Panama Vegetation Time Series Maps

Panama Vegetation Time Series Maps for 1990-2016 with preliminary 2020 deforestation data. (the official 2020/21 map will be made available at the end of the 2021 mapping period). The following components are provided: "PVCTSYYYYvN" are 30m resolution raster maps resulting from compositing of 60-100 classified Landsat images for each time step, where YYYY is the nominal year of the compositing time period. (1991 includes images from 1987-1991. 2001 includes images from 1997-2001. 2006 includes images from 2002-2006. 2011 includes images from 2007-2011. 2016 includes images from 2012-2016.) Maps are all in GeoTiff format. "PVCTS_key.lyr" is a layer file that can be applied in ArcGIS for optimal display of categories. "PVCTSColorKey" provides more detailed description of categories and can be used to create a key in other software. More details about the land cover classes can be found in the "PVCTSv2_SupplementaryInfo" file. "PVCTSdeforest7cat_YYXX" are corresponding deforestation maps for activity occurring between years YY and XX. "Deforest7cat.lyr" provides the layer file that can be applied in ArcGIS for suggested viewing and "PVCTS_Deforestation_ColorKey" provides a description of the categories and can be used to create a key in other software. "PVCTSv2_SupplementaryInfo" provides information about the methods and data in the PVCTS composite and deforestation files. Accuracy assessments and error adjustments for the current PVCTS version are included in this document. "MaxAgeYYYY" are maximum-vegetation-age raster maps based on aggregation of clearing observations from all images in the USGS Landsat archive with cloud-cover <70%. These are 30m resolution rasters in GeoTiff format. Values indicate the maximum age that the vegetation can be in year YYYY based on the most recent clearing observation, or 99 if never observed to be cleared. A value of -1 means that the pixel was not observed to be cleared in year YYYY but it was observed to be cleared in year YYYY+1. A clearing observation occurs when the NBR (Normalized Burn Index) is below a season-based threshold (1000 to 3000) in a cloud-masked image. Many pixels are not observed each year due to cloud cover, thus these figures represent Maximum age (vegetation might be younger). The information in these layers has already been applied to the PVCTS maps, but not vice-versa (no other data is taken into account beyond NBR threshold). "metadata_spatial_ss" provides the spatial metadata for all GeoTiff files. Projection is in WGS_1984_UTM_Zone_17N.1990-2016年巴拿马植被时间序列地图及2020年初步毁林数据（官方2020/21版地图将在2021年制图周期结束后发布）。本次提供的数据集组件如下："PVCTSYYYYvN"为30米分辨率栅格地图，由每个时间步的60-100景分类后陆地卫星（Landsat）影像合成得到，其中YYYY代表合成时段的标称年份。（注：1991年版的合成时段为1987-1991年，2001年版为1997-2001年，2006年版为2002-2006年，2011年版为2007-2011年，2016年版为2012-2016年。）所有地图均采用GeoTiff格式。"PVCTS_key.lyr"是可在ArcGIS中加载的图层文件，用于实现地物类别的最优可视化显示；"PVCTSColorKey"文件提供了地物类别的详细说明，可用于在其他软件中制作分类图例。更多关于土地覆盖类别的细节可查阅"PVCTSv2_SupplementaryInfo"文件。"PVCTSdeforest7cat_YYXX"为对应YY至XX年间发生的毁林活动的配套栅格地图。"Deforest7cat.lyr"是可在ArcGIS中加载的图层文件，用于推荐的可视化查看方式；"PVCTS_Deforestation_ColorKey"则提供了毁林类别的说明，可用于在其他软件中制作图例。"PVCTSv2_SupplementaryInfo"文件涵盖了PVCTS合成产品及毁林数据的制作方法与数据源信息，同时包含当前版本PVCTS数据集的精度评估与误差校正内容。"MaxAgeYYYY"是基于美国地质调查局（USGS）Landsat档案中云量小于70%的所有影像的砍伐观测数据聚合得到的最大植被年龄栅格地图，分辨率为30米，格式为GeoTiff。其像元值代表基于最新砍伐观测结果，该植被在YYYY年份可达到的最大年龄；若从未被观测到遭受砍伐，则像元值为99。像元值为-1表示该像元在YYYY年份未被观测到遭受砍伐，但在YYYY+1年份被观测到遭受砍伐。砍伐观测的判定标准为：在经过云掩模处理的影像中，归一化燃烧指数（Normalized Burn Index, NBR）低于基于季节设定的阈值（1000至3000）。由于云覆盖影响，多数像元每年均无法被有效观测，因此该数据仅代表最大可能植被年龄（实际植被年龄可能更小）。该图层的相关信息已应用于PVCTS地图中，但反之则不成立（即仅基于NBR阈值进行判定，未纳入其他额外数据）。"metadata_spatial_ss"为所有GeoTiff文件提供空间元数据，投影坐标系为WGS_1984_UTM_Zone_17N。