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 maps in the figure were produced in ArcGIS 10.8 (ESRI, Redlands, CA, USA) using shape files representing Xi’an City which were obtained from the basic geographic database in National Catalogue Service For Geographic Information of China (https://www.webmap.cn/mapDataAction.do?method=forw&resType=5&storeId=2).
