NASA ASTER Level 1T

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an advanced multispectral imager that was launched on board NASA's Terra spacecraft in December, 1999. The ASTER Level-1T (L1T) data incorporate radiometric and geometric corrections while employing ASTER 30-meter Global Digital Elevation Model (DEM) for topographic accuracy. All of these data are stored together with metadata in one HDF file. The L1T image is projected onto a rotated map (rotated to path oriented coordinate) at full instrument resolutions. The Level-1T data generation also includes registration of the SWIR and TIR data to the VNIR data. And in addition, for SWIR in particular, the parallax errors due to the spatial locations of all of its bands are corrected. The Level-1T data set provide scaled or calibrated radiance values. Scenes with sufficient elevation and ground control data for terrain correction are processed to Level 1T.

先进星载热发射与反射辐射计（Advanced Spaceborne Thermal Emission and Reflection Radiometer，ASTER）是一款先进多光谱成像仪，于1999年12月搭载美国国家航空航天局（National Aeronautics and Space Administration，NASA）的泰拉（Terra）航天器发射升空。ASTER的Level-1T（L1T）级数据在采用ASTER 30米分辨率全球数字高程模型（Digital Elevation Model，DEM）保障地形精度的同时，集成了辐射校正与几何校正处理。所有此类数据均与元数据一同存储于单个HDF文件中。L1T级影像以仪器全分辨率投影至旋转后的路径定向坐标系。Level-1T级数据的生成还包括将短波红外（Short-Wave Infrared，SWIR）与热红外（Thermal Infrared，TIR）数据配准至可见近红外（Visible and Near-Infrared，VNIR）数据。此外，针对短波红外波段，其所有波段因空间位置差异产生的视差误差均已得到校正。Level-1T级数据集提供经过定标或缩放后的辐射亮度值。具备充足高程与地面控制点数据以完成地形校正的影像，将被处理为Level 1T级数据。