Content area
Full text
INTRODUCTION
Without accurate geographical (survey) information no construction project can proceed, AU professionals need reliable data for planning, design, execution and as-built purposes.
Historically the surveyor supplied this data by:
* Ground survey with conventional equipment
* Aerial survey methods
During the past few years the construction industry was introduced to:
* Airborne LIDAR mapping
* Terrestrial (ground-based) LIDAR mapping
The latest development, however, is high-resolution 3D mobile mapping.
DEFINITION OF LIDAR
LIDAR stands for Light Detection And Ranging. It is a threedimensional laser scan and each pixel that is scanned is assigned an x, y and z value which allows for accurate 3D mapping.
WHAT IS 3D MOBILE MAPPING?
A three-dimensional mobile scanning unit comprises laser sensors, navigation sensors (IMU) and high resolution cameras. The unit captures millions of points and each point is assigned an x, y and z value. From this data a point cloud is generated that is transformed into a 3D image. Data can be extracted automatically or manually and the software has unique object recognition abilities to identify objects such as road signs, markers, etc.
ADVANTAGES OF 3D MOBILE MAPPING
The great advantages of mobile mapping are:
* Survey grade accuracy under very challenging conditions.
* Extremely fast - one can map to 1 cm accuracy at speeds of 70 km per hour.
* Safe - one gets one's surveyors out of danger areas such as busy...