawman NZ Elevation Data Framework
NEDF Part 4: Recommendations for a Plan of Action