FAQ - GPW: Why are there negative numbers in the Population Density files(GPW V4.11)?
Posted: Thu Aug 15, 2024 3:33 pm America/New_York
The negative values are how the "no data" pixels are stored (mostly ocean/water), these can be set to zero or NaN (not a number). This information is stored in the TIF file header (in the ASCII version the no data value is -9999).