Tagged: land geodesy - Page 2

This layer contains the DSM for LiDAR data from the Christchurch and Selwyn areas captured in 2015.
The DEM is available as layer Canterbury - Christchurch and Selwyn LiDAR 1m DEM (2015).
The index tiles are available as layer Canterbury - Christchurch and Selwyn LiDAR Index Tiles (2015).
The LAS point cloud and vendor project reports are available from OpenTopography.

Lidar was captured for Environment Canterbury Regional Council by AAM between 5 October and 7 November 2015. The datasets were generated by AAM and their subcontractors. The survey area includes Christchurch City and parts of the Selwyn district. 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 4 pulses/square metre.

Vertical accuracy specification is +/- 0.20m (95%).

Horizontal accuracy specification is +/- 1.00m (95%).

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 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

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 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 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.

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

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.

This layer contains the index tiles for LiDAR data from the Christchurch and Selwyn areas captured in 2015.
The DEM is available as layer Canterbury - Christchurch and Selwyn LiDAR 1m DEM (2015).
The DSM is available as layer Canterbury - Christchurch and Selwyn LiDAR 1m DSM (2015).
The LAS point cloud and vendor project reports are available from OpenTopography.

Lidar was captured for Environment Canterbury Regional Council by AAM between 5 October and 7 November 2015. The datasets were generated by AAM and their subcontractors. The survey area includes Christchurch City and parts of the Selwyn district. 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 4 pulses/square metre.

Vertical accuracy specification is +/- 0.20m (95%).

Horizontal accuracy specification is +/- 1.00m (95%).

Vertical datum is NZVD2016.

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.

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.