AUSGeoid98 v.1.0 data files: (sl52-04)

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 Data format: AUSGeoid98 data files have a header record at the start of each file, to distinguish them from the superseded AUSGeoid93 data files. AUSGeoid98 data files show the geoid-ellipsoid separation to 3 decimal places, while the superseded AUSGeoid93 data files showed only 2 decimal places.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弧分格网数据集，可用于对指定点位的大地水准面-椭球面分离值（geoid-ellipsoid separations）进行插值计算。用户可自行选用插值软件，也可使用澳大利亚地球科学局（Geoscience Australia）推出的Windows平台插值工具Winter。
该数据文件采用标准格式的文本文件，覆盖范围与标准地形图图幅一致。当前可获取两种比例尺的图幅数据：1:250,000（约100×150千米）与1:1,000,000（约400×600千米），且每个图幅的四周均设有4弧分的重叠区域。
数据格式规范如下：每个文件的起始位置均带有头部记录，用于与已废止的AUSGeoid93数据文件进行区分。AUSGeoid98数据文件的大地水准面-椭球面分离值精确至小数点后三位，而已废止的AUSGeoid93数据文件仅精确至小数点后两位。AUSGeoid98的垂线偏差基于大地水准面-椭球面分离曲面计算得到，而AUSGeoid93的垂线偏差则以OSU91A模型为计算依据。