RDNAP for Debian
================
Kadaster and Rijkswaterstaat CIV, working together under the name RDNAP,
developed RDNAPTRANSTM2008, the precise and official transformation
between ETRS89 and the dutch national horizontal and vertical coordinate
reference systems the Stelsel van de Rijksdriehoeksmeting (RD) and the
Normaal Amsterdams Peil (NAP).
The Kadaster website has some general information (in dutch) about RDNAP
transformation at:
https://www.kadaster.nl/transformatie-van-coordinaten
To download the RDNAPTRANSTM2008.zip file you need to fill in a form that
requires your name, email address and phone number, before you're sent a
link to the download page via email.
Direct links to the relevant pages:
- RDNAPTRANS2008 request form
https://formulieren.kadaster.nl/aanvragen_rdnaptrans2008
- RDNAPTRANS2008 download page
https://www.kadaster.nl/rdnaptrans2008-download-
- RDNAPTRANS2008.zip file
https://www.kadaster.nl/documents/20838/87996/RDNAPTRANS2008/93c6e723-9e85-4b9d-abcb-a569e447d564
The license contained in the RDNAPTRANS2008.zip file is problematic, because
it doesn't allow distribution. The license is documented in the file
"Use of RDNAPTRANS2008.doc" (use `antiword "Use of RDNAPTRANS2008.doc"` to
display it in a terminal). Quote:
"
Use of the name RDNAPTRANSTM2008
Kadaster and Rijkswaterstaat DID, working together under the name RDNAP,
developed RDNAPTRANSTM2008 the precise and official transformation between
ETRS89 and RD/NAP for the Netherlands. This transformation will replace
RDNAPTRANSTM2008 as a result of a re-adjustment of the ETRS89 coordinates
of the AGRS.NL-stations. The validity of RDNAPTRANSTM2008 will start 25-04-
2009. The validity of RDNAPTRANSTM2004 will stop 1-4-2010.
RDNAP makes the program rdnaptrans2008 and accessory data files for
RDNAPTRANSTM2008 freely available under the following conditions:
1. rdnaptrans2008 gives examples of routines for the transformation.
RDNAP is not responsible for the correctness of a program using these
routines.
2. rdnaptrans2008 may not be distributed to others.
3. The trademark in RDNAPTRANSTM2008 indicates that all rights on the use
of this name are in the hands of Kadaster and DID.
A written permission for the use of the name RDNAPTRANSTM2008 can be
obtained by sending this completely filled in sheet to:
RDNAP p/a
Kadaster GEO/MB/GRS
P.O. box 9046
7300 GH Apeldoorn
or fax to:
0031 (0)88 183 2079
.
.
The permission for the use of the name RDNAPTRANSTM2008 can be stopped by
RDNAP at any moment when the software does not meet the specifications as
mentioned at the RDNAPTRANSTM2008 test sheet in the appendix.
"
The RDNAPTRANS2008.zip file contains another zip file: NTv2_2008.zip. The
NTv2_2008.zip file contains a different license which limits modification
but allows distribution. The license is documented in the file
"Use of RDTRANS2008 and NAPTRANS2008.pdf" (use
`pdf2txt "Use of RDTRANS2008 and NAPTRANS2008.pdf"` to display it in a
terminal). Quote:
"
License
RDNAP makes the rdtrans2008.gsb and naptrans.gtx grid correction files
freely available.
Implementation and distribution of the rdtrans2008 NTv2-grid and
naptrans2008 VDatum-grid in combination with other tools/software that
require these grids for transformation between ETRS89 and RD/NAP is allowed,
under the following conditions:
1. It is not allowed to modify the correction values of the grid
correction files. (It is allowed to convert the grid data to a
different file format or data structure as long as this does not
affect the results of the calculations.)
2. It should be clear from the documentation of the software using the
grid correction files that the transformation procedure using the grid
correction files is not identical to RDNAPTRANS™2008.
3. The correct implementation of the grid corrections has to be tested as
specified in Appendix 2
Disclaimer
The correction grids for RD and NAP in NTv2 and VDatum format are provided
‘as is’ and any express or implied warranties, including, but not limited
to, the implied warranties of merchantability and fitness for a particular
purpose are disclaimed. In no event shall Kadaster or Rijkswaterstaat be
liable for any direct, indirect, incidental, special, exemplary or
consequential damages (including but not limited to procurement of substitute
goods or services, loss of use, data or profits, or business interruption)
however caused and on any theory of liability, whether in contract, strict
liability, or tort (including negligence or otherwise) arising in any way out
of the use of the correction grids for RD and NAP in NTv2 and Vdatum format.”
"
The get-orig-source script downloads the RDNAPTRANS2008.zip file, extracts
the content of NTv2_2008.zip file from within it, and creates a tarball
from the NTv2_2008.zip file content (documentation in PDF and grid files).
To use the grid correction files the definitions as suggested by Kadaster
are available in the /usr/share/proj/rdnap file:
# RDNAP with NTv2 and VDatum
<rdnap> +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +nadgrids=rdtrans2008.gsb +geoidgrids=naptrans2008.gtx +units=m +no_defs <>
# RD with NTv2 only
<rd> +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +nadgrids=rdtrans2008.gsb +units=m +no_defs <>
These were suggested by Lennard Huisman from Kadaster on the Dutch OSGeo
mailinglist:
https://lists.osgeo.org/pipermail/dutch/2014-October/000975.html
To use these definitions with cs2s specify the rnap file:
cs2cs +init=rdnap:rdnap +to +init=epsg:4258
cs2cs +init=rdnap:rd +to +init=epsg:4258
Beware that the transformation procedure is not identical to RDNAPTRANS™2008.
The file "Use of RDTRANS2008 and NAPTRANS2008.pdf" documents a list of
limitations of the procedure with NTv2 grid correction files. Quote:
"
1) The rdtrans2008 NTv2-grid can only give identical results to
RDNAPTRANS™2008 within 1 millimeter at ground level onshore and
at mean seal level offshore. The horizontal deviation is
approximately 1 millimeter per 50 meter height difference from
ground level or mean sea level.
2) An exception to 1) is the border of the RDNAPTRANS™2008 correction
grid. Transformation results within cells of the rdtrans2008
NTv2-grid that are intersected by the border of the RDNAPTRANS™2008
correction grid can result in deviations of up to 20 centimeter.
3) The naptrans2008 VDatum-grid cannot be used to determine deflections
of the vertical. For this the NLGEO2004 geoid model has to be used.
4) The naptrans2008 VDatum-grid is referenced to the Bessel-1841
ellipsoid and cannot be used stand-alone, it has to be used in
combination with the rdtrans2008 NTv2-grid.
"
The package build includes the mandatory tests documented in Appendix 2 of
"Use of RDTRANS2008 and NAPTRANS2008.pdf". The tests compare the coordinate
transformations by cs2cs to those computed with RDNAPTRANS™2008.
The transformations by cs2cs produce different results, not identical to
RDNAPTRANS™2008. The tests only fail if the difference is greater than
the margin.