Field data collection is a problem that has long plagued surveyors, cartographers, GIS database managers, engineers, and researchers. The problem is simple: how to efficiently and accurately collect location and physical characterization data for mapping, cataloguing, inventory and storage in databases.
Finding the outcome of this problem in a given situation is vexing. because:
(1) There may be many methods and techniques that can be used;
(2) In the vast majority of cases, no single method alone provides complete and satisfactory results.
The application of laser technology, especially the laser rangefinder developed by American Laser Technology Corporation (LTI), has been perfected day by day since it was used by the USDA Forest Service as a field measurement prototype in 1990 to evaluate its future development and application, and can be combined with data acquisition. Instruments, GPS connections, and a variety of configurable software enable forestry surveying to advance from hand-operated compasses, rope straps, inclinometers, and old-fashioned telescopes to the era of one-man, full-station, fully-integrated multi-purpose instruments.
The measurement system designed by LTI is suitable for the inspection and planning measurement of basic vegetation resources and timber sales, the distribution map of logging volume and road survey measurement. As of June 1993, the US Forest Service had purchased more than 150 of these instruments. In the field planning and use of the USDA Forest Service, the laser rangefinder is not only fully functional, accurate and durable, but also cost-effective, especially where the target is unclear. From the scrublands of northern Idaho to the great rainforests of southeastern Alaska, it's attested.
The country with vast resources is rich in forestry resources. With the large-scale production brought about by the reform and opening up, the important position of forestry in the national economy has become increasingly prominent, and the demand for commercial timber has surged. How to plan the development of forestry, more accurate measurement of forestry resources, and more accurate inventory and cataloguing of forestry resources focusing on timber sales have become important issues in the forestry sector. Our introduction of laser measurement technology will help to promote my country's forestry measurement technology into a new era.
Discussion on the application of multifunctional laser measuring system in forestry
(1) Woodland measurement
Because the multi-functional laser measuring system combines laser ranging and electromagnetic digital compass, its ranging and angle measuring accuracy is much higher than that of compass and measuring rope.
According to the test, the advantages of the multi-function laser measuring instrument used in forest land measurement are:
1) The operation is simple, the measurement is locked very quickly, and the precision is high. The instrument can automatically record the data and transmit it to the computer without human error.
2) The digital instrument panel is automatically displayed, and there is no human visual interpretation error.
3) Save manpower and time. 4
) With processing software, it can do point, line, wire processing and calculation of closure difference, area, etc., and can be connected to a printer or plotter to directly draw measurement graphics.
(2) Combination of multi-function laser measuring instrument and GPS
The introduction of the multi-function laser measuring instrument was mainly combined with GPS at the beginning, that is, GPS cooperated with the multi-function laser measuring instrument to measure in the terrain-restricted areas.
application:
1) Banning and Investigating Excessive Land Reclamation
The use of laser measuring instruments combined with GPS, GIS and their software, and portable computers to carry out environmental monitoring is currently a popular research project in various academic institutions. In forestry, it is the application of banning and inventorying overland reclamation. However, because GPS may be limited by terrain, further research and testing are needed. In addition, it can also be combined with a digital camera to photograph and archive the violations for evidence of banning.
2) Check the leased land
The multi-function laser measuring instrument and GPS are combined to carry out the inspection of leased land, which is not only fast, but also has high accuracy. In addition, the digital image files can also be pre-entered into a portable computer and brought to the site for inventory and comparison work.
3) Inventory of security guards outside the district
At present, the inspection of security forests outside the area of this bureau is carried out by electronic flat panel instruments for inspection and pile placement. However, due to insufficient triangular points, the inventory work is often slow. If the public grade GPS can be used to lay out the points, then the laser measuring instrument can be used to conduct the survey, and the target coordinate program function can be used to carry out the pile placement work, which should speed up the inventory work and reduce the post-event map dataization work.
Compared with the traditional compass, the multi-function laser measuring instrument has the advantages of high precision, no recording, no drawing, no pulling measuring rope, no cutting grass, saving time and labor, and computer processing and drawing. There are many more, and it is worth promoting the pulsed laser rangefinders for tactical and strategic use, mainly including pulsed laser rangefinders such as ruby, Nd:YAG, CO2, Raman frequency-shifted Nd:YAG and Er:glass.
