Fig. 1

The distribution by place of the human immunodeficiency virus (HIV) in Nanning during different periods. The signal of the red point represents the site of Nanning city in China. Colors represent local HIV prevalence. Blue represents low HIV prevalence, whereas red represents high HIV prevalence. The shapefile for China was downloaded from the standard map service (http://bzdt.ch.mnr.gov.cn/) (drawing review no. Das, Li, Allston, and Kharfen [12] 1822), from which the Nanning shapefile was extracted using ArcGIS