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).
**NZ height conversion index v20160627**
More information regarding the vertical datum relationship grids, can be found on the [LINZ website](http://www.linz.govt.nz/data/geodetic-system/datums-projections-and-heights/vertical-datums/vertical-datum-relationship-grids).