Monitoring of Land use Changes
4.0 Data Source Used
The following available data have been used in the analysis.
| Data |
Data |
Scale /Resolution |
| IRS LISS -II |
March 1992 |
40m |
| Land Use Maps of Ampra & Moneragala |
Aerial Photographs used in 1981-1984 |
1:100,000 |
| Topographic Map of Panama |
1987 |
1:50,000 |
5.0 Methodology
The outline of the general methodology is shown follows.
Figure 2.0
IRS-LISS II digital data used here is geocoded and radiometrically adjusted but was not colour enhanced. Spatial Resolution of IRS data is about 40m in pixel size.
Geometric Correction have been applied to georeference the raw image using the map. Linear enhancement technique with 2,3,4 band combination is used in this analysis. Enhanced the image using linear stretch based on the histogram and it has been transformed. Look up table was used to enhance 8 bit image data without actually modifying it by altering (remapping) image grey level before they are shown on the monitor. Enhancement serve to improve the contrast.
Land Use map of the study area was digitized using PC ARC /INFO. Then vector data was converted to raster format in order to use it with PCI software for further processing. See Fig. 2.0 Then it has been used to georeference the image.
Supervised classification was used in this analysis. First we selected the training sites and visually digitized it. The selection of training areas was based on spectral signature and spectral separability among classes. These training samples were used in the maximum likelihood classification. However, the result were not much discriminate landuse patterns when comparing it with prior information. It may be the similar spectral reflectance of landuse pattern in the study area.
Therefore, landuse pattern identification was performed by visual interpretation of the enhanced initial data. The visually interpreted landuse boundaries had been converted to vector format. The land use boundaries have to spline before overlaying it was existing landuse layer.
6.0 Results and conclusion
the study of Panama area was based on the analysis of satellite data. It shows the potential of detecting changes. Because of its high spatial resolution it was found to be quite helpful in extracting the requisite information for mapping land use/land cover.
A wide range of Land use/land cover categories and features like water bodies, river & lagoons, sand rocks, scrub land, built up area was identified through the semi automatic analysis of the satellite data. Based on the analysis land use changes can be detected comparing land use map.
If multitemporal data with high spectral and spatial resolution is available the better results can be obtained.
References
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PCI software, version 6.0 EASI/PACE, January 1, 1996, Volume I.
