全球农田的新地图

新地图was released today以最高分辨率详细介绍全世界的农田，有助于以可持续的方式确保全球粮食和水安全。

The map establishes that there are 1.87 billion hectares of croplands in the world, which is 15 to 20 percent—or 250 to 350 million hectares (Mha)—higher than former assessments. The change is due to more detailed understanding of large areas that were never mapped before or were inaccurately mapped as non-croplands.

较早的研究表明，中国或美国的农田净区域最高，但这项研究表明，印度排名第一，其中179.8 MHA（占全球农田净面积的9.6％）。第二是美国的167.8 MHA（8.9％），中国为165.2 MHA（8.8％），俄罗斯为155.8 MHA（8.3％）。可以在世界上每个国家的统计数据中查看interactive map。

由于地理总区域的农田比例，南亚和欧洲可以被视为世界上的农业首都。农田占摩尔多瓦，圣马力诺和匈牙利的80％以上；丹麦，乌克兰，爱尔兰和孟加拉国的70％至80％之间；荷兰，英国，西班牙，立陶宛，波兰，加沙地带，捷克共和国，意大利和印度的60％至70％。为了进行比较，美国和中国各有18％的农田。

该研究由USGS领导，是全球粮食安全支持分析数据 @ 30-m（GFSAD30）项目。该地图主要由Landsat satellite imagery具有30米的分辨率，这是任何全球农业数据集的最高空间分辨率。

详细监测农田的重要性

“The map clearly shows individual farm fields, big or small, at any location in the world,” said Prasad Thenkabail, USGS research geographer and Principal Investigator for the GFSAD30 Project Team. “Given the high resolution of 30 meters and 0.09 hectares per pixel, a big advantage is the ability to see croplands in any country and sub-national regions, including states, provinces, districts, counties and villages.”

With the global population nearing the 7.6 billion mark and expected to reach 10 billion by 2050, it is of increasing importance to understand and monitor the state of agriculture across the world in great detail. This new research is useful to international development organizations, farmers, decision makers, scientists and national security professionals.

“This map is a baseline and starting point for higher level assessments, such as identifying which crops are present and where, when they grow, their productivity, if lands are left fallow and whether the water source is irrigated or rain fed,” said Thenkabail. “Comparisons can be made between the present and past years as well as between one farm and another. It is invaluable to know the precise location of croplands and their dynamics to lead to informed and productive farm management.”

Critical for Assessing Water Security

该地图和随附的数据不仅具有重大的粮食安全影响，而且对于评估水安全的基准也至关重要。全世界所有人类用水中近80％都用于生产食物，这项研究提供了对“每滴作物”的见解，这是对每单位水生产的农作物数量的评估。

Research is a Major Undertaking

“The project is a major undertaking for many reasons,” said Thenkabail. “One major challenge was obtaining cloud-free images in regions such as the tropics and during rainy seasons. That took multiple years in some areas. This project required the use of satellite-acquired big-data analytics using machine learning algorithms on a cloud computing platform such as the Google Earth Engine.”

该项目的另一个重要方面是对地图的严格验证，总体准确性为92％。验证是由一个独立团队在全球72个区域进行的。

USGS领导该项目，并在提供Landsat图像中发挥了特别有价值的作用。USGS从1972年到今天，收购，流程，档案和分发（向世界上的任何人）数据。该项目使用2015年主要是Landsat卫星图像的独一无二的数据集。遥感对于实现全球视角以及客观和无偏见的信息至关重要。

View how croplands are distributed在每个国家 /地区，并通过Land Processes Distributed Active Archive Center。

GFSAD30项目团队的目标是年复一年地，迅速，一致，准确地绘制全球农田及其属性。该项目是USGS，国家航空和太空管理局的合作努力美国农业部，美国环境保护局，印度尼西亚环境系统研究所和Google。该项目由美国国家航空航天局（NASA）制造地球系统数据记录用于研究环境计划，并获得了USGS的补充资金。

This map shows cropland distribution across the world in a nominal 30-meter resolution. This is the baseline product of the GFSAD30 Project.

This map shows U.S. croplands in a nominal 30-meter resolution.

This map shows croplands in Texas in a nominal 30-meter resolution.