The Lyttelton 1937 to NZVD2016 Conversion Raster provides users with a two arc-minute (approximately 3.6 kilometres) raster image of the conversion of normal-orthometric heights from the Lyttelton 1937 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](http://www.linz.govt.nz/regulatory/25009). The height conversion grid models the difference between the Lyttelton 1937 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy is better than 2 centimetres (95% Confidence interval). 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 STI77-NZGD2000 grid enables the conversion of normal-orthometric heights from the Stewart Island 1977 local vertical datum directly to New Zealand Geodetic Datum 2000 (NZGD2000) ellipsoidal heights. STI77-NZGD2000 is published on a one arc-minute grid (approximately 1.8 kilometres) extending over the benchmarks that nominally define the extent of the Stewart Island 1977 vertical datum (167.2° E to 168.8° E, 46.5° S to 47.5° S). The conversion value is represented by the attribute “delta”, in metres. This grid is a combination of New Zealand Quasigeoid 2016 [NZGeoid2016](https://data.linz.govt.nz/layer/3418) and the [STI77-NZVD2016](https://data.linz.govt.nz/layer/3442) height conversion grid. Where NZGeoid2016 is the reference surface for the New Zealand Vertical Datum 2016 (NZVD2016), while the STI77-NZVD2016 grid models the difference between the Stewart Island 1977 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. 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 BLF55-NZGD2000 grid enables the conversion of normal-orthometric heights from the Bluff 1955 local vertical datum directly to New Zealand Geodetic Datum 2000 (NZGD2000) ellipsoidal heights. BLF55-NZGD2000 is published on a one arc-minute grid (approximately 1.8 kilometres) extending over the benchmarks that nominally define the extent of the Bluff 1955 vertical datum (168.2° E to 168.9° E, 46.3° S to 46.8° S). The conversion value is represented by the attribute “delta”, in metres. This grid is a combination of New Zealand Quasigeoid 2016 [NZGeoid2016](https://data.linz.govt.nz/layer/3418) and the [BLF55-NZVD2016](https://data.linz.govt.nz/layer/3424) height conversion grid. Where NZGeoid2016 is the reference surface for the New Zealand Vertical Datum 2016 (NZVD2016), while the BLF55-NZVD2016 grid models the difference between the Bluff 1955 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. 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 Dunedin-Bluff 1960 to NZVD2016 Conversion Raster provides users with a two arc-minute (approximately 3.6 kilometres) raster image of the conversion of normal-orthometric heights from the Dunedin-Bluff 1960 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](http://www.linz.govt.nz/regulatory/25009). The height conversion grid models the difference between the Dunedin-Bluff 1960 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy is better than 2 centimetres (95% Confidence interval). 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 BLF55-NZVD2016 grid enables the conversion of normal-orthometric heights from the Bluff 1955 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](http://www.linz.govt.nz/regulatory/25009). BLF55-NZVD2016 is published on a two arc-minute grid (approximately 3.6 kilometres) extending over the benchmarks that nominally define the extent of the Bluff 1955 vertical datum (168.2° E to 168.9° E, 46.3° S to 46.8° S). The height conversion grid models the difference between the Bluff 1955 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy of BLF55-NZVD2016 is better than 3 centimetres (95% Confidence interval). 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 Dunedin 1958 to NZVD2016 Conversion Raster provides users with a two arc-minute (approximately 3.6 kilometres) raster image of the conversion of normal-orthometric heights from the Dunedin 1958 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](http://www.linz.govt.nz/regulatory/25009). The height conversion grid models the difference between the Dunedin 1958 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. From the GPS-levelling marks the expected accuracy is better than 2 centimetres (95% Confidence interval). 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 deformation model associated with the NZGD2000 datum was updated, nominally at 1 August 2013. The actual update of LINZ data took place on 14-15 December 2013. This update involved reverse patches, which means that the "reference coordinates" of features were updated. The main updates relate to the Christchurch earthquakes. The patch also updated coordinates affected by other South Island earthquakes since 2000. These updates have been incorporated into Landonline and resulted in spatial updates to all features in the affected areas. This data set contains contours indicating the extent and magnitude of the coordinate changes to assist in assessing the impact of this update on client data sets. This dataset is also available as a [multipolygon](http://data.linz.govt.nz/#/layer/1685-nzgd2000-deformation-model-version-2013-08-01-reverse-patch-coordinate-shifts-filled-contours/). For more information see [here](http://www.landonline.govt.nz/landonline-system-updates/south-island-coordinate-update)

The NPR62-NZGD2000 grid enables the conversion of normal-orthometric heights from the Napier 162 ocal vertical datum directly to New Zealand Geodetic Datum 2000 (NZGD2000) ellipsoidal heights. NPR62-NZGD2000 is published on a one arc-minute grid (approximately 1.8 kilometres) extending over the benchmarks that nominally define the extent of the Napier 1962 vertical datum (175.6° E to 177.9° E, 38.6° S to 40.6° S). The conversion value is represented by the attribute “delta”, in metres. This grid is a combination of New Zealand Quasigeoid 2016 [NZGeoid2016](https://data.linz.govt.nz/layer/3418) and the [NPR62-NZVD2016](https://data.linz.govt.nz/layer/3436) height conversion grid. Where NZGeoid2016 is the reference surface for the New Zealand Vertical Datum 2016 (NZVD2016), while the NPR62-NZVD2016 grid models the difference between the Napier 1962 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. 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 GSB26-NZGD2000 grid enables the conversion of normal-orthometric heights from the Gisborne 1926 local vertical datum directly to New Zealand Geodetic Datum 2000 (NZGD2000) ellipsoidal heights. GSB26-NZGD2000 is published on a one arc-minute grid (approximately 1.8 kilometres) extending over the benchmarks that nominally define the extent of the Gisborne 1926 vertical datum (177.0° E to 178.6° E, 37.4° S to 39.0° S). The conversion value is represented by the attribute “delta”, in metres. This grid is a combination of New Zealand Quasigeoid 2016 [NZGeoid2016](https://data.linz.govt.nz/layer/3418) and the [GSB26-NZVD2016](https://data.linz.govt.nz/layer/3430) height conversion grid. Where NZGeoid2016 is the reference surface for the New Zealand Vertical Datum 2016 (NZVD2016), while the GSB26-NZVD2016 grid models the difference between the Gisborne 1926 vertical datum and NZVD2016 using the LINZ GPS-levelling marks. 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).

Coordinates computed from surveys undertaken after the 14 February 2016 Canterbury earthquake. These should be consistent with any observations made after this earthquake (neglecting any localised deformation such as that due to liquefaction). **For further information about this dataset, see [the Canterbury earthquake information](http://www.linz.govt.nz/land/surveying/canterbury-earthquakes/geodetic-survey-control-network).** These coordinates are only provisional. Analysis is ongoing as further data is collected. Coordinates were calculated using SNAP v2.5.33. Stations were constrained using coordinates of distant PositioNZ continuous GNSS stations that were unaffected by the earthquake. The standard deviations of coordinates are 0.01m horizontally and 0.02m vertically, relative to the PositioNZ network. Coordinate changes due to the earthquake have been calculated by comparing pre and post-earthquake coordinates. Pre-earthquake coordinates were calculated relative to public and private continuous GNSS stations. These continuous GNSS stations had data processed for several days early in 2016 (before the earthquake). Other pre-earthquake geodetic data was then readjusted with the continuous GNSS data. Note that this means these coordinate changes may differ slightly from those that would be calculated by comparing the post-earthquake coordinates with those currently in the Geodetic Database. These coordinates are suitable for use in surveys and other geospatial activities in Canterbury and Christchurch.