Python module that drives PROJ to use VDatum grids in a simple and clear way. Requires that VDatum be installed already (you can find VDatum here. Developed in Python3.
VDatum is "a free software tool being developed jointly by NOAA's National Geodetic Survey (NGS), Office of Coast Survey (OCS), and Center for Operational Oceanographic Products and Services (CO-OPS)...to vertically transform geospatial data among a variety of tidal, orthometric and ellipsoidal vertical datums".
Vyperdatum allows for VDatum to be used in production bathymetric processing software in a clean and precise way. In addition, Vyperdatum builds a custom Compound and Vertical CRS object that well documents the resulting transformation, so that the inverse transformation can be accurately applied later to get back to the pivot datum (NAD83(2011)/EPSG:6319.
Vyperdatum is not on PyPi, but can be installed using pip.
(For Windows Users) Download and install Visual Studio Build Tools 2019 (If you have not already): MSVC Build Tools
Download and install conda (If you have not already): conda installation
Download and install git (If you have not already): git installation
Some dependencies need to be installed from the conda-forge channel. I have an example below of how to build this environment using conda.
Perform these in order:
conda create -n vyper python=3.8.8
conda activate vyper
conda install -c conda-forge gdal=3.2.1
pip install git+https://github.com/noaa-ocs-hydrography/vyperdatum.git#egg=vyperdatum
Vyperdatum offers to main classes:
- VyperPoints - for transforming 2d/3d point datasets
- VyperRaster - for transforming GDAL supported raster datasets
For either of these objects, the first run needs to set the path to the VDatum installation in order for Vyperdatum to initialize properly:
from vyperdatum.points import VyperPoints
vp = VyperPoints(vdatum_directory='path/to/vdatum')
From there it is simple to start performing transformations. Use the following examples to get started:
-- we assume vdatum_directory has already been set in these examples --
-
Basic vertical transformation from NAD83 height to MLLW
vp = VyperPoints() x = np.array([-76.19698, -76.194, -76.198]) y = np.array([37.1299, 37.1399, 37.1499]) z = np.array([10.5, 11.0, 11.5]) # source ('nad83') = nad83(2011)/nad83(2011)height # destination ('mllw') = nad83/mllw vp.transform_points(6319, 'mllw', x, y, z=z) # this is a shortcut for vp.transform_points((6319, 'ellipse'), 'mllw', x, y, z=z) vp.x Out: array([-76.19698, -76.194 , -76.198 ]) vp.y Out: array([37.1299, 37.1399, 37.1499]) vp.z Out: array([47.735, 48.219, 48.685]) vp.unc Out: array([0.115, 0.115, 0.115]) print(vp.out_crs.to_wkt()) COMPOUNDCRS["NAD83(2011) + mllw", GEOGCRS["NAD83(2011)", DATUM["NAD83 (National Spatial Reference System 2011)", ELLIPSOID["GRS 1980",6378137,298.257222101,LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]], CS[ellipsoidal,2], AXIS["geodetic latitude (Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]], AXIS["geodetic longitude (Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]], USAGE[SCOPE["Horizontal component of 3D system."], AREA["Puerto Rico - onshore and offshore. United States (USA) onshore and offshore - Alabama; Alaska; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; Florida; Georgia; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming. US Virgin Islands - onshore and offshore."], BBOX[14.92,167.65,74.71,-63.88]],ID["EPSG",6318]], VERTCRS["mllw", VDATUM["mllw"], CS[vertical,1], AXIS["gravity-related height (H)",up,LENGTHUNIT["metre",1,ID["EPSG",9001]]], REMARK["vdatum=vdatum_4.1.2_20201203,vyperdatum=0.1.6,base_datum=[NAD83(2011)], regions=[MDVAchb12_8301], pipelines=[+proj=pipeline +step +proj=vgridshift grids=core\\geoid12b\\g2012bu0.gtx +step +inv +proj=vgridshift grids=MDVAchb12_8301\\tss.gtx +step +proj=vgridshift grids=MDVAchb12_8301\\mllw.gtx]"]]]' -
3d Transformation from EPSG:3631(NC StatePlane)/MLLW to NAD83/MLLW.
vp = VyperPoints() x = np.array([898745.505, 898736.854, 898728.203]) y = np.array([256015.372, 256003.991, 255992.610]) z = np.array([10.5, 11.0, 11.5]) # here we use input horizontal/vertical datums for both input and output datum vp.transform_points((3631, 'mllw'), (6319, 'mllw'), x, y, z=z) vp.x Out: array([-75.7918, -75.7919, -75.792 ]) vp.y Out: array([36.0157, 36.0156, 36.0155]) vp.z Out: array([10.5, 11. , 11.5]) vp.unc Out: array([0.028, 0.028, 0.028]) -
GeoTIFF transformation - GeoTIFF with horizontal=EPSG:26919, vertical=NAD83(2011) height (assumed) to EPSG:26919/MLLW.
from vyperdatum.raster import VyperRaster new_file = r"C:\data\tiff\output.tiff" test_file = r"C:\data\tiff\test.tiff" # source EPSG:26919 read automatically, NAD83 height assumed vr = VyperRaster(test_file) # optional step saying the raster is at horiz=26919, vert=ellipse # vr.set_input_datum(26919, 'ellipse') # output=mllw input=ellipse layers, layernames, layernodata = vr.transform_raster('mllw', 'ellipse', allow_points_outside_coverage=True, output_filename=new_file) print(vr.out_crs.to_compound_wkt()) COMPOUNDCRS["NAD83 / UTM zone 19N + mllw", PROJCRS["NAD83 / UTM zone 19N", BASEGEOGCRS["NAD83",DATUM["North American Datum 1983",ELLIPSOID["GRS 1980",6378137,298.257222101,LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4269]], CONVERSION["UTM zone 19N",METHOD["Transverse Mercator",ID["EPSG",9807]], PARAMETER["Latitude of natural origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]], PARAMETER["Longitude of natural origin",-69,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]], PARAMETER["Scale factor at natural origin",0.9996,SCALEUNIT["unity",1],ID["EPSG",8805]], PARAMETER["False easting",500000,LENGTHUNIT["metre",1],ID["EPSG",8806]], PARAMETER["False northing",0,LENGTHUNIT["metre",1],ID["EPSG",8807]]],CS[Cartesian,2], AXIS["easting",east,ORDER[1],LENGTHUNIT["metre",1]], AXIS["northing",north,ORDER[2],LENGTHUNIT["metre",1]],ID["EPSG",26919]], VERTCRS["mllw", VDATUM["mllw"], CS[vertical,1],AXIS["gravity-related height (H)",up,LENGTHUNIT["metre",1,ID["EPSG",9001]]], REMARK["vdatum=vdatum_4.1.2_20201203,vyperdatum=0.1.6,base_datum=[NAD83(2011)], regions=[MENHMAgome23_8301], pipelines=[+proj=pipeline +step +proj=vgridshift grids=core\\geoid12b\\g2012bu0.gtx +step +inv +proj=vgridshift grids=MENHMAgome23_8301\\tss.gtx +step +proj=vgridshift grids=MENHMAgome23_8301\\mllw.gtx]"]]]'