FAD227C240E247A8E040CD9B214430D3EnglishManager Geophysics and Remote SensingDepartment of Mining and EnergyManager Geophysics and Remote Sensing(08) 8999 6443(08) 8999 6824geoscience.info@nt.gov.au2020-11-23AS/NZS ISO 19115 Geographic Information - Metadata, ANZLIC Metadata Profile1.0 Gravity Grids of the Northern Territory2007-03-01Gravity grids of the Northern Territory consist of spherical cap Bouguer anomaly gravity and derived grids interpolated from a compilation of 218,155 ground gravity stations acquired by the Northern Territory Government, Commonwealth Government, and Industry since the 1950's. More than 75% of the Territory is covered by gravity stations at a spacing of 4km or better, with historical 11km spaced stations covering the remaining area. The Bouguer anomaly grids have been calculated using the AAGD07 formulae with a density value of 2670 kg/m3 and are presented in um/s2. The input dataset, including longitude, latitude and spherical cap Bouguer anomaly, are provided as a comma separated text file as well as GIS files in MapInfo and ESRI format. Copyright Northern Territory of Australia (Northern Territory Geological Survey) 2018 With the exception of the Northern Territory of Australia logo, other government and corporate logos and where otherwise noted, all material in this publication is provided under a Creative Commons Attribution 4.0 International licence (https://creativecommons.org/licenses/by/4.0/legalcode). You are free to re-use the work under the licence, on the condition that you attribute the Northern Territory of Australia (Northern Territory Geological Survey) and comply with the other licence terms. Disclaimer: While all care has been taken to ensure that information contained in this publication is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of its information. The Northern Territory of Australia gives no warranty or assurance, and makes no representation as to the accuracy of any information or advice contained in this publication, or that it is suitable for your intended use. You should not rely upon information in this publication for the purpose of making any serious business or investment decisions without obtaining independent and/or professional advice in relation to your particular situation. The Northern Territory of Australia disclaims any liability or responsibility or duty of care towards any person for loss or damage caused by any use of, or reliance on the information contained in this publication.English-26-111291381964-01-202020-08-14datasetnot knownComplete0not knownNot applicable0not knownAccuracy of the height measurements can vary from centimetres to over 10m while spatial accuracy may vary from centimetres up to approximately 250m in the oldest data. Older data is being progressively replaced. Spatial and height accuracy are generally in the centimetre range for modern (post 1990) surveys. 0not knownNot applicable 0The Generic Mapping Tools gridding algorithm was used to create the base gravity grid. Derived products were created using intrepid Geophysics two dimensional Fourier filtering. Five Grids are provided as follows: 1. The spherical cap Bouguer anomaly grid: NT_Gravity_2020_BA_GDA94DD_GRD.ers 2. The first vertical derivative of the spherical cap Bouguer anomaly grid: NT_Gravity_2020_BA_1VD_GDA94DD_GRD.ers 3. The spherical cap Bouguer anomaly grid with a first order polynomial trend removed: NT_Gravity_2020_BA_residual_GDA95DD_GRD.ers 4. The residual spherical cap Bouguer anomaly grid upward continued 250m: NT_Gravity_2020_BA_residual_UC250m_GDA94DD_GRD.ers 5. The first vertical derivative of the upward continued spherical cap Bouguer anomaly grid: NT_Gravity_2020_BA_UC250cm_1VD_GDA94DD_GRD.ers The input datasets are provided with longitude, latitude and spherical cap Bouguer anomaly values as follows: 1. Comma separated text files: NT_Gravity_2020_Pts_GDA94DD_CSV.csv 2. MapInfo format files: NT_Gravity_2020_PTS_GDA94DD_TAB.DAT NT_Gravity_2020_PTS_GDA94DD_TAB.ID NT_Gravity_2020_PTS_GDA94DD_TAB.MAP NT_Gravity_2020_PTS_GDA94DD_TAB.TAB 3. ESRI shape format files: NT_Gravity_2020_PTS_GDA94DD_TAB.dbf NT_Gravity_2020_PTS_GDA94DD_TAB.prj NT_Gravity_2020_PTS_GDA94DD_TAB.shp NT_Gravity_2020_PTS_GDA94DD_TAB.shx