Oceania Geodetic Data

This layer identifies critical survey marks which Toitū Te Whenua (Land Information New Zealand) requires to be physically protected.

Thousands of vital survey marks exist in New Zealand. This layer identifies critical survey marks that should not be disturbed or destroyed.
Like utilities such as cables and pipes, survey marks are valuable assets, predominately in the road reserve, with many survey marks set below or at ground level and therefore not highly visible or apparent. They often remain unnoticed until roads or footpaths have been excavated and the survey marks disturbed or destroyed.
Publication of the NZ Protected Survey Marks dataset enables the potential for disturbance or destruction of these valuable survey marks to be assessed, and if needed, the marks protected prior to the commencement of any excavation work.

People involved in construction, from design to the works itself, are responsible for ensuring that survey marks are not disturbed or destroyed. When works have the potential to disturb or destroy existing cadastral and geodetic marks, Toitū Te Whenua needs to be notified so that it can assess whether the marks should be reinstated or replaced. Find out more about looking after the national survey network, and how to contact the Toitū Te Whenua Survey Protection Advisory Service.

Please note there may be other important survey marks not identified on this layer, and that Toitū Te Whenua recommends consultation with a Licensed Cadastral surveyor before any construction or earthworks begin.

If you notice a damaged survey mark, you can report it to Toitū Te Whenua by filling out a form on this website, or by sending feedback via the Geomarks App.

This dataset provides information about the position, position accuracy, mark name, mark type, condition and unique four letter code for geodetic marks in terms of a New Zealand's official geodetic datum.

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 angles measurements. The positions are either 2D or 3D depending of the availability of this measurement data.

The source data is from Toitū Te Whenua 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

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

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 NZGD2000 Meridional Circuit Boundaries as defined by LINZ. The Rules for Cadastral Survey require surveyors to carry out surveys in terms of one of 28 Transverse Mercator meridional circuits.

The cos_id contained within this data is a reference to the Landonline coordinate system identifier For more information see crs_coordinate_system in the Landonline BDE data dictionary documentation. These polygons were digitised from an NZMS 266 map.

Original data sourced from here

The MOT53-NZVD2016 grid enables the conversion of normal-orthometric heights from the Moturiki 1953 local vertical datum to the New Zealand Vertical Datum 2016 (NZVD2016).

The conversion value is represented by the attribute “O”, in metres.

This conversion and NZVD2016 are formally defined in the LINZ standard LINZS25009.

MOT53-NZVD2016 is published on a two arc-minute grid (approximately 3.6 kilometres) extending over the benchmarks that nominally define the extent of the Moturiki 1953 vertical datum (174.5° E to 178.26° E, 36.5° S to 40.7° S).

The height conversion grid models the difference between the Moturiki 1953 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy of MOT53-NZVD2016 is better than 2 centimetres (95% Confidence interval).

More information on converting heights between vertical datums can be found on the LINZ website.

The AUK46-NZVD2016 grid enables the conversion of normal-orthometric heights from the Auckland 1946 local vertical datum to the New Zealand Vertical Datum 2016 (NZVD2016).

The conversion value is represented by the attribute “O”, in metres.

This conversion and NZVD2016 are formally defined in the LINZ standard LINZS25009.

AUK46-NZVD2016 is published on a two arc-minute grid (approximately 3.6 kilometres) extending over the benchmarks that nominally define the extent of the Auckland 1946 vertical datum (174.0° E to 176.2° E, 36.1° S to 38.0° S).

The height conversion grid models the difference between the Auckland 1946 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy of AUK46-NZVD2016 is better than 2 centimetres (95% Confidence interval).

More information on converting heights between vertical datums can be found on the LINZ website.

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 www.linz.govt.nz/guidance/geodetic-system/coordina... .

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 Toitū Te Whenua 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 www.linz.govt.nz/guidance/geodetic-system/coordina... .

Note the accuracy applies at the time the mark was last surveyed - see the geodetic database for historical information about height coordinates.

The OTP64-NZVD2016 grid enables the conversion of normal-orthometric heights from the One Tree Point 1964 local vertical datum to the New Zealand Vertical Datum 2016 (NZVD2016).

The conversion value is represented by the attribute “O”, in metres.

This conversion and NZVD2016 are formally defined in the LINZ standard LINZS25009.

OTP64-NZVD2016 is published on a two arc-minute grid (approximately 3.6 kilometres) extending over the benchmarks that nominally define the extent of the One Tree Point 1964 vertical datum (171.3° E to 174.4° E, 40.4° S to 42.7° S).

The height conversion grid models the difference between the One Tree Point 1964 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy of OTP64-NZVD2016 is better than 1 centimetre (95% Confidence interval).

More information on converting heights between vertical datums can be found on the LINZ website.

The relationship between the GRS80 ellipsoid and the New Zealand Vertical Datum 2016 (NZVD2016) is modelled by the New Zealand Quasigeoid 2016 (NZGeoid2016). The relationship value is represented by the attribute “N”, in metres.

This relationship and NZVD2016 is formally defined in the LINZ standard LINZS25009.

NZGeoid2016 can be used to convert New Zealand Geodetic Datum 2000 (NZGD2000) ellipsoidal heights to NZVD2016 normal-orthometric heights.

The conversion value is represented by the attribute “N”, in metres.

NZGeoid2016 is published on a one arc-minute grid (approximately 1.8 kilometres) over the New Zealand continental shelf (160° E to 170° W, 25° S to 60° S).

NZGeoid2016 was calculated by enhancing the EIGEN-6C4 global gravity model with, terrestrial, ship-track, satellite and airborne gravity data. GPS-levelling observations were not used to compute NZGeoid2016.

Users may also be interested in transforming heights to any of the 13 historic local vertical datums used in New Zealand using the appropriate datum relationship grid displayed in the NZ Height Conversion Index.

More information on these transformations is available on the LINZ website.

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 www.linz.govt.nz/geodetic/geodetic-programme/surve....

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 www.linz.govt.nz/geodetic/datums-projections-heigh...

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 Canterbury region of New Zealand experienced a sequence of significant earthquakes during 2010 and 2011. These earthquakes occurred on 2010-09-04, 2011-02-22, 2011-06-13 and 2011-12-23. This layer contains coordinates computed from GNSS fast static and network RTK surveys undertaken after the Canterbury earthquakes. It also includes Lyttelton Vertical Datum 1937 and Christchurch Drainage Datum heights, derived from the GNSS data.

Users may also be interested in the simplified data in the companion layer Canterbury Earthquake Geodetic Marks (2010, 2011) - Simple.

These coordinates are only provisional. Analysis is ongoing as further data is collected. Coordinates were calculated using SNAP v2.3.61. Stations were constrained using coordinates calculated by GNS Science. Some coordinates were calculated from data provided by Christchurch City Council and other public and private organisations. No precise levelling data has been used.

The uncertainty (one standard deviation) is 0.02m horizontally, and 0.03m vertically for NZGD2000 ellipsoidal heights. The uncertainty (one standard deviation) of the Lyttelton Vertical Datum 1937 and Christchurch Drainage Datum heights is 0.05m.

The coordinates calculated prior to 2010-09-04 have been calculated from a combined adjustment including LINZ data and additional data provided by public and private organisations. These coordinates differ from those in the Geodetic Database and more accurately reflect the position of the mark immediately prior to the 2010-09-04 earthquake.

The deformation model igns2011_working.grd calculated from a model (v4) provided by GNS Science on 28 April 2011 was used to remove secular deformation.

Lyttelton Vertical Datum 1937 heights have been computed from NZGD2000 ellipsoidal heights by subtracting NZGeoid2009 geoid heights and adding an offset of 0.47m to bring in terms of Lyttelton Vertical Datum 1937. Christchurch Drainage Datum (CDD) heights have been computed in the Christchurch area from NZGD2000 ellipsoidal heights by subtracting NZGeoid2009 geoid heights and adding an offset of 0.523m (specifically calculated for Christchurch City) to bring in terms of Lyttelton Vertical Datum 1937 (for Christchurch) and a further offset of 9.04m to bring in terms of CDD.

The model used to estimate whether movements greater than 2cm occurred at a mark (excluding those due to liquefaction or other localised deformation) after the 2010-09-04 earthquake was provided by GNS Science (Darfield_Sep2010_model_8.5_grid_displacements_calcs.xls). The model used to estimate whether movements greater than 2cm occurred at a mark (excluding those due to liquefaction or other localised deformation) after the 2011-02-22 earthquake was provided by GNS Science (Chch_Feb2011_geodetic_source_model_3.21.xls). The model used to estimate whether movements greater than 2cm occurred at a mark (excluding those due to liquefaction or other localised deformation) after the 2011-06-13 earthquake was provided by GNS Science (Chch_Jun2011_geodetic_source_model_0.4.xls). The model used to estimate whether movements greater than 2cm occurred at a mark (excluding those due to liquefaction or other localised deformation) after the 2011-12-23 earthquake was provided by GNS Science (Chch_Dec2011_geodetic_source_model_0.2.xls).

These coordinates are suitable for use in surveys and other geospatial activities in Canterbury and Christchurch.

For full information about this dataset, see the Canterbury earthquake information on the LINZ website.