AUSGeoid98 v.1.0 data files: (sl55-01)

AUSGeoid98 data files contain a 2 minute grid of AUSGeoid98 data covering the Australian region, which you can use to interpolate geoid-ellipsoid separations for the positions required.You can use your own interpolation software, or you can use Geoscience Australia's Windows Interpolation software (Winter). The data files are text files in a standard format that cover the same area as standard topographic map areas. Files covering both 1:250,000 (approximately 100 x 150 km) and 1:1,000,000 (approximately 400 x 600 km) map areas are available. There is a 4 minute overlap on all sides of each area. Data format: AUSGeoid98 data files have a header record at the start of each file, to distinguish them from the superseded AUSGeoid93 data files. AUSGeoid98 data files show the geoid-ellipsoid separation to 3 decimal places, while the superseded AUSGeoid93 data files showed only 2 decimal places. AUSGeoid98 deflections of the vertical were computed from the geoid-ellipsoid separation surface, while the AUSGeoid93 deflections of the vertical were computed from OSU91A.

AUSGeoid98数据文件包含覆盖澳大利亚区域的2分网格AUSGeoid98数据，可用于对所需点位插值计算大地水准面差距（geoid-ellipsoid separation）。用户可自行选用插值软件，或使用澳大利亚地球科学局（Geoscience Australia）开发的Windows插值软件（Winter）。
该数据文件为标准格式的文本文件，其覆盖范围与标准地形图幅一致。现有覆盖1:250000（约100×150千米）及1:1000000（约400×600千米）比例尺地形图幅的数据文件。每个图幅的四周均存在4分的重叠区域。
数据格式说明：每个AUSGeoid98数据文件的起始位置均带有头部记录，用于与已被取代的AUSGeoid93数据文件区分。AUSGeoid98数据文件将大地水准面差距保留至小数点后三位，而已被取代的AUSGeoid93数据文件仅保留两位小数。AUSGeoid98的垂线偏差（deflections of the vertical）由大地水准面差距曲面计算得出，而AUSGeoid93的垂线偏差则基于OSU91A模型计算得到。