We present a GIS-based crowdsourcing application that was launched soon after the first COVID-19 cases had been recorded in Greece, motivated by the need for fast, location-wise data acquisition regarding COVID-19 disease spread during spring 2020, due to limited testing. A single question was posted through a web App, to which the anonymous participants subjectively answered whether or not they had experienced any COVID-19 disease symptoms. Our main goal was to locate geographical areas with increased number of people feeling the symptoms and to determine any temporal changes in the statistics of the survey entries. It was found that the application was rapidly disseminated to the entire Greek territory via social media, having, thus, a great public reception. The higher percentages of participants experiencing symptoms coincided geographically with the highly populated urban areas, having also increased numbers of confirmed cases, while temporal variations were detected that accorded with the restrictions of activities. This application demonstrates that health systems can use crowdsourcing applications that assure anonymity, as an alternative to tracing apps, to identify possible hot spots and to reach and warn the public within a short time interval, increasing at the same time their situational awareness. However, a continuous reminder for participation should be scheduled.

中文翻译：

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众包是海量数据采集的可靠方法吗？2020年春季在希腊传播的COVID-19案例

我们提出了一个基于GIS的众包应用程序，该应用程序在希腊记录了第一批COVID-19病例后不久就启动了，这是由于受限于有限的原因，需要在2020年春季快速，按地点获取有关COVID-19疾病传播的数据测试。通过网络应用程序发布了一个问题，匿名参与者在此问题上主观回答了他们是否经历过任何COVID-19疾病症状。我们的主要目标是确定出现症状的人数增加的地理区域，并确定调查条目统计信息的时间变化。结果发现，该应用程序已通过社交媒体迅速传播到整个希腊领土，因此受到了广泛的公众欢迎。出现症状的参加者的百分比较高，在地理上与人口稠密的城市地区相吻合，确诊病例的数量也在增加，同时发现时间上的变化符合活动的限制。此应用程序演示了卫生系统可以使用确保匿名的众包应用程序（作为跟踪应用程序的替代方法）来识别可能的热点并在短时间内间隔内并向公众发出警告，同时提高他们的态势感知能力。但是，应该安排持续提醒参加者。此应用程序演示了卫生系统可以使用确保匿名的众包应用程序（作为跟踪应用程序的替代方法）来识别可能的热点并在短时间内间隔内并向公众发出警告，同时提高他们的态势感知能力。但是，应该安排持续提醒参加者。此应用程序演示了卫生系统可以使用确保匿名的众包应用程序（作为跟踪应用程序的替代方法）来识别可能的热点并在短时间内间隔内并向公众发出警告，同时提高他们的态势感知能力。但是，应该安排持续提醒参加者。