Terrestrial Lidar

Terrestrial lidars have characteristics such as:

They have many uses, including

Terrestrial lidar points clouds have gaps from occluded terrain, which were not sampled by another scan.

Many terrestrial scans use local coordinates, or EPSG code 4978.   EPSG 4978 is a geocentric XYZ coordinate system, which is not particuarly GIS-friendly, and there can be challenges in transforming this data into a usable projection.

The laser scanner sits on a tripod, and scans in a circle around the instrument.  It also moves up and down, but cannot view directly below the instrument, and there will be circle around the instrument with no coverage unless another scan images the area.

This survey probably has 10 survey locations.

Multiple scans can be merged using the GPS coordinates of each scan, or by using reflectors with know coordintes appearing in several scans.
Scans will capture people and and vehicles and the same objects can appear in multiple scans and hence multiple times in the merged point cloud.

The people where only captured by a single scan, and are pancakes, as is shows by the second person from the left.

last revision 12/21/2017