A global reference database of crowdsourced cropland data collected using the Geo-Wiki platform

A global reference dataset on cropland was collected through a crowdsourcing campaign implemented using Geo-Wiki. This reference dataset is based on a systematic sample at latitude and longitude intersections, enhanced in locations where the cropland probability varies between 25-75% for a better representation of cropland globally. Over a three week period, around 36K samples of cropland were collected. For the purpose of quality assessment, additional datasets are provided. One is a control dataset of 1793 sample locations that have been validated by students trained in image interpretation. This dataset was used to assess the quality of the crowd validations as the campaign progressed. Another set of data contains 60 expert or gold standard validations for additional evaluation of the quality of the participants. These three datasets have two parts, one showing cropland only and one where it is compiled per location and user. This reference dataset will be used to validate and compare medium and high resolution cropland maps that have been generated using remote sensing. The dataset can also be used to train classification algorithms in developing new maps of land cover and cropland extent.

本数据集为全球耕地参考数据集，通过依托Geo-Wiki平台开展的众包任务采集获取。该参考数据集以经纬度交点处的系统采样为基础，并针对耕地概率处于25%至75%区间的区域进行了采样增强，以实现全球耕地分布的更优表征。本次采集任务历时三周，共获取约3.6万个耕地样本。为开展质量评估，本数据集配套提供了额外的验证数据集：其一为包含1793个采样点的对照数据集，所有采样点均由接受过图像解译培训的学生完成验证，该数据集用于在众包任务推进过程中评估大众验证结果的质量；其二为包含60份专家验证或金标准验证结果的数据集，用于额外评估参与众包任务的人员的验证质量。上述三类数据集均包含两个子部分：其一仅标注耕地属性，其二则按采样点位与参与用户进行汇总整合。本参考数据集将用于验证并对比基于遥感技术生成的中、高分辨率耕地分布图；此外，该数据集还可用于训练分类算法，以助力生成全新的土地覆盖与耕地范围分布图。