US Forest Atlas FIA Modeled Abundance (Image Service)

FIA Modeled Abundance:This dataset portrays the live tree mean basal area (square feet per acre) of the species across the contiguous United States. The underlying data publication contains raster maps of live tree basal area for each tree species along with corresponding assessment data. An efficient approach for mapping multiple individual tree species over large spatial domains was used to develop these raster datasets. The method integrates vegetation phenology derived from MODIS imagery and raster data describing relevant environmental parameters with extensive field plot data of tree species basal area to create maps of tree species abundance and distribution at a 250-meter (m) pixel size for the contiguous United States. The approach uses the modeling techniques of k-nearest neighbors and canonical correspondence analysis, where model predictions are calculated using a weighting of nearest neighbors based on proximity in a feature space derived from the model. The approach also utilizes a stratification derived from the 2001 National Land-Cover Database tree canopy cover layer. This data depicts current species abundance and distribution across the contiguous United States, modeled by using FIA field plot data. Although the absolute values associated with the maps differ from species to species, the highest values within each map are always associated with darker colors. This is a digital representation of maps by Elbert L. Little, Jr., published between 1971 and 1977. These maps were based on botanical lists, forest surveys, field notes and herbarium specimens.This record was taken from the USDA Enterprise Data Inventory that feeds into the https://data.gov catalog. Data for this record includes the following resources: ISO-19139 metadata ArcGIS Hub Dataset ArcGIS GeoService For complete information, please visit https://data.gov.FIA模拟丰度数据集：本数据集呈现了美国本土范围内各树种的活立木平均断面积（平方英尺/英亩）。其关联的数据出版物包含各树种活立木断面积的栅格地图与对应评估数据。本批栅格数据集采用适用于大空间尺度下多树种制图的高效方法构建。该方法整合了源自中分辨率成像光谱仪（MODIS）影像的植被物候数据、描述相关环境参数的栅格数据，以及大量树种断面积野外样地数据，以250米的像元分辨率生成美国本土范围内的树种丰度与分布地图。该方法采用k近邻（k-nearest neighbors）与典范对应分析（canonical correspondence analysis）建模技术，基于模型导出的特征空间中的邻近性对近邻样本进行加权，以此计算模型预测结果。此外，该方法还采用了源自2001年全国土地覆盖数据库的树冠覆盖图层进行分层处理。本数据集基于FIA野外样地数据建模，呈现了当前美国本土范围内的树种丰度与分布状况。尽管各树种对应的地图绝对数值存在差异，但每张地图中的最高值始终以更深的色彩展示。本数据集是小埃尔伯特·L·利特尔（Elbert L. Little, Jr.）于1971年至1977年间出版的原版地图的数字化复刻版本，这些原始地图基于植物名录、森林调查数据、野外记录与标本馆标本制作而成。本数据集记录源自美国农业部（USDA）企业数据清单，该清单的数据会汇入https://data.gov目录。本记录包含以下资源：ISO-19139元数据、ArcGIS Hub数据集、ArcGIS地理服务（ArcGIS GeoService）。如需获取完整信息，请访问https://data.gov。