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Diffstat (limited to 'nz_linz/nz_linz_README.txt')
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diff --git a/nz_linz/nz_linz_README.txt b/nz_linz/nz_linz_README.txt index d55943a..13928e7 100644 --- a/nz_linz/nz_linz_README.txt +++ b/nz_linz/nz_linz_README.txt @@ -15,6 +15,23 @@ The New Zealand grids are published under the ## Included grids +### NZGD2000 to ITRF96 transformation + +*Filename*: nz_linz_nzgd2000-(version).json +*Reference*: https://www.linz.govt.nz/data/geodetic-system/datums-projections-and-heights/geodetic-datums/new-zealand-geodetic-datum-2000-nzgd2000/nzgd2000-deformation-model + +This is a set of deformation model files for each of the versions of the NZGD2000 datum. +Each version is identified by a nominal publication date in yyyymmdd date format (for example nz_linz_nzgd2000-20180701.json. +The JSON files define the deformation model using a set of GeoTiff files, each of which is names with the prefix nz_linz_nzgd2000. +Note that the transformation from ITRF96 to other realisations such as ITRF2008 should use the NZ specific transformations, for example EPSG:9082 to transform +between between ITRF2008 and ITRF96. These are documented in +https://www.linz.govt.nz/file/itrftonzgd2000pdf. + +Example of conversion from NZGD2000 to ITRF96 at epoch 2016.5 + + echo '173 -41 0 2016.5' | \ + cct -t 2016.5 -d 8 +proj=defmodel +model=nz_linz_nzgd2000-20180701.json + ### NZGD1949 to NZGD2000 transformation *Filename*: nz_linz_nzgd2kgrid0005.tif |