This index enables users to identify the extent of the relationship grids provided on LDS, which are used to convert heights provided in terms of one of 13 historic local vertical datums to NZVD2016. The polygons comprising the index show the extent of the conversion grids. Users can view the following polygon attributes: Shape_VDR: Vertical Datum Relationship grid area LVD: Local Vertical Datum Control: Number of control marks used to compute the relationship grid Mean: Mean vertical datum relationship value at control points Std: Standard deviation of vertical datum relationship value at control points Min: Minimum vertical datum relationship value at control points Max: Maximum vertical datum relationship value at control points Range: Range of vertical datum relationship value at control points Ref: Reference control mark for the local vertical datum Ref_value: Vertical datum relationship value at the reference mark Grid: Formal grid id **Users should note that the values represented in this dataset have been calculated with the outliers excluded. These same outliers were excluded during the computation of the relationship grids, but were included when calculating the 95% confidence intervals** More information on converting heights between vertical datums can be found on the [LINZ website](http://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/converting-between-nzvd2016-nzgd2000-and-local-vertical-datums).

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](http://www.linz.govt.nz/regulatory/25009). 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](http://data.linz.govt.nz/layer/3419).** More information on these transformations is available [on the LINZ website](http://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/converting-between-nzvd2016-nzgd2000-and-local-vertical-datums).

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](http://www.linz.govt.nz/regulatory/25009). 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](http://data.linz.govt.nz/layer/3419).** More information on these transformations is available [on the LINZ website](http://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/converting-between-nzvd2016-nzgd2000-and-local-vertical-datums).

This index enables users to identify the extent of the relationship grids provided on LDS, which are used to convert heights provided in terms of one of 13 historic local vertical datums to NZVD2016. The polygons comprising the index show the extent of the conversion grids. Users can view the following polygon attributes: Shape_VDR: Vertical Datum Relationship grid area LVD: Local Vertical Datum Control: Number of control marks used to compute the relationship grid Mean: Mean vertical datum relationship value at control points Std: Standard deviation of vertical datum relationship value at control points Min: Minimum vertical datum relationship value at control points Max: Maximum vertical datum relationship value at control points Range: Range of vertical datum relationship value at control points Ref: Reference control mark for the local vertical datum Ref_value: Vertical datum relationship value at the reference mark Grid: Formal grid id **Users should note that the values represented in this dataset have been calculated with the outliers excluded. These same outliers were excluded during the computation of the relationship grids, but were included when calculating the 95% confidence intervals** More information on converting heights between vertical datums can be found on the [LINZ website](http://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/converting-between-nzvd2016-nzgd2000-and-local-vertical-datums).

New Zealand Quasigeoid 2016 Raster, provides users with a one arc-minute gridded (approximately 1.8 kilometres) raster image of the New Zealand Quasigeoid 2016 (NZGeoid2016). The relationship between the GRS80 ellipsoid and the New Zealand Vertical Datum 2016 (NZVD2016) is modelled by [NZGeoid2016] and is represented by the attribute “N”, in metres.(http://data.linz.govt.nz/layer/3418). NZVD2016 is formally defined in the LINZ standard [LINZS25009](http://www.linz.govt.nz/regulatory/25009). **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](http://data.linz.govt.nz/layer/3419).** More information on these transformations is available [on the LINZ website](http://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/converting-between-nzvd2016-nzgd2000-and-local-vertical-datums).

New Zealand Quasigeoid 2016 Raster, provides users with a one arc-minute gridded (approximately 1.8 kilometres) raster image of the New Zealand Quasigeoid 2016 (NZGeoid2016). The relationship between the GRS80 ellipsoid and the New Zealand Vertical Datum 2016 (NZVD2016) is modelled by [NZGeoid2016] and is represented by the attribute “N”, in metres.(http://data.linz.govt.nz/layer/3418). NZVD2016 is formally defined in the LINZ standard [LINZS25009](http://www.linz.govt.nz/regulatory/25009). **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](http://data.linz.govt.nz/layer/3419).** More information on these transformations is available [on the LINZ website](http://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/converting-between-nzvd2016-nzgd2000-and-local-vertical-datums).