Spatial resolution : 30m (0.000269494585235856472 degree)
CRS : EPSG:4326
Format : GeoTiff

The global data was stored in 921 tiles (5° by 5°) with file name originzed as fellow:
GISA_v01_1972_2019_*N_*E.tif
where * indicates the latitude and longitude of the upper left corner of the tile.

Pixel values in each map indicate the first year when ISA was detected. No-data was labeled as 0. 
A look-up table for the detected year and pixel value is provided as follow: 
year of first ISA:[1972, 1978, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019]
pixel vaule[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37]

Citation: 
Huang X, Li J, Yang J, Zhang Z, Li D, Liu X. 2021. 30 m global impervious surface area dynamics and urban expansion pattern observed by Landsat satellites: from 1972 to 2019. Science China Earth Sciences, 64, https://doi.org/10.1007/s11430-020-9797-9
黄昕, 李家艺, 杨杰, 张震, 李冬瑞, 刘小平, Landsat卫星观测下的30m全球不透水面年度动态与城市扩张模式(1972~2019), 中国科学：地球科学,  ISSN 1674-7240, https://doi.org/10.1360/N072020-0370.