On October 13 Rijkswaterstaat AGI and Kadaster presented the new transformation
RDNAPTRANS2004 between ETRS89 and RD/NAP. At this occasion we announced that we
would send RDNAPTRANS2004 to all software producers that received the former
RDNAPTRANS (from 2000, but without a year number in the name) in the past.

By the end of December 2004 the RD and NAP databases will contain new adjusted
values for ETRS89 , RD and NAP-heights. From that moment on the use of
RDNAPTRANS2004 is more precise than the use of the existing RDNAPTRANS. After
all the differences do not exceed 1 cm in horizontal position and 2 cm in the
vertical. Formally the transition period is till 1-1-2006, but we would
appreciate a more rapid update of the programs if possible.

RDNAPTRANS2004 is presented to you in the form of the zip-file rdnaptrans2004.zip containing the files:

- rdnaptrans2004.xxx	The Windows executable, renamed to let it pass
firewalls etc. The program will transform only one point per run to test your
program. 

- rdnaptrans2004.cpp	source code in C++ this code is just an example to show the formulas used.

- x2c.grd		binary file with the x-RD correction grid (identical in RDNAPTRANS)

- y2c.grd		binary file with the y-RD correction grid (identical in
RDNAPTRANS)

- nlgeo04.grd		binary file with the NLGEO2004 geoid grid 

- test.txt		file with test points 

- nlgeo2004.txt		ASCII file with a format like the former geoid (De Min) but with numbers from the NLGEO2004 geoid model

- 7par.txt		ASCII file with the RDNAPTRANS2004 parameters between RD and ETRS89

In the rdnaptrans2004 program horizontal and vertical coordinates are
integrated. The region of validity is where interpolation in between grid points of x2c.grd and y2c.grd and nlgeo04.grd is possible.
Important: For those producers who do not wish to remake their program it is
only necessary to change the 7 transformation parameters (7par.txt) and the
geoid values (nlgeo2004.txt) in their RDNAPTRANS program.

Best regards,

Joop van Buren
______________________________________________________________		
Kadaster concernstaf
Afdeling Geodesie
Joop van Buren, geodetisch adviseur
Tel. 055 528 55 09, fax 528 50 36 
joop.vanburen@kadaster.nl