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.
Data are sometimes delivered with many decimal places--far beyond the number of significant digits. This requirement will specify the maximum number of decimal places to be used for linear data. This requirement does not apply to non-linear geographic coordinates.