Matlab functions for SVY21 and WGS84 conversion. Please refer to below web for the detailed formulae, https://www.linz.govt.nz/data/geodetic-services/coordinate-conversion/projection-conversions/transverse-mercator-transformation-formulae
Infor about SVY21 Plane Coordinate System from SLA, https://www.sla.gov.sg/sirent/CoordinateSystems.aspx https://app1.sla.gov.sg/sirent/CoordinateSystems.aspx
Geoidal Model Height is useful when converting ellipsoidal height to height with reference to Singapore Height Datum (SHD). The code 'geoModN' used the formular provided by SLA in below slides to calculate the converter N. Reference slides https://fig.net/resources/proceedings/2015/2015_07_vrfp_comm5/5A_Khoo_Singapore_Height_Datum.pdf