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Gebco re-project to NZTM2000Quad cog file

GEBCO grid data are based on WGS84 which required to re-project into NZTM2000Quad tilematrix before importing into Basemaps. This instruction include the process of re-project Gebco data into NZTM2000Quad tiff file by using gdal commands. Then we can process the output by cogify commands to import into LINZ Basemaps.

Process

Download the lastest Gebco gridded bathymetry data.

Build VRT first with the Gdal command.

mkdir geotiff_output -p

docker run \
    --rm -it -v $PWD:$PWD \
    --workdir $PWD ghcr.io/osgeo/gdal:ubuntu-small-3.8.3 \
    gdalbuildvrt \
    geotiff_output/gebco_2023.vrt \
    gebco_2023_geotiff/*.tif

Wrap VRT and re-project into 2193 projection

docker run \
    --rm -it -v $PWD:$PWD \
    --workdir $PWD ghcr.io/osgeo/gdal:ubuntu-small-3.8.3 \
    gdalwarp \
    -of VRT \
    -r bilinear \
    -ot float32 \
    -multi \
    -s_srs EPSG:4326 \
    -t_srs EPSG:2193 \
    geotiff_output/gebco_2023.vrt \
    geotiff_output/wrapped_gebco_2023.vrt

GDAL translate to process the source file into NZTM2000 (EPSG:2193) COG within the NZTM2000Quad Extents

docker run \
    --rm -it -v $PWD:$PWD \
    --workdir $PWD ghcr.io/osgeo/gdal:ubuntu-small-3.8.3 \
    gdal_translate \
    -of COG \
    -co TARGET_SRS=EPSG:2193 \
    -co EXTENT=-3260586.7284,419435.9938,6758167.443,10438190.1652 \
    geotiff_output/wrapped_gebco_2023.vrt \
    geotiff_output/gebco_2023.tiff