The laser rangefinder uses laser to measure accurately and can cross obstacles, and the ultrasonic measurer uses sound wave measurement. Ultrasound propagates conically from the instrument and only gives inaccurate measurements. In addition, objects and pillars can also cause sound waves to be deflected. Usually the working distance of ultrasonic measuring instrument is 20 meters, while the working distance of laser measuring instrument can reach 200 meters, and the measurement effect is still more accurate! Field data collection is surveyor, cartographer, GIS database processor, engineer and researcher long-term problems of personnel. The problem with laser rangefinders is simple: how to efficiently and accurately collect positioning and physical feature data for mapping, cataloging, resource inventory, and database storage.

Figuring out what the problem does in a given situation is troublesome. because:

(1) There are many methods and technologies that can be used;

(2) In the vast majority of cases, there is no single way to provide satisfactory functionality.

Data collection is used for inventory of forestry resources, that is, tree height, height that can be used for commercial timber, vegetation manufacturing, location of wild exception tree species and excellent tree species, to judge the grade and economic value of trees in the area, or to prune and other cultivation treatments and discussions When considering the baling method in wood harvesting, measure and make the terrain of the road used for baling wood, and inquire about general-purpose roads and construction The front bump path is very important. Various issues (such as cost, accuracy, obstacles, etc.) can be encountered through the use of conventional inquiries, aerial photography, and GPS positioning.

The application of laser technology, particularly the laser rangefinder developed by US companies, has been refined since 1990 by the USDA Forest Service as a prototype for field measurements and for future evaluation. It can be connected to a data collector and GPS, and can be equipped with a variety of rich software, enabling forestry surveying to move from a manual compass, rope, inclinometer and old telescope to the era of single-person, total-station, all-purpose multi-purpose instruments.