The high-precision levelling network (NAP) of Biscay is part of the geodetic infrastructure of the Historical Territory of Biscay. It densifies the REDNAP Project of the National Geographic Institute (IGN), which in turn is linked to the European vertical reference models (EUVN). The new sections being implemented by the Provincial Council of Biscay (BFA/DFB) comply with the specifications and quality standards of the IGN’s REDNAP. As a result, the Historical Territory of Biscay has a heterogeneous network of levelling benchmarks, including legacy IGN benchmarks, new DFB benchmarks, and benchmarks from the Basque Government (in obsolete vertical datums), which are being re-observed as part of the NAP densification campaigns.
Provincial Council of Biscay
Last Modified January 29 2026
