Spatiotemporal Modeling of Urban Expansion: In a case of Robe Towen Using Remote sensing and GIS Techniques
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Date
2023-07
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Addis Ababa University
Abstract
Urbanization is the most powerful and visible force that has fundamental changes Land Use
Land Cover around globe. This study was conducted in Robe town to model spatio-temporal of
expansion during 2006–2021. SPOT image for 2006 and 2016 as well as Sentinel 2A for image
were used for this study. Three different land-cover maps produced at different intervals between
2006 and 2021 were used to evaluate and analyze urban expansion visually and quantitatively.
The satellite images were classified and land-use/land-cover maps were produced using Object
Based Image Classification using KNN classification method using Envi 5.3 and predict
Expansion of Robe Town using CA-Markov model. The classification process was checked by
overall accuracy and Kappa statistic accuracy assessments from confusion metrics. Results show
acceptable agreement between the classified maps and reference data with overall accuracy
value 91% for 2006, 88% for2016 and 93% for 2021. Kappa accuracy value 0.89, 0.85 and 0.91
for classified satellite image of 2006, 2016 and 2021 respectively. Post classification change
detection analysis and selected spatial metric indices calculation were made to detect, assess
pattern of urban expansion in the study area. Change detection analysis indicated that Robe
town is growing rapidly with an average growth rate of 7.8% year during2006–2021. The builtup
area was 854 hectare, 1067hectare and 1740 hectare, respectively in 2006, 2016 and 2021,
with annual growth rates of 2% and 7.8% in the two study phases respectively during the periods
2006-2016 and 2016-2021. From spatial metrics analysis, largest patch index of built-up area
was 7%, 10% and 15% for the years 2006, 2016 and 2021. The increase in the number of largest
patch index all through the study periods shows the rapid urban growth process in the study
area.CA-Markov model used for modeling and validating kappa statistic is moderate and
acceptable to predict for future (2050).Therefore, it is time for policy makers, city managers and
urban planners to plan and cope up with the pace of Robe town urban expansion depending on
with proper implementation.