M. Gebreslasie - Academia.edu (original) (raw)
Papers by M. Gebreslasie
Forest structural assessment using remote sensing technologies:
Remote Sensing for Agriculture, Ecosystems, and Hydrology IX, 2007
The main goal of this research was to investigate the structural-spectral interactions that exist... more The main goal of this research was to investigate the structural-spectral interactions that exist in managed, homogeneous, even-aged Eucalyptus plantations through plot-level volume and basal area modelling in Kwazulu-Natal, South Africa. Eucalyptus plantations used in this study range between four and ten years old. Small-footprint light detection and ranging (lidar; ALTM 3033 two-return laser system; 0.2 mrad footprint, 33 kHz
International Journal of Applied Earth Observation and Geoinformation, 2010
Southern Forests: a Journal of Forest Science, 2009
... Atmospheric correction of spectral imagery: evaluation of the ... An investigation into using... more ... Atmospheric correction of spectral imagery: evaluation of the ... An investigation into using textural analysis and change detection techniques on medium and high spatial resolution imagery for monitoring plantation forestry operation, PhD thesis, University of KwaZulu ...
Southern Hemisphere Forestry Journal, 2007
The Forestry and Forest Products Research Centre (CSIR), University of KwaZulu-Natal and MONDI Bu... more The Forestry and Forest Products Research Centre (CSIR), University of KwaZulu-Natal and MONDI Business Paper have recently embarked on a remote sensing cooperative. The primary focus of this cooperative is to explore the potential benefits associated with using remote sensing for forestry-related activities. A subproject within the cooperative is exploring the utility of various remote sensing technologies for forest structural assessment. This paper reports on the primary findings of a state-of-the-art review conducted by members of the cooperative and seeks to inform and contribute to the development of focused research projects. Both active and passive sensors are reviewed at varying spatial scales focusing primarily on accuracies attained. Medium-resolution studies focus on contextual forest attributes while high-resolution studies focused on location-based forest variables. Results from research consulted indicate that while remote sensing has a strong theoretical background, there are several limiting factors that need to be explored within a South African context. These include the saturation of satellite signals in mature forests, underestimation of tree heights using LiDAR data and the cost of LiDAR surveys. The review ends with recommendations for future research activities.
International Journal of Remote Sensing, 2011
... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. For... more ... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. Forest structural assessment using remote sensing technologies: an overview of the current state of the art. Southern Hemisphere Forestry Journal , 69: 183203. View all references). ...
International Journal of Remote Sensing, 2011
The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimat... more The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimation of forest structural attributes-for example, stems per hectare (SPHA), diameter at breast height (DBH), mean tree height (MTH), basal area (BA) and volume in plantation forest environments-was assessed in this study. The relationships of these forest structural attributes to statistical image texture from IKONOS imagery were analysed. The coefficients of determination (R 2) of multilinear regression models developed for the estimation of SPHA, DBH, MTH, BA and volume using statistical texture features from multispectral data were 0.63, 0.68, 0.81, 0.86 and 0.86, respectively. When the statistical texture features from panchromatic data were applied, the R 2 for the respective forest structural attributes increased by 25%, 31%, 6%, 0.2% and 0.2%, respectively. Artificial neural network (ANN) models produced strong and significant relationships between estimated and actual measures of SPHA, DBH, MTH, BA and volume with an R 2 of 0.83, 0.83, 0.90, 0.90 and 0.92, respectively, based on multispectral IKONOS data. Based on panchromatic IKONOS imagery, the R 2 for the respective forest structural attributes increased by 18%, 12%, 5%, 3% and 6%, respectively. Results such as these bode well for the application of high spatial resolution imagery to forest structural assessment.
International Journal of Remote Sensing, 2011
The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimat... more The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimation of forest structural attributes-for example, stems per hectare (SPHA), diameter at breast height (DBH), mean tree height (MTH), basal area (BA) and volume in plantation forest environments-was assessed in this study. The relationships of these forest structural attributes to statistical image texture from IKONOS imagery were analysed. The coefficients of determination (R 2) of multilinear regression models developed for the estimation of SPHA, DBH, MTH, BA and volume using statistical texture features from multispectral data were 0.63, 0.68, 0.81, 0.86 and 0.86, respectively. When the statistical texture features from panchromatic data were applied, the R 2 for the respective forest structural attributes increased by 25%, 31%, 6%, 0.2% and 0.2%, respectively. Artificial neural network (ANN) models produced strong and significant relationships between estimated and actual measures of SPHA, DBH, MTH, BA and volume with an R 2 of 0.83, 0.83, 0.90, 0.90 and 0.92, respectively, based on multispectral IKONOS data. Based on panchromatic IKONOS imagery, the R 2 for the respective forest structural attributes increased by 18%, 12%, 5%, 3% and 6%, respectively. Results such as these bode well for the application of high spatial resolution imagery to forest structural assessment.
... attributes : graphical modelling. Journal Title: CSIR Science Scope; Volume: Volume 2; Issue:... more ... attributes : graphical modelling. Journal Title: CSIR Science Scope; Volume: Volume 2; Issue: Issue 4; Publication Date: 2008; Pages: 5 - 6; Authors: Wesley Roberts; MichaelGebreslasie; Solomon Tesfamichael; Thamsanqa Mzinyane; ...
Journal of Mathematics and Statistics, 2012
Predicting the trend of precipitation is a difficult task in meteorology and environmental scienc... more Predicting the trend of precipitation is a difficult task in meteorology and environmental sciences. Statistical approaches from time series analysis provide an alternative way for precipitation prediction. The ARIMA model incorporating seasonal characteristics, which is referred to as seasonal ARIMA model was presented. The time series data is the monthly precipitation data in Yantai, China and the period is from 1961 to 2011. The model was denoted as SARIMA (1, 0, 1) (0, 1, 1) 12 in this study. We first analyzed the stability and correlation of the time series. Then we predicted the monthly precipitation for the coming three yesrs. The results showed that the model fitted the data well and the stochastic seasonal fluctuation was sucessfuly modeled. Seasonal ARIMA model was a proper method for modeling and predicting the time series of monthly percipitation.
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
South African Journal of Geomatics, 2014
Understanding urban spatial growth is critical for sustainable urban infrastructure and service p... more Understanding urban spatial growth is critical for sustainable urban infrastructure and service planning. Urban growth information is an important input into predicting future land cover and land use change and sustainable growth management. Rapid urbanization has resulted in expanded urban land use and has led to population explosions in urban areas and undesirable environmental impacts in South Africa. This research is aimed at studying urban spatial growth of Rustenburg city in South Africa from 2007 to 2012 using temporal imagery acquired by Satellite Pour l'Observation de la Terra (SPOT) 5 satellite. Multi-temporal images acquired in 2007, 2009 and 2012 were used to assess urban spatial growth of Rustenburg. Post-classification change detection method was used to quantify urban growth. For the purpose of this study, only two classes, urban and non-urban land use classes, were mapped and assessed. The urban spatial growth between 2007 and 2009 was 16.8% while 8.7% urban growth was observed between 2009 and 2012. The total spatial urban growth between 2007 and 2012 was 25.5%. This information can be used by the municipal authorities and decision makers as input during urban and environmental planning.
International Journal of Remote Sensing, 2011
... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. For... more ... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. Forest structural assessment using remote sensing technologies: an overview of the current state of the art. Southern Hemisphere Forestry Journal , 69: 183203. View all references). ...
Forest structural assessment using remote sensing technologies:
Remote Sensing for Agriculture, Ecosystems, and Hydrology IX, 2007
The main goal of this research was to investigate the structural-spectral interactions that exist... more The main goal of this research was to investigate the structural-spectral interactions that exist in managed, homogeneous, even-aged Eucalyptus plantations through plot-level volume and basal area modelling in Kwazulu-Natal, South Africa. Eucalyptus plantations used in this study range between four and ten years old. Small-footprint light detection and ranging (lidar; ALTM 3033 two-return laser system; 0.2 mrad footprint, 33 kHz
International Journal of Applied Earth Observation and Geoinformation, 2010
Southern Forests: a Journal of Forest Science, 2009
... Atmospheric correction of spectral imagery: evaluation of the ... An investigation into using... more ... Atmospheric correction of spectral imagery: evaluation of the ... An investigation into using textural analysis and change detection techniques on medium and high spatial resolution imagery for monitoring plantation forestry operation, PhD thesis, University of KwaZulu ...
Southern Hemisphere Forestry Journal, 2007
The Forestry and Forest Products Research Centre (CSIR), University of KwaZulu-Natal and MONDI Bu... more The Forestry and Forest Products Research Centre (CSIR), University of KwaZulu-Natal and MONDI Business Paper have recently embarked on a remote sensing cooperative. The primary focus of this cooperative is to explore the potential benefits associated with using remote sensing for forestry-related activities. A subproject within the cooperative is exploring the utility of various remote sensing technologies for forest structural assessment. This paper reports on the primary findings of a state-of-the-art review conducted by members of the cooperative and seeks to inform and contribute to the development of focused research projects. Both active and passive sensors are reviewed at varying spatial scales focusing primarily on accuracies attained. Medium-resolution studies focus on contextual forest attributes while high-resolution studies focused on location-based forest variables. Results from research consulted indicate that while remote sensing has a strong theoretical background, there are several limiting factors that need to be explored within a South African context. These include the saturation of satellite signals in mature forests, underestimation of tree heights using LiDAR data and the cost of LiDAR surveys. The review ends with recommendations for future research activities.
International Journal of Remote Sensing, 2011
... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. For... more ... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. Forest structural assessment using remote sensing technologies: an overview of the current state of the art. Southern Hemisphere Forestry Journal , 69: 183203. View all references). ...
International Journal of Remote Sensing, 2011
The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimat... more The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimation of forest structural attributes-for example, stems per hectare (SPHA), diameter at breast height (DBH), mean tree height (MTH), basal area (BA) and volume in plantation forest environments-was assessed in this study. The relationships of these forest structural attributes to statistical image texture from IKONOS imagery were analysed. The coefficients of determination (R 2) of multilinear regression models developed for the estimation of SPHA, DBH, MTH, BA and volume using statistical texture features from multispectral data were 0.63, 0.68, 0.81, 0.86 and 0.86, respectively. When the statistical texture features from panchromatic data were applied, the R 2 for the respective forest structural attributes increased by 25%, 31%, 6%, 0.2% and 0.2%, respectively. Artificial neural network (ANN) models produced strong and significant relationships between estimated and actual measures of SPHA, DBH, MTH, BA and volume with an R 2 of 0.83, 0.83, 0.90, 0.90 and 0.92, respectively, based on multispectral IKONOS data. Based on panchromatic IKONOS imagery, the R 2 for the respective forest structural attributes increased by 18%, 12%, 5%, 3% and 6%, respectively. Results such as these bode well for the application of high spatial resolution imagery to forest structural assessment.
International Journal of Remote Sensing, 2011
The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimat... more The suitability of optical IKONOS satellite data (multispectral and panchromatic) for the estimation of forest structural attributes-for example, stems per hectare (SPHA), diameter at breast height (DBH), mean tree height (MTH), basal area (BA) and volume in plantation forest environments-was assessed in this study. The relationships of these forest structural attributes to statistical image texture from IKONOS imagery were analysed. The coefficients of determination (R 2) of multilinear regression models developed for the estimation of SPHA, DBH, MTH, BA and volume using statistical texture features from multispectral data were 0.63, 0.68, 0.81, 0.86 and 0.86, respectively. When the statistical texture features from panchromatic data were applied, the R 2 for the respective forest structural attributes increased by 25%, 31%, 6%, 0.2% and 0.2%, respectively. Artificial neural network (ANN) models produced strong and significant relationships between estimated and actual measures of SPHA, DBH, MTH, BA and volume with an R 2 of 0.83, 0.83, 0.90, 0.90 and 0.92, respectively, based on multispectral IKONOS data. Based on panchromatic IKONOS imagery, the R 2 for the respective forest structural attributes increased by 18%, 12%, 5%, 3% and 6%, respectively. Results such as these bode well for the application of high spatial resolution imagery to forest structural assessment.
... attributes : graphical modelling. Journal Title: CSIR Science Scope; Volume: Volume 2; Issue:... more ... attributes : graphical modelling. Journal Title: CSIR Science Scope; Volume: Volume 2; Issue: Issue 4; Publication Date: 2008; Pages: 5 - 6; Authors: Wesley Roberts; MichaelGebreslasie; Solomon Tesfamichael; Thamsanqa Mzinyane; ...
Journal of Mathematics and Statistics, 2012
Predicting the trend of precipitation is a difficult task in meteorology and environmental scienc... more Predicting the trend of precipitation is a difficult task in meteorology and environmental sciences. Statistical approaches from time series analysis provide an alternative way for precipitation prediction. The ARIMA model incorporating seasonal characteristics, which is referred to as seasonal ARIMA model was presented. The time series data is the monthly precipitation data in Yantai, China and the period is from 1961 to 2011. The model was denoted as SARIMA (1, 0, 1) (0, 1, 1) 12 in this study. We first analyzed the stability and correlation of the time series. Then we predicted the monthly precipitation for the coming three yesrs. The results showed that the model fitted the data well and the stochastic seasonal fluctuation was sucessfuly modeled. Seasonal ARIMA model was a proper method for modeling and predicting the time series of monthly percipitation.
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
South African Journal of Geomatics, 2014
Understanding urban spatial growth is critical for sustainable urban infrastructure and service p... more Understanding urban spatial growth is critical for sustainable urban infrastructure and service planning. Urban growth information is an important input into predicting future land cover and land use change and sustainable growth management. Rapid urbanization has resulted in expanded urban land use and has led to population explosions in urban areas and undesirable environmental impacts in South Africa. This research is aimed at studying urban spatial growth of Rustenburg city in South Africa from 2007 to 2012 using temporal imagery acquired by Satellite Pour l'Observation de la Terra (SPOT) 5 satellite. Multi-temporal images acquired in 2007, 2009 and 2012 were used to assess urban spatial growth of Rustenburg. Post-classification change detection method was used to quantify urban growth. For the purpose of this study, only two classes, urban and non-urban land use classes, were mapped and assessed. The urban spatial growth between 2007 and 2009 was 16.8% while 8.7% urban growth was observed between 2009 and 2012. The total spatial urban growth between 2007 and 2012 was 25.5%. This information can be used by the municipal authorities and decision makers as input during urban and environmental planning.
International Journal of Remote Sensing, 2011
... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. For... more ... 200728. Roberts, JW, Gebreslasie, MT, Tesfamichael, S., Van Aardt, JN and Ahmed, FB 2007. Forest structural assessment using remote sensing technologies: an overview of the current state of the art. Southern Hemisphere Forestry Journal , 69: 183203. View all references). ...