The New Zealand Quasigeoid2009 (NZGeoid2009) can be used to convert GPS derived ellipsoidal heights to New Zealand Vertical Datum 2009 (NZVD2009) normal-orthometric heights that relate more closely to mean sea level and the local gravity field. NZGeoid2009 can also be used to transform heights to any of the 13 official local vertical datums used across New Zealand, more information on this transformation is available at http://www.linz.govt.nz/geodetic/conversion-coordinates/height-conversions. NZGeoid2009 is formally defined in the LINZ standard LINZS25004 which can be obtained from http://www.linz.govt.nz/geodetic/standards-publications/standards. NZGeoid2009 models the difference between the GRS80 ellipsoid and the geoid over the New Zealand region. The geoid is a theoretical surface of equal gravity that roughly approximates the mean level of the sea across the Earth. NZGeoid2009 is published by LINZ and was computed by enhancing the EGM2008 global gravity model with terrestrial gravity observations over New Zealand and DNSC08 satellite altimetry data over the oceans. The model is published on a one arc-minute grid covering New Zealand's extended exclusive economic zone. The accuracy of NZGeoid2009 is nominally ±0.08 metres across New Zealand. More information on the accuracy in relation to the 13 local vertical datums is provided in LINZS25004.

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. This dataset provides a 1 arc minute raster image of the Bouguer anomalies, which have been downward continued to the ground surface (McCubbine et al, 2017). 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 in other layers created for the free-air anomalies at ground surface and the along track observations from the gravity flight lines at flight elevation** [NZ Airborne Gravity Free-Air Anomalies at Ground Surface (2013-2014)](https://data.linz.govt.nz/layer/3532) 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 ZealandJournal of Geology and Geophysics.

This dataset provides information about the survey control network, position, position accuracy, mark name, mark type, condition and unique four letter code for geodetic marks in terms of New Zealand's official geodetic datum, New Zealand Geodetic Datum 2000 (NZGD2000). The dataset only contains marks that are within the New Zealand mainland and offshore islands. These positions have been generated using geodetic observations such as precise differential GPS or electronic distance and theodolite angle measurements. The positions are either 2D or 3D depending of the availability of this measurement data. The source data is from Land Information New Zealand's (LINZ) Landonline system where it is used by Land Surveyors. This dataset is updated daily to reflect changes made in the Landonline. The mark network is segmented into six control networks which provide control marks for specific purposes. The control_network field within this layer records this network with the 3 or 4 letter abbreviation code as follows: NRF - National Reference Frame NDMN - National Deformation Monitoring Network RDMN - Regional Deformation Monitoring Network LDMN - Local Deformation Monitoring Network CHN - Cadastral Horizontal Control Network CVN - Cadastral Vertical Control Network BGN - Basic Geospatial Network NHN - National Height Network Note a geodetic mark can be in more than network. Also not all geodetic marks are currently associated with a geodetic network. Those that are may be referred to as a control mark. For more information about the control networks refer to http://www.linz.govt.nz/geodetic/geodetic-programme/survey-control-networks/. Accuracy ============ Geodetic marks with a coordinate order of 5 or less have been positioned in terms of NZGD2000. Lower order marks (order 6 and greater) are derived from cadastral surveys, lower accuracy measurement techniques or inaccurate historical datum transformations, and may be significantly less accurate. The accuracy of NZGD2000 coordinates is described by a series of 'orders' classifications. Positions in terms of NZGD2000 are described by three-dimensional coordinates (latitude, longitude, ellipsoidal height). The accuracy of a survey mark is indicated by its order. Orders are classifications based on the quality of the coordinate in relation to the datum and in relation to other surrounding marks. For more information see http://www.linz.govt.nz/geodetic/datums-projections-heights/heights/coordinate-orders/ Note that the accuracy applies at the time the mark was last surveyed. Refer to the web geodetic database for historical information about mark coordinates. Note also that the existence of a mark in this dataset does not imply that there is currently a physical mark in the ground - the dataset includes destroyed or lost historical marks. The geodetic database provides more information on the mark status, valid at last time it was visited by LINZ or a maintenance contractor.

This dataset provides information about the position, height, height datum, height accuracy, mark name, mark type, condition and unique four letter identifier for geodetic marks that have an authoritative height in terms of a vertical datum. Heights are in datums defined at http://www.linz.govt.nz/geodetic/datums-projections-heights/vertical-datums/. All marks will have positions in terms of New Zealand’s official geodetic datum for Antarctica, Ross Sea Region Geodetic Datum 2000 (RSRGD2000). The horizontal positions of marks are provided for approximate location purposes only. This dataset only includes marks that are within the Antarctic region. The height data for these marks have been generated primarily using precise vertical angle and slope distance measurements from datum tide gauges. Some have been generated from levelling data. The source data is from Land Information New Zealand's (LINZ) Landonline system where it is used by Land Surveyors. This dataset is updated daily to reflect changes made in the Landonline. Accuracy ============ The accuracy of normal-orthometric heights are described by height orders. For more information see http://www.linz.govt.nz/geodetic/datums-projections-heights/heights/height-orders/. Note the accuracy applies at the time the mark was last surveyed - see the geodetic database for historical information about height coordinates.

The NZGD2000 Government CORS provides the locations of GNSS Continuously Operating Reference Stations operated by GNS Science under the GeoNet project (http://www.geonet.org.nz). Coordinates are from the LINZ Geodetic Database, in NZGD2000. These are split into several different networks: - PositioNZ - stations predominantly funded by LINZ, with some GeoNet funding. These provide a nationwide coverage of ~120km spacing. More info [here](http://apps.linz.govt.nz/positionz/) - GeoNet - stations funded by the GeoNet project. These are located in areas of geophysical interest, usually on the East Coast of the North Island. More info [here](http://www.geonet.org.nz) - SAGENZ - stations funded by the University of Otago, GNS Science, MIT, University of Colorado and UNAVCO. These Southern Alps Geodetic Experiment - New Zealand stations are generally semi-continuous sites. - Tide Gauge - stations co-located with tide gauges at major ports. Data is managed through the GeoNet project also. 30" RINEX data from all of these sites is available from the [GeoNet website](http://www.geonet.org.nz) Real Time data is available from all PositioNZ stations, and some GeoNet stations. For more information, see the [PositioNZ-RT website](http://apps.linz.govt.nz/positionz/rt/index.php)

This layer provides all marks and associated information that have an order of 6 or better. Cadastral surveys are required to connect to these marks if they are within a specified distance. A cadastral survey network mark is a node which is (or was) occupied by a physical survey monument that meets accuracy standards suitable for cadastral requirements. i.e. Cadastral Survey Network Marks have a NZGD2000 horizontal coordinate order of 6 or better. The complete definition for these mark orders is defined by the following Standard. "http://www.linz.govt.nz/survey-titles/cadastral-surveying/cadastral-standards/DocumentSummary.aspx?document=273" When a new cadastral survey network mark is named as part of a cadastral survey dataset (plan) its name consists of a mark type and number that is unique to that survey, followed by the plan number e.g. IS I DP 3456; IS II DP3456.

This dataset provides information about the position, height, height datum, height accuracy, mark name, mark type, condition and unique four letter identifier for geodetic marks that have an authoritative height in terms of a vertical datum. Heights are in datums defined at http://www.linz.govt.nz/geodetic/datums-projections-heights/vertical-datums/. All marks will have positions in terms a 3D New Zealand official geodetic datum. The horizontal positions of marks are provided for approximate location purposes only . This dataset only contains marks that are within the New Zealand mainland and offshore islands. The height data for these marks have been generated using precise levelling from datum tide gauges, or has been acquired by 3rd party sources either as levelling observations or direct heights. The source data is from Land Information New Zealand's (LINZ) Landonline system where it is used by Land Surveyors. This dataset is updated daily to reflect changes made in the Landonline. Accuracy ============ The accuracy of normal-orthometric heights are described by height orders. For more information see http://www.linz.govt.nz/geodetic/datums-projections-heights/heights/height-orders/. Note the accuracy applies at the time the mark was last surveyed - see the geodetic database for historical information about height coordinates.

This dataset provides information about the survey control network, position, position accuracy, mark name, mark type, condition and unique four letter code for geodetic marks in terms of New Zealand's official geodetic datum, New Zealand Geodetic Datum 2000 (NZGD2000). The dataset only contains marks that are within the New Zealand mainland and offshore islands. These positions have been generated using geodetic observations such as precise differential GPS or electronic distance and theodolite angle measurements. The positions are either 2D or 3D depending of the availability of this measurement data. The source data is from Land Information New Zealand's (LINZ) Landonline system where it is used by Land Surveyors. This dataset is updated daily to reflect changes made in the Landonline. The mark network is segmented into six control networks which provide control marks for specific purposes. The control_network field within this layer records this network with the 3 or 4 letter abbreviation code as follows: NRF - National Reference Frame NDMN - National Deformation Monitoring Network RDMN - Regional Deformation Monitoring Network LDMN - Local Deformation Monitoring Network CHN - Cadastral Horizontal Control Network CVN - Cadastral Vertical Control Network BGN - Basic Geospatial Network NHN - National Height Network Note a geodetic mark can be in more than network. Also not all geodetic marks are currently associated with a geodetic network. Those that are may be referred to as a control mark. For more information about the control networks refer to http://www.linz.govt.nz/geodetic/geodetic-programme/survey-control-networks/. Accuracy ============ Geodetic marks with a coordinate order of 5 or less have been positioned in terms of NZGD2000. Lower order marks (order 6 and greater) are derived from cadastral surveys, lower accuracy measurement techniques or inaccurate historical datum transformations, and may be significantly less accurate. The accuracy of NZGD2000 coordinates is described by a series of 'orders' classifications. Positions in terms of NZGD2000 are described by three-dimensional coordinates (latitude, longitude, ellipsoidal height). The accuracy of a survey mark is indicated by its order. Orders are classifications based on the quality of the coordinate in relation to the datum and in relation to other surrounding marks. For more information see http://www.linz.govt.nz/geodetic/datums-projections-heights/heights/coordinate-orders/ Note that the accuracy applies at the time the mark was last surveyed. Refer to the web geodetic database for historical information about mark coordinates. Note also that the existence of a mark in this dataset does not imply that there is currently a physical mark in the ground - the dataset includes destroyed or lost historical marks. The geodetic database provides more information on the mark status, valid at last time it was visited by LINZ or a maintenance contractor.

The New Zealand Quasigeoid2009 (NZGeoid2009) can be used to convert GPS derived ellipsoidal heights to New Zealand Vertical Datum 2009 (NZVD2009) normal-orthometric heights that relate more closely to mean sea level and the local gravity field. NZGeoid2009 can also be used to transform heights to any of the 13 official local vertical datums used across New Zealand, more information on this transformation is available at http://www.linz.govt.nz/geodetic/conversion-coordinates/height-conversions. NZGeoid2009 is formally defined in the LINZ standard LINZS25004 which can be obtained from http://www.linz.govt.nz/geodetic/standards-publications/standards. NZGeoid2009 models the difference between the GRS80 ellipsoid and the geoid over the New Zealand region. The geoid is a theoretical surface of equal gravity that roughly approximates the mean level of the sea across the Earth. NZGeoid2009 is published by LINZ and was computed by enhancing the EGM2008 global gravity model with terrestrial gravity observations over New Zealand and DNSC08 satellite altimetry data over the oceans. The model is published on a one arc-minute grid covering New Zealand's extended exclusive economic zone. The accuracy of NZGeoid2009 is nominally ±0.08 metres across New Zealand. More information on the accuracy in relation to the 13 local vertical datums is provided in LINZS25004.

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. This dataset provides a 1 arc minute raster image of the Bouguer anomalies, which have been downward continued to the ground surface (McCubbine et al, 2017). 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 in other layers created for the free-air anomalies at ground surface and the along track observations from the gravity flight lines at flight elevation** [NZ Airborne Gravity Free-Air Anomalies at Ground Surface (2013-2014)](https://data.linz.govt.nz/layer/3532) 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 ZealandJournal of Geology and Geophysics.