GLW

Livestock contributes directly to the livelihoods and food security of almost a billion people and affects the diet and health of many more. With estimated standing populations of 1.43 billion cattle, 1.87 billion sheep and goats, 0.98 billion pigs, and 19.60 billion chickens, reliable and accessible information on the distribution and abundance of livestock is needed for a many reasons. These include analyses of the social and economic aspects of the livestock sector; the environmental impacts of livestock such as the production and management of waste, greenhouse gas emissions and livestock-related land-use change; and large-scale public health and epidemiological investigations. The Gridded Livestock of the World (GLW) database, produced in 2007, provided modelled livestock densities of the world, adjusted to match official (FAOSTAT) national estimates for the reference year 2005, at a spatial resolution of 3 minutes of arc (about 5×5 km at the equator). Recent methodological improvements have significantly enhanced these distributions: more up-to date and detailed sub-national livestock statistics have been collected; a new, higher resolution set of predictor variables is used; and the analytical procedure has been revised and extended to include a more systematic assessment of model accuracy and the representation of uncertainties associated with the predictions.

畜牧业直接支撑近10亿人口的生计与粮食安全，更对更多人群的饮食与健康产生重要影响。据估算，全球存栏牛14.3亿头、绵羊与山羊18.7亿只、生猪9.8亿头、家禽196亿只。出于多方面需求，亟需获取可靠且可及的畜禽分布与丰度信息，此类需求涵盖：畜牧业部门的社会与经济维度分析、畜禽养殖的环境影响评估（如废弃物产生与管理、温室气体排放、畜禽养殖相关土地利用变化），以及大规模公共卫生与流行病学调查。2007年发布的《全球栅格化畜禽数据集》（Gridded Livestock of the World, GLW），以3角分的空间分辨率（赤道区域约5×5千米）提供了全球畜禽养殖密度模型数据，并经校准以匹配参考年份2005年的官方（FAOSTAT）国家统计估算值。近年来方法学层面的改进显著优化了该数据集：研究团队收集了更新、更细致的地方级畜禽统计数据，采用了一套全新的高分辨率预测变量集，并对分析流程进行了修订与扩展，新增了对模型精度的系统性评估，以及对预测结果相关不确定性的表征。

搜集汇总

背景与挑战

背景概述

GLW数据集提供了全球牲畜（包括牛、羊、猪和鸡等）的分布和数量网格化数据，空间分辨率为3弧分钟，适用于社会经济、环境和公共卫生研究。数据集基于2005年的官方统计数据，并经过方法改进以提高准确性。