000			02608nam a22002417a 4500
003			ZW-GwMSU
005			20221129143053.0
008			221129b |||||||| |||| 00| 0 eng d
040			_aMSU _cMSU _erda
100			_aRulinda, Coco M _eauthor
245			_aVisualizing and quantifying the movement of vegetative drought using remote-sensing data and GIS _ccreated by Coco M. Rulinda ,Alfred Stein &Ulan D. Turdukulov
264			_aNetherlands: _bTaylor & Francis, _c2013.
336			_2rdacontent _atext _btxt
337			_2rdamedia _aunmediated _bn
338			_2rdacarrier _avolume _bnc
440			_vVolume , number ,
520			_aRemote-sensing-based drought monitoring methods provide fast and useful information for a sustainable management strategy of drought impact over a region. Common pixel-based monitoring methods are limited in the analysis of the dynamics of this impact at regional scale. For instance, these hardly allow us to quantify the movement of drought in space and time and to compare drought with rainfall deficits without losing the variability of these events within a region. This study proposed an object-based approach that allowed us to visualize and quantify the spatio-temporal movement of drought impact on vegetation, called vegetative drought, in a region. The GIS software Dynomap was used to extract and track objects. Measures of distance and angle were used for determining the speed and direction of vegetative drought and rainfall deficit objects, calculated from the National Oceanic and Atmospheric Administration's (NOAA's) normalized difference vegetation index and rainfall estimates data. The methods were applied to the two rainy seasons during the drought year 1999 in East Africa. Results showed that vegetative drought objects moved into the southwestern direction at an average angle of −138.5° during the first season and −144.5° during the second season. The speed of objects varied between 38 km dekad−1 and 185 km dekad−1 during the first season and between 33 km dekad−1 and 144 km dekad−1 during the second season, reflecting the rate of spread between dekads. Vegetative drought objects close to rainfall deficit objects showed similar trajectories and sometimes regions overlapped. This indicated that the two events are related. We conclude that a spatiotemporal relationship existed between the two types of events and that this could be quantified.
650			_adrought
650			_atrajectories
650			_aspatio-temporal objects
856			_uhttps://doi.org/10.1080/13658816.2012.723712
942			_2lcc _cJA
999			_c160667 _d160667