The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Voi. XXXVII. Part B7. Beijing 2008 
(Ongi river interruption in south part: from imagery LANDSAT ETM+ 
data for 23 July, 1999 and 20 September, 2000) 
Figure 2. Location of the Ongi river 
2.3 Method 
Vegetation indices NVI and MSAVI 2 from the SPOT satellite 
for vegetation period from April to October 1998-2006 years 
used in the study area. Spectral bands Near Infrared 0.78-0.89 
pm, Short wave Infrared 1.58-1.75 p m were selected for the 
21-30 July, 1998 21-30 July, 1999 21-30 July, 2000 
21-30 July, 2004 21-30 July,2005 21-30 July, 2006 
0.022675 
0.099066 
0.175456 
0.251847 
0.328237 
0.404628 
0.481018 
0.557409 
0.633800 
Figure 3. Change of vegetation using MSAVI2 index between 
years 1998-2006 in the study area 
Figure 4. Change of vegetation using NDVI index between 
years 1998-2006 in the study area 
analysis. 
NDVI is normalizad ratio of the NIR and RED bands (1). 3 RESULTS AND DISCUSSION 
NDVI = 
NIR-RED 
NIR + RED 
(1) 
We made vegetation change analysis on for identifying of land 
degradation using remote sensing tools in Ongi river basin in 
Mongolia. 
Huete (1998) suggested a new vegetation index, which was 
designed to minimize the effect of the soil background, which 
he called the soil-adjusted vegetation index (SAVI) (2) 
developed of an iterated version of this vegetation, which is 
called MSAVI2 (3) 
SAVI = 
NIR - RED 
NIR + RED + L 
*(1 + L) 
(2) 
MSAVI 2 = 
2NIR +1 - ^{2NIR +1) 2 - S(NIR - RED) 
/2 
(3) 
As a results from the figure 5 and 6 of Onggi River basin’s 
vegetation loss has been increasingly 12000 square km. (since 
1998 year). Vegetation has a decreasing trend from both 
vegetation indexes MSAVI and NDVI (figure 5 and 6). This 
analyzes was compared with the results from the “NGO 
Ongiinhon” (www.onggiriver.com) research team which used 
ground truth data in recent years. 
Concluding that this number will be keeping to increase in the 
future. Future study should be focused not only on vegetation 
condition but should take analysis connected with socio 
economic data. 
MSAVI varies from 0.022675 to 0.633800 while NDVI values 
for vegetation is from 0.01 to 0.89. There is less greenness in 
south part area where is interruption river and mining activities 
(Figure 3 and 4).