The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
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Land cover category 
Physical characteristics 
Interpretation keys 
Land 
cover 
code 
Level 1 
Level 2 
Forest 
Forest 
• Tropical wet evergreen and semi 
evergreen forest 
• Light cyan 
• Medium texture 
• Irregular boundary 
• Located in the hilly terrain and 
topographic features are visible on 
the radar image 
1 
Plantation 
• Planted with various species 
(Dipterocarpus turbinatus, 
Syszygium grande, Artocarpus 
chaplasha etc.) 
• Light cyan 
• Smooth texture 
• Ground information is sometimes 
necessary to separate this class from 
forest 
2 
Non-forest 
vegetation 
Mosaic 
• Formed after removal of forest 
• Mixture of dark red and light cyan 
3 
Shrubs 
• Scrubby vegetation intermixed with 
grasses, seedlings and saplings of 
trees and bamboos 
• Dark red 
• Scattered occurrence of white 
colour is sometimes noticed 
• Terrain features are often vivid 
4 
Agricultural 
crops/Rural 
homesteads 
with tree 
coverage 
• Paddy and other annual or perennial 
crops 
• Homestead with tree coverage 
• White 
• Usually located in the plain-lands 
• Terrain feature is not visible 
5 
Non- 
vegetated 
Bare-soil 
(dry/wet) 
- 
• Red 
• Appears in black if soil is flooded 
6 
Shrimp farms/ 
Salt-beds 
• Rectangle sized small pond like 
structure, used for the production of 
shrimps or salt 
• Shrimp-farms usually have a 
shallow depth of water. Salt-bed 
may have water or may be in dry 
condition 
• Mixture of dark-red and light-red 
• Black rectangle shaped beds are 
often visible with red/bright ridges 
7 
Water 
- 
• Dark tone 
8 
Table 2. ALOS PALSAR interpretation keys for Southern Chittagong, Bangladesh (VV-> Red, VH-> Green and HV-> Blue) 
On PALSAR scene forest, plantation, forest mosaic, shrubs, 
agriculture/rural settlements with tree cover, bare-soil, shrimp- 
farms/salt-beds and water-body could be distinguished. Visually 
interpreted image was digitized on-screen to prepare forest 
(land) cover map. Several field-visits were done during the 
winter season of 2002-2003 and 2003-2004. 
3. RESULTS AND DISCUSSION 
Radar imagery is the result of radar signals, depends upon 
system parameters (wavelength, polarization and incident 
angle) and terrain parameters (complex dielectric constant, 
surface roughness, terrain geometry, and surface and volume 
scattering). Different elements of image interpretation (tone or 
colour, size, shape, texture, shadow, pattern, association etc.) 
assisted in radar image interpretation. In RGB (VV, VH and 
HV) visualization, forest appears in cyan, soil in red and water 
in black. Land-cover characteristics and interpretation remarks 
are listed in Table 2. The appearance of different land covers on 
the image is presented in Figure 3. 
Land cover map was prepared from Polarimetrie SAR data 
using visual interpretation technique and digitizing on-screen 
(Figure 4). Forests are usually concentrated in the hilly terrain. 
The locations of shrubs and degraded forests are close to the 
vicinity of settlements. Low-lying coastal zones dominated by 
shrimp-farms and salt-beds are distributed in the eastern and 
north-eastern part of the study area. Rural-settlements are 
located in the fringe of shrimp-farms and hills in the north, 
concentrated in central-east and sporadically distributed in the 
south-west. 
Four major land-covers are dominated in the study area: forest 
(5 955 ha), forest mosaic (5 678 ha), low-lying coastal zones 
(5 107 ha) and agriculture & bare-soil (10 561 ha). The class 
bare-soil may be contemporary and usually represents the 
cultivable agricultural lands on the plain-land. Bare soil on the 
hills could be the result of repeated disturbance on the forest. 
The details of land cover statistics are presented in Table 3.