Key;
Laboratory;
of;
Resource;
Survey;
and;
Research;
of;
Hebei;
Province,;
Hebei;
Universil3,;
of;
Engineering;
Handan,;
Hebei;
056038,;
China;
The;
Bureau;
of;
Land;
and;
Resources;
of;
Wu'an;
City,;
Wu;
'an,;
Hebei;
056300,;
China;