Materials and Methods
1.1.2. Earth Observation Data:
LISS III Image: The image was taken on 02 February 2004. It has four bands red, green, blue and near infra red. The red, green and near infra red bands are of 23.5 m resolution.
| Sensor | LISS III |
|---|
| Resolution | 23.5 m |
| Swath | 127 Km (Bands 2, 3, 4)
134 Km (Band 5, MIR) |
| Repetivity | 25 days |
| Spectral Bands | 0.52 - 059 microns (B2)
0.62 - 0.68 microns (B3)
0.77 - 0.86 microns(B4)
1.55 - 1.7 microns (B5) |
Table 3: Nominal Characteristics of Aster Image
LANDSAT-7 ETM+ Image: The image was taken on December 2001. It includes spectral regions of VNIR (bands 1-4 with 30 m resolution), SWIR (bands 5 and 7 with 30 m resolution and TIR (band 6, with 60 m resolution) and one panchromatic band 8 with 15 m resolutions. The Enhanced Thematic Mapper Plus (ETM+) is the instrument payload on the LANDSAT-7 spacecraft. The ETM+ is a derivative of the Thematic Mapper (TM) instrument on LANDSAT-4 and LANDSAT-5 (Markham, 2003).
| Band No. | Band-pass (μm) | Spatial Resolution (m) |
|---|
| 1 | 0.452-0.514 | 30 |
| 2 | 0.519-0.601 | 30 |
| 3 | 0.631-0.692 | 30 |
| 4 | 0.772-0.898 | 30 |
| 5 | 1.547-1.748 | 30 |
| 6 | 10.3112.36 | 120 |
| 7 | 2.065-2.364 | 30 |
| 8 (Pan) | 0.515-0.896 | 15 |
Table 4: Overview of the nominal characteristics of Landsat-ETM+
ASTER Image: The image was taken on June 2004. The Advanced Based Thermal Emission and Reflection Radiometer (ASTER) sensor is an imaging instrument flown on the Terra Satellite which was launched in December 1999. An ASTER scene covers an area of approximately 60 Km x 60 Km and the data is acquired simultaneously at three resolutions. An ASTER scene consists of 14 bands of data with one additional band pointing backwards to create a parallax. The three bands of visible and near infra red part of the spectrum have a 15 m resolution and an 8 bit unsigned integer data type. The six bands in the short wave have a 30 m resolution and also have an 8 bit unsigned integer data type. There are 5 thermal bands with 90 m resolution and have a 16 bit unsigned integer data type.
| Band | Label | Wavelength | Resolution |
|---|
| B1 | VNIR_Band1 | 0.52-0.60 | 15 m |
| B2 | VNIR_Band2 | 0.63-0.69 | 15 m |
| B3 | VNIR_Band3 | 0.76-0.86 | 15 m(Nadir View) |
| B4 | VNIR_Band3 | 0.76-0.86 | 15 m (Backward Scan) |
| B5 | SWIR_Band4 | 1.60-1.70 | 30 m |
| B6 | SWIR_Band5 | 2.145-2.185 | 30 m |
| B7 | SWIR_Band6 | 2.185-2.225 | 30 m |
| B8 | SWIR_Band7 | 2.235-2.285 | 30 m |
| B9 | SWIR_Band8 | 2.295-2.365 | 30 m |
| B10 | SWIR_Band9 | 2.36-2.43 | 30 m |
| B11 | TIR_Band10 | 8.125-8.475 | 90 m |
| B12 | TIR_Band11 | 8.475-8.825 | 90 m |
| B13 | TIR_Band12 | 8.925-9.275 | 90 m |
| B14 | TIR_Band13 | 10.25-10.95 | 90 m |
| B15 | TIR_Band14 | 10.95-11.65 | 90 m |
Table 5: Nominal Characteristics of Aster Image
MODIS/Terra Surface Reflectance 8-Day L3 Global 250m SIN Grid V004 (MOD09Q1)
The surface reflectance product is the input for product generation for several of the land products: Vegetation Indices (VIs), BRDF, Thermal Anomalies, Land cover, Snow/Ice Cover, and LAI/Fpar. It is an estimate of the surface spectral reflectance for each band as it would have been measured at ground level if there were no atmospheric scattering or absorption. This product is a composite using eight consecutive daily 250 m images. The “best” observation during each eight day period, for every cell in the image, is retained. This helps reduce or eliminate clouds from a scene. The file contains the same spectral information as the daily file listed above, centred at 645 nm and 858 nm. There is one additional band of data for quality control. It has three layers and the layer1 and 2 has been used for NDVI computation. The surface reflectance (MOD09Q1) and NDVI derived from surface reflectance image shown was retrieved from MODIS data during April, June and August from 2000 to 2005 over Sonitpur district of Assam, India.