A Java implementation of RDNAPTRANS™2018 (the RD + NAP to/from ETRS89 transformation) embedded in a simple REST API.

This project was inspired by a discussion about a PHP RDNAPTRANS™2018 implementation on a Dutch forum for geodata users. The RDNAPTRANS™2018 implementation is based on this SAS RDNAPTRANS™2018 implementation.

The transformation within the bounds of the correction grids (latitude 50-56°, longitude 2-8°) meets the RDNAPTRANS™2018 specifications as tested by the Validation Service of RDNAPTRANS™2018. The permission to use the RDNAPTRANS™2018 trademark has been granted on 13-10-2022.

• West of x=0 the RDNAP to ETRS89 transformation is incorrect due to an imcomplete implementation of Formula 2.2.3c of the RDNAPTRANS documentation.
• Several parts in the Transformer code compare coordinates, i.e. floating point values, to determine whether the point of interest is an edge-case (exactly the "central point Amersfoort", or a point on the opposite side of the sphere). A tolerance should be used to do a correct comparison, but this has not been implemented yet.

MIT