Based on dimidiate pixel model and using Landsat TM/OLI remote sensing images of 4 periods in 25 years (1989—2014) and geological hazards investigation data, the authors analyzed the characteristics of vegetation spatial-temporal pattern in Yanchi County by GIS and discussed the relationship between vegetation coverage and geological hazards. The results showed that the vegetation coverage of study area took on the features of relatively high vegetation coverage in the east and relatively low vegetation coverage in the west. The average vegetation coverage was on the low side generally and presented the characteristics of increase-decrease-increase; correspondingly the vegetation appeared the repetitive process of restoration-degeneration-restoration but had a tendency of recovery as a whole, with restoration distributed in the southeast and northwest and degeneration in the mid-west. Geological hazards point density was high in the south and low in the north, which suggests that the hazards points were concentrated in the south and dispersed in the north. A negative correlation between vegetation coverage and density of geological hazards points was discovered, which suggests the regularity of density of geological hazards points descending with the increasing of vegetation coverage: the higher the vegetation, the lower the density of geological hazards points.
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