Laboratory;
for;
Urban;
Geomatics;
of;
National;
Administration;
of;
Surveying,;
Mapping;
and;
Geoinformation;
BeijingUniversity;
of;
Civil;
Engineering;
and;
Architecture,;
Beijing;
100044,;
China;
Of;
Geoscience;
and;
Surveying;
Engineering;
China;
University;
of;
Mining;
&;
Technology,;
Beijing;
100083,;
China;