Spatio-Temporal Analysis for Monitoring Urban Growth Using Geospatial Tools: a Case Study of Adama City, Ethiopia
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Date
2018-05-05
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Addis Ababa University
Abstract
Rapid and unprecedented urban growth is becoming the characteristics of cities in developing
countries. Hence, it is normal to assess and monitor urban growth changes using necessary to
quantify urban sprawl that provide paramount information for, policy makers, resource managers and
urban planners. This study was conducted in Adama city to examine and quantify spatio-temporal
trends and patterns of urban growth during 1994–2017. Landsat5 TM image for 1994 and aerial
photos of 2004 and 2017 were used for this study. Three different land-cover maps produced at
different intervals between 1994 and 2017 were used to evaluate and analyze urban growth visually
and quantitatively. The satellite images were classified and land-use/land-cover maps were produced
using maximum likelihood supervised classification method. The classification process was checked
by producer’s, user’s, overall accuracy and Kappa statistic accuracy assessments from confusion
metrics. Results show acceptable agreement between the classified maps and reference data with a
producer’s accuracy value >70.6%, and user’s accuracy >80%. Post classification change detection
analysis and selected spatial metric indices calculation were made to detect, assess and monitor
urban growth and the quantify LU/LC changes in the study area. Change detection analysis indicated
that Adama is growing rapidly with an average growth rate of 7.3% per year during1944–2017. The
built-up area was 45.26 km2, 74.4 km2and 153.67km2, respectively in 1994, 2004 and 2017, with
annual growth rates of 6.4% and 8.1% in the two study phases. The areas had annual spatial
expansion indices of 6.4% and 8.19%, respectively during the periods 1994−2004 and
2004−2017.From spatial metrics analysis, combined number of built-up area patches was 345,
473and 717 for the years 1994, 2004 and 2017. The increase in the number of patches all through the
study periods shows the rapid urban growth process in the study area. Therefore, it is time for policy
makers, city managers and urban planners to plan and cope up with the pace of Adama urban growth
depending on with proper implementation.
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Keywords
Change Detection, Spatial Metrics, Urban Growth, Land-Use/Land-Cover Change