Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The risk groups are color-coded, with RG 4 (highest risk) as red and RG 1 (lowest risk) in light yellow. The figure was created using R software with base layer obtained from https://landsatlook.usgs.gov/.
