Tagged: LAND-Geodesy - Page 2

For further information about this dataset, see the Kaikoura earthquake information.

It is likely that many of these coordinates will be updated multiple times as marks move due to aftershocks and ongoing post-seismic deformation. It is therefore critical that the datum version and coordinate epoch date are recorded with any coordinates sourced from this dataset, along with the date the coordinates were accessed or downloaded.

These coordinates are computed from Continuously Operating Reference Station (CORS) data and geodetic surveys undertaken after the 14 November 2016 Kaikoura earthquake. They reflect earthquake movements up until the epoch date that is associated with each coordinate. Where possible, coordinates sourced from this dataset for use as control or calibration points in a project should be at the same or similar epochs. If not, post-seismic deformation may mean that new observations or coordinates do not fit well with these coordinates. Coordinates used as control or calibration points should also be well-distributed over the project area, so that any discrepancies resulting from the survey date being significantly different from the coordinate epoch date can be identified. If such discrepancies are identified, it may be necessary to use the LINZ PositioNZ-PP online processing service to generate control coordinates at the same (or nearly the same) epoch as the survey date.

Coordinates were calculated using SNAP v2.5.48. The origin of non-CORS coordinates is PositioNZ CORS that have been updated to include earthquake movements.

The 95% confidence interval uncertainties of coordinates are 0.02m horizontally and 0.03m vertically, relative to the PositioNZ network, at the epoch specified. In areas experiencing significant ongoing seismic activity, coordinates at the same mark at other epochs may differ by more than these uncertainties.

These coordinates are suitable for use in surveys and other geospatial positioning activities in the area impacted by the Kaikoura earthquake.

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.

For more information see here

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 polyline.

For more information see here

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 layer contains the DSM for LiDAR data from the Wellington region captured in 2013.
The DEM is available as layer Wellington LiDAR 1m DEM (2013).
The index tiles are available as layer Wellington LiDAR Index Tiles (2013).
The LAS point cloud is available from OpenTopography.

Lidar was captured for Greater Wellington Regional Council by Aerial Surveys in 2013. The datasets were generated by Landcare Research. The survey area includes Wellington, Porirua, Lower Hutt, Upper Hutt, Wairarapa, and Kapiti. Data management and distribution is by Land Information New Zealand.

Data comprises:
•DEM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•DSM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•Point cloud: las tiles in NZTM2000 projection, tiled into a 1km x 1km tile layout

Data was collected at >1 pulse/square metre pulse density. Attributes include:
-Elevation
-Intensity values
-Return number
-Adjusted GPS time
-Classification

Vertical datum is NZVD2016

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 layer contains the DEM for LiDAR data from the Kaikoura area captured in 2012.
The DSM is available as layer Canterbury - Kaikoura Lidar 1m DSM (2012).
The index tiles are available as layer Canterbury - Kaikoura Lidar Index Tiles (2012).
The LAS point cloud and vendor project reports are available from OpenTopography.

Lidar was captured for Environment Canterbury Regional Council by Aerial Surveys in 2012. Note that this capture was prior to the significant vertical and horizontal displacements from the 2016 Kaikoura earthquakes. The datasets were generated by Aerial Surveys and their subcontractors. The survey area includes the Kaikoura township area and adjacent coastal strips. Data management and distribution is by Land Information New Zealand.

Data comprises:
•DEM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•DSM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•Point cloud: las tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout

Data was collected at >1 pulse/square metre pulse density. Attributes include:
-Elevation
-Intensity values
-Return number
-Adjusted GPS time
-Classification

Vertical accuracy specification is +/-0.2m (@ 95% confidence)
Vertical datum is NZVD2016

This layer contains the DEM for LiDAR data from the Rangiora area captured in 2014.
The DSM is available as layer Canterbury - Rangiora LiDAR 1m DSM (2014).
The index tiles are available as layer Canterbury - Rangiora LiDAR Index Tiles (2014).
The LAS point cloud and vendor project reports are available from OpenTopography.

Lidar was captured for Waimakariri District Council and Environment Canterbury Regional Council by Aerial Surveys in March – June 2014. The datasets were generated by Aerial Surveys and their subcontractors. The survey area includes the Rangiora township area and the lower Ashley, Eyre, and Waimakariri river channels. Data management and distribution is by Land Information New Zealand.

Data comprises:
•DEM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•DSM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•Point cloud: las tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout

Planned pulse density is 1 pulse/square metre.

Vertical datum is NZVD2016.

This layer contains the index tiles for LiDAR data from the Wellington region captured in 2013.
The DEM is available as layer Wellington LiDAR 1m DEM (2013).
The DSM is available as layer Wellington LiDAR 1m DSM (2013).
The LAS point cloud is available from OpenTopography.

Lidar was captured for Greater Wellington Regional Council by Aerial Surveys in 2013. The datasets were generated by Landcare Research. The survey area includes Wellington, Porirua, Lower Hutt, Upper Hutt, Wairarapa, and Kapiti. Data management and distribution is by Land Information New Zealand.

Data comprises:
•DEM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•DSM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout
•Point cloud: las tiles in NZTM2000 projection, tiled into a 1km x 1km tile layout

Data was collected at >1 pulse/square metre pulse density. Attributes include:
-Elevation
-Intensity values
-Return number
-Adjusted GPS time
-Classification

Vertical datum is NZVD2016

Introduction
This dataset provides gravity observations, reductions and metadata for New Zealand’s national airborne gravity survey at flight elevation. A full description of each field in this dataset is available in the accompanying pdf NZ Airborne Gravity Flight Lines at Elevation (2013-2014) Description.

Description
New Zealand’s 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.

Gravity observations can be used to compute gravity anomalies: differences between measured gravity and an ellipsoidal model of the Earth’s gravity field. Gravity anomalies correspond to un-modelled density variations within the Earth’s crust and upper mantle. They are used to investigate concealed geological structures and for quasigeoid modelling.

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 raster layers created for each of the free-Air and Bouguer Anomalies which have been downward continued to ground surface NZ Airborne Gravity Free-Air Anomalies at Ground Surface (2013-2014) and NZ Airborne Gravity Bouguer Anomalies at Ground Surface (2013-2014).