Imperviousness Change 2012-2015 (raster 20 m), Europe, 3-yearly, Apr. 2018

The high resolution imperviousness products capture the percentage and change of soil sealing. Built-up areas are characterized by the substitution of the original (semi-) natural land cover or water surface with an artificial, often impervious cover. These artificial surfaces are usually maintained over long periods of time. A series of high resolution imperviousness datasets (for the 2006, 2009, 2012, 2015 and 2018 reference years) with all artificially sealed areas was produced using automatic derivation based on calibrated Normalized Difference Vegetation Index (NDVI). This series of imperviousness layers constitutes the main status layers. They are per-pixel estimates of impermeable cover of soil (soil sealing) and are mapped as the degree of imperviousness (0-100%). Imperviousness change layers were produced as a difference between the reference years (2006-2009, 2009-2012, 2012-2015, 2015-2018 and additionally 2006-2012, to fully match the CORINE Land Cover production cycle) and are presented 1) as degree of imperviousness change (-100% -- +100%), in 20m and 100m pixel size, and 2) a classified (categorical) 20m change product.

高分辨率不透水性产品可捕捉土壤密封的百分比及其变化。建成区的特征是原始（半）自然地表或水面被人工（通常为不透水）覆盖所替代，这些人工表面通常长期维持不变。基于校准的归一化植被指数（Normalized Difference Vegetation Index，NDVI），通过自动推导生成了一系列覆盖所有人工密封区域的高分辨率不透水性数据集（参考年份为2006、2009、2012、2015和2018年）。这一系列不透水性图层构成了主要的状态图层，它们是对土壤不透水覆盖（土壤密封）的逐像素估算，并以不透水度（0-100%）的形式进行映射。不透水性变化图层通过计算参考年份之间的差异生成（包括2006-2009年、2009-2012年、2012-2015年、2015-2018年，此外为完全匹配科林土地覆盖（CORINE Land Cover）的生产周期，还包括2006-2012年），并以两种形式呈现：1）不透水度变化（-100%至+100%），像素大小为20米和100米；2）分类（类别型）的20米变化产品。