The files in this package can be unpacked in the PROJ data directory. For an installed PROJ this may be /usr/local/share/proj or /usr/share/proj on unix style operating systems.
About the North America PROJ resource package
The North America PROJ resource package is a collections of grids and init-files that are not essential for the functionality of PROJ but still of general interest to PROJ-users in the region specific to the package.
Canada: NAD27 -> NAD83
Transform between NAD27 and NAD83 in Canada.
Greenland: GRS80 ellipsoidal heights -> GVR2016
Transform ellipsoidal heights to the local height system GVR2016. The horizontal grid coordinates are referenced to GR96.
Greenland: GRS80 ellipsoidal heights -> GVR2000
Transform ellipsoidal heights to the local height system GVR2000. The horizontal grid coordinates are referenced to GR96.
USA: NAD83 -> NAD83 (HARN/HPGN)
Source: .los/.las files coming from NOAA Format: NTv2 License: Public Domain
Grid data for high precision conversion of geographic coordinates from the original NAD83 (1986) (EPSG:4269) to NAD83 High Precision Geodetic Networks (HPGNs) (EPSG:4152), also referred to as High Accuracy Reference Networks (HARNs). NAD 83 coordinates based on the HPGN/HARN surveys changed approximately 0.2 to 1.0 meter relative to the original NAD 83 (1986) adjustment.
Those files have been converted to NTv2 grids with the build_nad83_harn.sh script.
- *hpgn.gsb (51 files)
Continental USA VERTCON: NGVD (19)29 height to NAVD (19)88 height
Source: converted from NOAA VERTCON .94 grids Converter: vertcon_94_to_gtx.py Format: GTX License: Public Domain
Transform NGVD (19)29 height to NAVD (19)88 height. The .gtx files contain the offset (in millimeter) to add to NGVD 29 heights to get NAVD 88 heights.
So with PROJ 5.2, to convert from NGVD 29 to NAVD 88, you need to a multiplication by 0.001 to convert from millimeter to meter: +proj=pipeline +step=vgridshift +multiplier=0.001 +grids=vertconw.gtx,vertconc.gtx,vertcone.gtx
The horizontal grid coordinates may be referenced to NAD27 or NAD83
USA GEOID12B model: NAD83(2011)/NAD83(MA11)/NAD83(PA11) to NAVD88/PRVD02/VIVD09/GUVD04/NMVD03/ASVD02 height
Source: converted from NOAA NGS .bin grids Converter: build_g2012.sh Format: GTX License: Public Domain
GEOID12B is a hybrid geoid height model that can transform between a NAD 83 ellipsoid height and the relevant vertical datum for each region. See https://www.ngs.noaa.gov/GEOID/GEOID12B/faq_2012B.shtml for more details.
- g2012bu0.gtx : Conterminous US, referenced to NAD83(2011). Vertical datum: NAVD88
- g2012ba0.gtx : Alaska, referenced to NAD83(2011). Vertical datum: NAVD88
- g2012bh0.gtx : Hawaii, referenced to NAD83(PA11). Vertical datum: identical to that of USGG2012, which is offset by 50-60 cm from some Local Tidal bench mark values.
- g2012bg0.gtx : Guam and Northern Mariana Islands, referenced to NAD83(PA11). Vertical datum: GUVD04/NMVD03
- g2012bs0.gtx : American Samoa, referenced to NAD83 (PA11). Vertical datum: ASVD02
- g2012bp0.gtx : Puerto Rico / U.S. Vigin Islands, referenced to NAD83(2011). Vertical datum: PRVD02 and VIVD09
Greenland: System definitions related to GR96
Init files with various transformations and conversions of relevance in Greenland. All definitions in the init file uses the local GR96 reference frame as a pivot datum. More information can be found in the NordicTransformations repository.