Applied Landsat-5 TM and Vector Data through Computerized Techniques in Developing Forest Maps and Forest Cover Maps at Thung- Saliam District, Sukhothai Province, Thailand
Manasanan kantontong
Geographician (cartographer )
Forest Resource Analysis Division, forest Research Office
Royal Forest Department, Bankok 10900,
Thailand .
Abstract
A study on the classification of forest types, landuse patterns and human activities was conducted at Thung- saliam District, Sukhotai province in northern Thailand. The purpose of the study is to produce a forest map, a forest cover map and a 3-dimensioal view (3-D perspective view ) of the forest cover of Thung-Saliam District by using Landsat5-TM imagery (FCC) and the computer compatible tap (CCT. Tape ) containing Lansat 5-TM data. By using a CCT. Tape, data interpreted from Landsat 5-TM imagery and visual interpretation, data collected from the study area were processed and analyzed by the special program naming EASI/ PACE version 6.2.2 incorporated with SOLARIS 3.5.1 operating system. The method applied in the study is based on a supervised and an unsupervised system of Maximum Likelihood Algorithm and overlay analytical techniques which were employed to solve conditions as required. The final outcome indicated that using the supervised together with the unsupervised systems would give one specific best result apparently identifying the Landsat -5 TM data into 8 categories: water body, paddy field, cropland, heterogeneous orchard with natural stand, completely destroyed mixed with degraded forest, dry dipterocarps forest, mixed deciduous forest and other areas. The result after overlaying a forest cover map on the DEM was a 3-D perspective view of forest cover information of Thung-Saliam District. The forest cover map and 3-D perspective view techniques.
Introduction
Thailand has been endowed with rich forest resources. In 1950 s, over half of the entire kingdom has been covered with forests of heterogeneous types. Timbers and non-forest produces were superfluous. Timbers were among the principal natural resources of exporting commodities which earned great amount of incomes annually and the played a significant role in developing this country of many decades . unfortunately, these natural resources have been exploited and depleted rapidly in the last few decades particularly forest. Due to population pressure associated with rapid expansion of agricultural lands, forest areas decreased down drastically . extensive pieces of forest lands have been cleared and converted into crop fields and other used. Some forest parts of the country with moderate slope have been disturbed beyond recognition: big forest have been fragment in to small patches scattering all over the country. This destructive human activity continued uninterrupted annually. Forest covers decreased down to merely 25% of country area nowadays.
In order to monitor an catch up with the forest area changing new forest survey and mapping technology viz., Landsat imagery technology has been introduced into the service of the Royal Forest Department (RFD) to substitute the out of date ground survey in 1973. data from various satellite have been obtained via the Natural Research Council of Thailand which has data receiving station of its own.
Nevertheless, mapping surveying technology of natural resources including forests have been developed rapidly in the last few decades and computerized technique is very effective, reliable, and expeditious at present. As mentioned earlier, to catch up with the ever-changing of forest areas of the country the computerized techniques ie., sun Ultra-1 workstation with soft wares EASI/PACE (version 6.2.2) has been used by the RFD in 1988. data obtained from some existing satellites such as Landsat MSS, Landsat TM, spot, Mos-1 and JERS-1 can be obtained expeditiously through this programme. Many information can be obtained expeditiously through this programme. In order to familiarize with this technique, application of newly introduced forest mapping has been done at Thung- Saliam district in Sukhothai province .
Objective
This study has the following objectives.
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Assessing the existing forest lands in study areas, 1.e, Thung- Saliam district by district by using Landsat-5 TM imagery, CCT. Tape accompanied with ground check.
- studying vegetation distribution , forest type, and human disturbance in study area.
- evaluating the limitation of the Landsat -TM imagery (FCC) and Landsat 5-TM digital data (CCT. tape ) in identifying the existing forests, forest types disturbed areas etc.
- try out the functional feasibility and effects of the sun Ultra-1 workstation with operating system spares 3.3.1 and software EASI/PACE package version 6.2. for forest classification and overlay analytical techniques for the following purpose.
- identifying and differentiating forest covers, forest types, level of disturbances
- generating the digital Elevalion Model (DEM) and 3-D perspective view of study area and
- installing raw and classified data in the database.
