National Indicative Aggregated Fire Extent Dataset 2019-2020 - v20200324

The National Indicative Aggregated Fire Extent Dataset has been developed rapidly to support the immediate needs of the Department of Agriculture, Water and the Environment (DAWE) in:\r\na) quantifying the potential impacts of the 2019/20 bushfires on wildlife, plants and ecological communities;and,\r\nb) identifying appropriate response and recovery actions.\r\n\r\nThe intent was to derive a reliable, agreed, fit for purpose and repeatable national dataset of burnt areas across Australia for the 2019/20 bushfire season.\r\nThe dataset takes the national Emergency Management Spatial Information Network Australia (EMSINA) data service, which is the official fire extent currently used by the Commonwealth, and adds supplementary data from other sources to form a cumulative national view of fire extent. This EMSINA data service shows the current active fire incidents, and the Department map shows the total fire extent from 1 July 2019 to the 23 March 2020.\r\nEMSINA have been instrumental in providing advice on access to data and where to make contact in the early stages of developing the National Indicative Aggregated Fire Extent Dataset.\r\nThis dataset is released on behalf of the Commonwealth Government and endorsed by the National Burnt Area Dataset Working Group, convened by the National Bushfire Recovery Agency.\r\n\r\nKnown Issues:\r\nThe dataset has a number of known issues, both in its conceptual design and in the quality of its inputs. These are outlined below and should be taken into account in interpreting the data and developing any derived analyses.\r\nThe list of known issues below is not comprehensive: it is anticipated that further issues will be identified in the future, and the Department welcomes feedback on this. We will seek as far as possible to continuously improve the dataset in future versions.\r\nIn addition, the 2019/20 bushfire season is ongoing and it can be expected that the fire extent will increase. Future versions of the dataset will therefore document and distinguish between changes arising from methodological improvement, as distinct from changes to the actual fire extent.\r\n1. The dataset draws data together from multiple different sources, including from state and territory agencies responsible for emergency and natural resource management, and from the Northern Australian Fire Information website. The variety of mapping methods means that conceptually the dataset lacks national coherency.\r\n2. The limitations associated with the input datasets are carried through to this dataset. Users are advised to refer to the input datasets’ documentation to better understand limitations.\r\n3. The dataset is intentionally precautionary and the rulesets for its creation elect to accept the risk of overstating the size of particular burnt areas. If and when there are overlapping polygons for an area, the internal boundaries have been dissolved.\r\n4. The dataset shows only the outline of burnt areas and lacks information on fire severity in these areas, which may often include areas within them that are completely unburnt. For the intended purpose this may limit the usability of the data, particularly informing on local environmental impacts and response. This issue will be given priority, either for future versions of the dataset or for development of a separate, but related, fire severity product.\r\n5. This continental dataset includes large burnt areas, particularly in northern Australia, which can be considered part of the natural landscape dynamics. For the intended purpose of informing on fire of potential environmental impact, some interpretation and filtering may be required. There are a variety of ways to do this, including by limiting the analysis to southern Australia, as was done for recent Wildlife and Threatened Species Bushfire Recovery Expert Panel’s preliminary analysis of 13 January 2020. For that preliminary analysis area, boundaries from the Interim Biogeographic Regionalisation of Australia version 7 were used by the Department to delineate an area of southern Australia encompassing the emergency bushfire areas of the southern summer. The Department will work in consultation with the expert panel and other relevant bodies in the future on alternative approaches to defining, spatially or otherwise, fire of potential environmental impact.\r\n6. The dataset cannot be used to reliably recreate what the national burnt area extent was at a given date prior to the date of release. Reasons for this include that information on the date/time on individual fires may or may not have been provided in the input datasets, and then lost as part of the dissolve process discussed in issue 2 above.\r\n7. With fires still burning extents are not yet refined.\r\n8. Fire extents are downloaded daily and datasets are aggregated. This results in an overlap of polygon extents and raises the issue that refined extents are disregarded at this early stage.\r\n9. The NAFI dataset is only current to 18 March 2020.

国家指示性聚合过火范围数据集（National Indicative Aggregated Fire Extent Dataset）旨在快速开发，以满足农业、水资源与环境部（Department of Agriculture, Water and the Environment, DAWE）的以下迫切需求：
a）量化2019/20年丛林大火对野生动物、植物及生态群落的潜在影响；
b）确定适宜的应对与恢复措施。

本数据集旨在为2019/20年丛林大火季生成一套可靠、统一、符合用途且可复现的澳大利亚全国过火区域数据集。
本数据集以联邦政府目前使用的官方过火范围数据服务——澳大利亚应急管理空间信息网（Emergency Management Spatial Information Network Australia, EMSINA）为基础，补充其他来源的辅助数据，从而形成全国范围的累积过火范围视图。该EMSINA数据服务可展示当前活跃的火灾事件，而该部制作的地图则展示了2019年7月1日至2020年3月23日期间的总过火范围。
EMSINA在本数据集开发初期，为数据获取渠道及联络方式提供了关键指导。
本数据集由联邦政府代表发布，并经由国家丛林大火恢复署召集的全国过火区域数据集工作组审核认可。

已知问题：
本数据集在概念设计与输入数据质量两方面均存在若干已知问题，下文将逐一列明，在解读数据及开展衍生分析时请务必予以考虑。
下述已知问题清单并非穷尽式列举：预计未来还会发现更多问题，该部欢迎各界就此提供反馈。我们将尽可能在后续版本中持续优化本数据集。
此外，2019/20年丛林大火季仍在持续，过火范围预计还会扩大。因此，本数据集的后续版本将对两类变化进行区分记录：一类源于方法学改进，另一类则源于实际过火范围的变化。

1. 本数据集整合了多类来源的数据，包括负责应急与自然资源管理的各州及领地机构数据，以及北澳大利亚火灾信息网站（Northern Australian Fire Information）的数据。由于采用了多样的制图方法，本数据集在概念上缺乏全国统一性。
2. 输入数据集本身存在的局限性会被带入本数据集。建议用户参考输入数据集的相关文档，以更全面地了解其局限性。
3. 本数据集采用了预防性原则，其制作规则选择接受部分过火区域面积被高估的风险。当某一区域存在重叠多边形时，内部边界将被合并消解。
4. 本数据集仅展示过火区域的轮廓，未包含这些区域的火灾烈度信息——而过火区域内部往往存在完全未被烧毁的区域。就其预设用途而言，这一局限可能会降低数据的可用性，尤其是在用于评估当地环境影响及制定应对措施时。本问题将被优先处理，要么在本数据集的后续版本中完善，要么开发一款独立但相关的火灾烈度产品。
5. 本大陆级数据集包含大面积过火区域，尤其是澳大利亚北部地区，这类区域可被视为自然景观动态的一部分。就其用于评估具有潜在环境影响的火灾这一预设用途而言，需要对数据进行一定的解读与筛选。筛选方式多种多样，例如将分析范围限定在澳大利亚南部，正如2020年1月13日野生动物与濒危物种丛林大火恢复专家小组开展的初步分析所做的那样。针对该初步分析的区域，该部采用了澳大利亚临时生物地理分区第7版（Interim Biogeographic Regionalisation of Australia version 7）的边界，划定了涵盖南部夏季应急丛林大火区域的澳大利亚南部范围。未来，该部将与专家小组及其他相关机构协商，探索在空间或其他维度上定义具有潜在环境影响的火灾的替代方案。
6. 本数据集无法可靠还原发布日期之前任意给定时间点的全国过火范围。原因包括：输入数据集可能提供也可能未提供单起火灾的日期/时间信息，而这些信息会在上述第2条提及的边界合并流程中丢失。
7. 目前仍有火灾在燃烧，过火范围尚未经精细化处理。
8. 过火范围数据每日下载并聚合，这会导致多边形范围出现重叠，进而造成该阶段的精细化范围被忽略的问题。
9. 北澳大利亚火灾信息（Northern Australian Fire Information, NAFI）数据集的更新截止至2020年3月18日。