Data collection for forest resources inventory, namely, tree height, can make the height of the commercial timber, vegetation, wild special tree species, tree species, confirm the area level and the economic value of trees, or when making training management discussion such as pruning, decided to highly specific local tree bearing, production volume profile cut wood, confirm the resource boundary;When considering the method of bundling, it is very important to determine and make the topography of the bundling wood passageway, as well as inquire before the construction of the road and the rugged path for general purpose.Using the usual practices of searching, aerial photography, and GPS positioning may encounter various problems (e.g., cost, accuracy, obstacles, etc.).
Outdoor data collection has long been a problem for surveyors, cartographers, GIS database managers, engineers and researchers.The problem is simple: how to efficiently and accurately collect location and physical feature data for mapping, cataloging, resource inventory, and database storage.
In a given situation, the results of identifying this problem are disturbing.Due to:
(1) there may be many ways and skills to use;
(2) in the vast majority of cases, there is no single way to provide good and satisfactory results.
The use of laser skills, particularly in the us company research and development of laser rangefinder since 1990 by the United States department of agriculture forestry administration as outdoor measurement prototype since its use, and to evaluate its future improvement, and can interface with data collection, GPS, rich in a variety of software and equipment, the forestry measurement by hand a compass, rope, skew and old telescope to a single operation, total station, comprehensive multi-purpose instrument era.
The measurement system designed is suitable for the basic vegetation resources and timber sales inspection and planning measurement, timber cutting distribution map and road query measurement and so on.By June 1993, the United States forest service had purchased more than 150 of these instruments.For outdoor planning in the usda forest service, the laser rangefinder is not only functional, accurate and durable, but also cost effective, especially in areas where guidelines are unclear.From the bush lands of northern Idaho to the great rain forests of southeast Alaska.
Our country with vast resources has abundant forestry resources.With the large-scale production brought by the reform and opening up, forestry plays an increasingly significant role in the national economy, and the demand for commercial timber surges.How to plan the development of forestry, the measurement of forestry resources with higher precision, and the more accurate inventory and cataloguing of forestry resources with timber sales as the key points have become important issues for forestry departments.Let's introduce laser measurement skills, will help to promote the forestry measurement skills of our country into a new era.
USES of Multi - function laser measurement system
(I) interval measurement -- interval measurement is the main function of this instrument, which can directly show horizontal interval or skew interval.
(2) azimuth -- can directly display the magnetic azimuth of the measurement policy, perhaps relative azimuth.
(3) skew Angle -- can show the skew point of view (vertical Angle) or skew percentage.
(4) policy coordinate program -- the function of policy program is the function of so-called addressing or piling (lofting) in measurement, that is, input its coordinates (X, Y, Z) into the instrument at known points to align with the coordinates that can be immediately displayed in measurement of policy.
(5) height measurement -- use the trigonometry principle (elevation Angle, elevation Angle and horizontal interval) to measure the height of objects, including the height of trees and buildings.
(6) measurement function -- this instrument has another special function program, which can directly enter the measurement function, carry out measurement and actively store the azimuth Angle, spacing, skew Angle and other materials, and can be input into the computer, after accounting by PC software.
(7) navigation function -- because of the magnetic flux compass, can serve as a navigation function.
Discussion on the application of multi - function laser measurement system in forestry
Due to the multi-function laser measurement system combined with laser ranging and electromagnetic digital compass, its ranging and measuring Angle accuracy is much higher than that of compass instrument and measuring rope, which is actually the best new measuring instrument for woodland.
According to the test, the advantages of the multi-function laser measurement instrument used in forest measurement are:
1. Simple operation, fast measurement and high precision.The instrument can actively record data, computer transmission, no human error.
2. The digital dashboard shows itself actively, and no human visual interpretation error is found.
Save time and manpower.
4. With processing software, it can do the processing of points, lines and wires, and calculate the closure error and area, etc., and connect the printer or plotter to draw the measurement graph directly.
(B) Multi - function laser measurement instrument and GPS combined
1. Land reclamation cancellation and inventory
Combining laser measurement with GPS, GIS and its software, and cooperating with portable computers for environmental monitoring is the most popular research project of academic organizations at present.In forestry, it is to use land reclamation and inventory, but due to the use of GPS may be restricted by topography, it is still necessary to further study and test.In addition, it can also be combined with digital cameras to take photos of violations and archive them for revocation.
2. External security forest inventory
At present, the bureau outside the district security forest inventory, the use of electronic board for inventory and piling operations.However, due to the lack of triangular points, often resulting in slow inventory operations.If the cm-level GPS can be used to arrange the points, and then the laser measuring instrument can be used for measurement, and the policy coordinate program can be used for pile laying, the inventory operation can be accelerated and the data mapping operation can be reduced afterwards.
3. Land rental inventory
Multi-function laser measurement instrument and GPS combined with land rental inventory operations, not only fast, but also high accuracy.In addition, digital image files can be pre-input into a portable computer and carried to the site for inventory and comparison.