Application and analysis on forest types and land-used classification using digital image processing
Manasanan Kantontong
Geographician (Cartographer)
Office of Remote Sensing
Survey and Mapping
Royal Forest Department
Bangkok, Thailand
Abstract
A study on the classification of forest types, natural vegetation distribution, land-used patterns and other artificial activities made be man was conducted at Lamphun province in northern Thailand. The purpose of the study is to make the forest land cover map, by using computer compatible tape containing Landsat-5TM data. The study areas were classified by digital image processing using Compaq Despro 386/20 and later classified by program EASI/PACE veriosn 4.2. Out of 7 bands, only 3, i.e., : band 2, band 3 and band 4 were obtained form Landsat – 5TM and interpreted data. The method applied in this study is based on the supervised and unsupervised system of Maximum Likelihood Agorithm. The result indicated that the supervised system offers a favorable result when combining with the unsupervised system. The final results clearly separates the Landsat – 5TM data into 10 categories, as follows: water, paddy field, croplands, orchard, dry dipterocarp forest, mixed deciduous forest land, evergreen forest, rock pan tree, and other types of areas. The study showed that using supervised together with unsupervised system provided better result and a possible application to other relevant uses of forest land classification.
1. Introduction
Landsat Imagery In Forestry
In 1973, after the Royal Forest Department (RFD) has already been a member of the National Research Council, Thailand, the data from satellite imageries, indirect visual interpretation for forest type map, existing forest map, and watershed map, etc., were brought in for forestry resources survey. Since 1983, scientific and survey technique concerning natural resources was developed. RFD has brought in computerized technique “Compaq Despro 386/20” with software EASI/PACE version 4.2 for the use of interpretation and analysis, for example, Landsat MSS, Landsat TM, spot and MOS-1. The data from satellite imageries indicate not only the changes in the forest recourses but also provide the data for solving problems and planning forest resources in the future.
2. Objectives
- To assess forest land in Lamhun province by using Landsat -5TM data and CCT-tape ( computer Compatible Tape) in combination ground truth interpretation for beneficial application on forestry management by RFD.
- To study vegetation distribution, forest types, and artificial activities made by man in Lamphun province.
- To study the limitation of the Landsat-5TM data ( False Composite Image ) and Landsat-5TM digital data ( CCT. tape) utilization on survey of forest types and other areas.
- To study the functional feasibilities and efficiency of Compaq despro 386/20 with software EASI/PACE package version 4.2 which consists of a lot of programs in classifying forest resources, other agricultural crops, and artificial activities made by man.
3. Study Area
3.1 Area Selected
Lamphun, a northern province of Thailand, is situated between the latitude 17’ 25’ – 48’45’ and the longitude 98’ 40]. It includes approximately 4,505 square kilometers. Lamphun’s boundary is far from the sea; the characteristics of the climate is the ever-changing monsoon climate and is very hot in the hot season. her climate is mainly influenced by the south-west and north-east monsoons. There are, in addition, typhoon, cyclones and depressions. Due to the regular monsoon through the year, the province has three alternating seasons, namely, the rainy season, the cold season and the dry season.
3.2 Statistical Data
Rainfall and average temperature from the past 10 years ( 1980-1990 ) of Lamphun province were given from the Meteorological Department, Ministry of Prime Minister and introduced to match with the Gaussen’s theory. The formula of the dry period p<2T were brought to analyze the combination between rainfall and temperature and he distribution of rainfall per year in Lamphun province.
p<2T
p= the amount of the annual rainfall in average
T= the mean temperature of the coldest month
Owing to this formula, it is found that Lamphun’s average volume of rainfalls in 1980-1990 is 980.7 mm. and the average temperature is 26.1 c. The most rainfall, 190.2 mm, is in September. December is the coldest month of which temperature is averagely 20.8 c.; whereas the hottest temperature is 30’c. in April.
The volume of rainfall and the temperature affect greatly on natural vegetation in Lamphun province. Accordingly, water performs a process of weathering, erosion and development of vegetation, and temperature effects generally seed budding, plant growing and spreading of plant roots.
4. Sources of Data
- topographic map at scale 1: 250,000.
- Landsat-5TM data, scale 1:250,000 / False Color Composite Image (FCC image) were taken from satellite image obtained by Landsat-5TM on April, 3 1990: ( path 131 row 47) and ( path 131 row 48) were also used as the ground truth information.
- Computer compatible Tape (CCT. Tape) of Landsat-5TM was obtained from the receiving station of Thailand in BIL ( Band Interleaved by Line ) format, 9 tracks, 2,400 ft. of length and 6,250 BPI intensity.
- PC. Hardware: Compaq “Despro 386/20” with software EASI/PACE of the PCI, Canada, version 4.2.
- The field data ( ground truth data ) were gathered by using the method of random sampling.
