Delta-X: Ecogeomorphic Cell Products across the MRD, LA, USA, 2021

This product delineates the Mississippi River Delta (MRD) landscape into distinct ecogeomorphic cells, which are small contiguous areas of land with similar ecological and geomorphological characteristics. The study area is the Atchafalaya and Terrebonne basins of the MRD in southern Louisiana, U.S., which was the focus of NASA's 2021 Delta-X campaign. Each ecogeomorphic cell is a small homogeneous area of similar vegetation and elevation (or bathymetry). A "cell" typically consists of a cluster of contiguous pixels in a raster image, although cells of single pixels are present. The elevation was derived from the USGS Digital Elevation Model, and the vegetation was characterized by its spectral signature as measured by near infrared (NIR) reflectance and normalized difference vegetation index (NDVI). NIR and NDVI were computed from Sentinel-2 images acquired January through September 2021. The data are provided in shapefile and GeoTIFF formats. The vector shapefiles contain the distinct ecogeomorphic cells as polygons with unique labels (i.e., ID number). A raster image of these ecogeomorphic cells provided wherein the pixel values are the polygon labels from the shapefiles. The GeoTIFFs hold the mean and standard deviations of bathymetry, NIR, and NDVI spectral indices within each ecogeomorphic region (polygon). The raster data are provided with a spatial resolution of 0.000045 degrees (approximately 5 meters).

本产品将密西西比河三角洲（MRD）景观划分为独特的生态地貌单元，这些单元为具有相似生态和地貌特征的连续陆地小区域。研究区域位于美国路易斯安那州南部的阿查法拉亚和特雷布恩盆地，该区域是NASA 2021 年Delta-X活动的研究焦点。每个生态地貌单元是一个具有相似植被和海拔（或水深）的均质小区域。一个“单元”通常由栅格图像中连续像素簇组成，尽管也存在单个像素的单元。海拔数据源自美国地质调查局（USGS）数字高程模型，植被特征通过近红外（NIR）反射率和归一化植被指数（NDVI）进行表征。NIR 和 NDVI 是从2021年1月至9月获取的哨兵-2号图像中计算得出的。数据以shapefile和GeoTIFF格式提供。矢量shapefile包含具有唯一标签（即ID号）的多边形形式的特定生态地貌单元。提供了这些生态地貌单元的栅格图像，其中像素值来自shapefile中的多边形标签。GeoTIFF文件包含了每个生态地貌区域（多边形）内水深、NIR和NDVI光谱指数的平均值和标准差。栅格数据以0.000045度的空间分辨率提供（约5米）。