ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata
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4167
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Title
NZ Airborne Gravity Free-Air Anomalies at Ground Surface (2013-2014)
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Abstract
**Introduction** This dataset provides a 1 arc minute raster image of the free-air gravity anomalies, which have been downward continued to the ground surface (McCubbine et al, 2017).
**Description** Gravity anomalies are differences between measured gravity (from the airborne gravity dataset) and an ellipsoidal model of the Earth’s gravity field (GRS80). Gravity anomalies correspond to un-modelled density variations within the Earth’s crust and upper mantle. They are used to investigate concealed geological structures and for quasigeoid modelling.
These free-air anomalies show values which include gravitation impact of the topography.
The national airborne gravity dataset is comprised of more than 50,000 linear km of flight observations, covering the three main islands of New Zealand and up to 10km offshore.
As the airborne gravity dataset was measured at flight altitude, the observations have been reduced to the ground surface (a process known as downward continuation).
The national airborne gravity dataset was collected as a joint project between Land Information New Zealand (LINZ), GNS Science (GNS) and Victoria University of Wellington (VUW). The airborne survey was completed in a total of eight months, over two campaigns: August – October 2013, and February – June 2014.
**Users may also be interested other layers created for Bouguer anomalies at ground surface and the along track observations from the gravity flight lines at flight elevation** [NZ Airborne Gravity Bouguer Anomalies at Ground Surface (2013-2014)](https://data.linz.govt.nz/layer/3530) and [NZ Airborne Gravity Flight Lines at Elevation (2013-2014)](https://data.linz.govt.nz/layer/3531).
McCubbine, J. Stagpoole, V. Caratori-Tontini, F. Amos, M. Smith, E. and Winefield, R. (2017). Gravity anomaly grids for the New Zealand region. Manuscript submitted for publication New Zealand Journal of Geology and Geophysics.
Purpose
Purpose of this dataset is to supply the national airborne gravity dataset for use in geophysical research and mapping.
Land Information New Zealand and the New Zealand Government.
All rights reserved
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copyright
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Released under Creative Commons Attribution 4.0 International with:
Following Attribution: If you publish, distribute or otherwise disseminate this work to the public without adapting it, the following attribution to Land Information New Zealand should be used.'CC BY 4.0 Land Information New Zealand'
If you adapt this work in any way or include it in a collection, and publish, distribute or otherwise disseminate that adaptation or collection to the public, the following attribution to Land Information New Zealand should be used.'Contains data sourced from the LINZ Data Service and licensed for reuse under CC BY 4.0.'
If 'attribution stacking' problems exist then the requirement to display the above attribution statements is waived and in lieu the attribution statement is to be made in any terms or conditions associated with the work/product/application/ etc.
This dataset is comprised of the downward continued free-air anomalies from the national airborne gravity survey. The downward continued process was completed using least squares collocation, a process which grids the dataset while reducing the data observed at elevation to the ground surface.
The airborne survey was observed over a period of eight months, over two campaigns: August – October 2013, and February – June 2014.
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unclassified
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Copyright 2016 Crown copyright (c)
Land Information New Zealand and the New Zealand Government.
All rights reserved
Use Constraints
Restriction Code
copyright
Metadata Constraints
Legal Constraints
Use Limitation
Released under Creative Commons Attribution 4.0 International
