Use of high resolution Remote
Sensing data for land use investigation in Vietnam Pham Trung Luong, Truong
Thi Hoa Binh Remote sensing Application Division Center of Geography and Natural Resources NCSR of Vietnam Introduction The use of remote sensing data as Landsat 1, 2, 3 for study and investigation of Landuse in Vietnam has been carried out since 1980 and has given good results that permit to overcome and disadvantages of traditional method. However, in many cases, due to Laduse characteristics of developing country likes Vietnam and different Landuse traditions of different geographic regions, a more detailed investigation and classification on higher level are demanded for: - statistic work; study of destruction of agricultural land and natural forest under natural and human actions detection of changes of Landuse, crops and irrigation; - investigation of reclaiming waste land and forest replantation. In those cases, Landsat 1,2,3 images are not satisfied and high-resolution data likes Landsat 4 TM and SPOT images are required. They permit to revolutionize Landuse investigation using remote sensing technology. These will be discussed in this paper with results of some experiments using available data. High Resolution Remote Sensing data analysis for landuse investigation Landsat 4 TM images are not available in Vietnam that is why only SPOT images are used as high-resolution data for more detailed land use investigation of different geographic regions of the country. Spectral resolution of SPOT are three spectral bands 9visble and near infrared portions of the spectrum) with 20m of ground resolution and a broader spectral band (Panchromatic B and W) with 10m of ground resolution. In order to study landuse patterns based on remote sensing techniques, three bands in visible and near IR part of the spectrum are mainly used. The first one is the green (First maximum of the reflectance) the second one is the red (minimum of the reflectance due to Chlorophyll absorption) and the third is near IR where the reflectance of active vegetation for Landsat MSS: Band 4,5 and 7 for Landsat TM: bands 2,3, and 4 and for SPOT bands 1,2 and 3. Usually above bands combinations have been shown by color composite on which the first band is printed in blue, the second - in green and third - in red. Available SPOT data here does not ever entire Vietnam. There are only some POST image of regions (Mekong river delta, Northeastern part of Red river delta and central plateau (Scheme 1). Used data for this study are the followings.
Information ability of Landsat MSS and SPOT images for
land use investigation of mekong river delta Table. 1
Another region is Daklak province, which has high potential of forest, coffee, tea and rubber plantation. People in this province, is minor, nations mainly. Their tradition sis shifting cultivation. They cut the forest, grow the corps and after harvest they abandon the used lands, which became waste, and go to other place and being to cut the forest and etc…. again. due to above mentioned cause, landuse changes very quick. This change can be detected on SPOT image. Interpretation result of SPOT images is shown in table 2. On SPOT FCC (of bands 1, 2 and 3) landuse patterns are seen in various of yellow orange and red tone and we can classify landuse patterns in detail and we can study and monitor deforestation and reforestation. Information Ability of Landsat MSS and spot images for
Landuse investigation of centeral plateau Table 2
Conclusion Using high-resolution Remote Sensing data ahs more advantages than MSS data. That kind of a data can satisfy the practical demands of land use investigation in Vietnam at present. For landuse investigation and its planning on sub district level (at scales 1:100,000 and 1:50,000) use of high resolution remote sensing data has economic effect. Use of the high resolution remote sensing data combined with other data likes aerial photos or ground data permit to investigate landuse upto scale 1/25,000. References
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