(1) The spatial resolution is 30m.

(2) 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. Image id and location can also be found in this shape file.

(3) The value in the map ranges from 0 to 37, indicating different years. Zero means non-impervious, values greater than zeros indicate impervious pixels. Year and pixel value pairs are as following: [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]-> [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]

(1) 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.

(2) 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.

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

The global data was stored in 5° by 5° tiles with file name originzed as fellow:
GISA_v02_1972_2019_*N_*E.tif
where * indicates the latitude and longitude of the upper left corner of the tile. Image id and location can also be found in this shape file.

Pixel values in each map indicate the first year when ISA was detected. Non-ISA 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]

(1) Huang, X., Song, Y., Yang, J., Wang, W., Ren, H., Dong, M., Feng, Y., Yin, H., & Li, J. (2022). Toward accurate mapping of 30-m time-series global impervious surface area (GISA). International Journal of Applied Earth Observation and Geoinformation, 109, 102787, https://doi.org/10.1016/j.jag.2022.102787.

(2) 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.

(3) 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.