vyperdatum

Vyperdatum

Vyperdatum [definition]

Installation

Vyperdatum requires GDAL which can be installed from the conda's conda-forge channel. Below, we first create a conda environment, install GDAL and Vperdatum.

conda create -n vd python=3.11
conda activate vd
conda install -c conda-forge proj=9.4 gdal=3.8.4 python-pdal
pip install vyperdatum

Before running vyperdatum, you need to download NOAA's datum files and the updated proj.db . Once downloaded, create a persistent environment variable VYPER_GRIDS to hold the path to directory where the downloaded grids and proj.db are located.

Usage

Vyperdatum offers a Transformer class to handle the transformation of point and raster data. The Transformer class applies transformation from crs_from to crs_to coordinate reference system. By default the transformation steps will be determined automatically:

from vyperdatum.transformer import Transformer

crs_from = "EPSG:6346"            # NAD83(2011) 17N
crs_to = "EPSG:6346+NOAA:98"      # NAD83(2011) 17N + MLLW
tf = Transformer(crs_from=crs_from,
                 crs_to=crs_to,
                 )

Alternatively, you may manually prescribe the transformation steps:

from vyperdatum.transformer import Transformer

crs_from = "EPSG:6346"            # NAD83(2011) 17N
crs_to = "EPSG:6346+NOAA:98"      # NAD83(2011) 17N + MLLW
steps = [{"crs_from": "EPSG:6346", "crs_to": "EPSG:6318", "v_shift": False},
         {"crs_from": "EPSG:6319", "crs_to": "EPSG:6318+NOAA:98", "v_shift": True},
         {"crs_from": "EPSG:6318", "crs_to": "EPSG:6346", "v_shift": False}
         ]
tf = Transformer(crs_from=crs_from,
                 crs_to=crs_to,
                 steps=steps
                 )

Once an instance of the Transformer class is created, the transform() method can be called. Vyperdatum supports all GDAL-supported drivers, variable resolution BAG, LAZ and NPZ point-cloud files.

transform

tf.transform(input_file=<PATH_TO_INPUT_RASTER_FILE>,
             output_file=<PATH_TO_OUTPUT_RASTER_FILE>
             )

You may also, directly call the file-specific transform methods instead of the generic Transformer.transform() method:

Click to see pseudo-code examples

# dircet point transformation. x, y, z can be arrays, too.
x, y, z = 278881.198, 2719890.433, 0
xt, yt, zt = tf.transform_points(x, y, z, always_xy=True, allow_ballpark=False)

# GDAL-supported raster transform  
tf.transform_raster(input_file=<PATH_TO_INPUT_RASTER_FILE>,
                    output_file=<PATH_TO_OUTPUT_RASTER_FILE>
                    )

# VRBAG transform
tf.transform_vrbag(input_file=<PATH_TO_INPUT_VRBAG_FILE>,
                   output_file=<PATH_TO_OUTPUT_VRBAG_FILE>
                   )

# LAZ transform
tf.transform_laz(input_file=<PATH_TO_INPUT_LAZ_FILE>,
                 output_file=<PATH_TO_OUTPUT_LAZ_FILE>
                 )

# NPZ transform
tf.transform_npz(input_file=<PATH_TO_INPUT_NPZ_FILE>,
                 output_file=<PATH_TO_OUTPUT_NPZ_FILE>
                 )

Documentation

For a quick start, more detailed descriptions or search through the API, see Vyperdatums's documentation at: https://vyperdatum.readthedocs.io.