UCLA
Remote Sensing
Vegetation Change
Vegetation Change
Vegetation Change
Methods
We will be conducting a study of Yemen’s agricultural productivity over the period 2015-present, roughly the length of the Saudi led bombing campaign in the country, through comparisons of agriculture extent through NDVI classifications of Landsat 8 imagery at multiple timescales. We have collected imagery for a subset of the western portion of the country that is heavy in agriculture and has been extensively bombed by the Saudi Coalition. abandonment, and direct bombing of agricultural lands and infrastructure are direct results of conflict in the region with implications for agricultural productivity (the largest industry in Yemen) and food production. We intend to calculate the extent of agriculture in the region before the war as compared to current and measure the percent change in cultivation.
Data Collection
LANDSAT 8 images of the study region were taken on April 29, 2015 and March 07, 2018. All dataset has been downloaded from the United States Geological Survey Glovis platform.
Both images has been selected for the same season and less influence by clouds.
NDVI
The normalized difference vegetation index (NDVI) is a simple graphical indicator that can be used to analyze remote sensing measurements. The range of NDVI index is -1 to 1
The selected region has been the NDVI image by ENVI software. The whole image present as black and white. The white region belongs to the positive value of NDVI index which has vegetation covered.
Classifying the Data
In order to show the vegetation change clearly, this image has been classified the region of vegetation covered based on the ROIs from Ban Thresholds. The range has been selected for vegetation is 0.13 to 1.
ndvi difference map
This image was created by Band Math to overlap the NDVI image from 2015 and 2018. In this selected region, only vegetation covered area has been calculated. Other regions were masked. The blue color present vegetation increasing, and red color show vegetation decreasing.