proj4.defs("EPSG:8031","+proj=tmerc +lat_0=0 +lon_0=115.816666666667 +k=0.99999906 +x_0=50000 +y_0=3900000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs");