The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency fo... more The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency for surveyors to depend on local vertical datum for height determination. This is due to the fact that, currently it is possible to determine heights referred to the geoid using GPS and then transform these heights so that they refer to the local vertical datum and vice versa. This book focuses on determination of transformation parameters between The Tanzania National Levelling Datum (TNLD) and the geoid, and computation of Digital Finite Element Height Reference Surface (DFHRS) for GPS heighting.
The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency fo... more The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency for surveyors to depend on local vertical datum for height determination. This is due to the fact that, currently it is possible to determine heights referred to the geoid using GPS and then transform these heights so that they refer to the local vertical datum and vice versa. This book focuses on determination of transformation parameters between The Tanzania National Levelling Datum (TNLD) and the geoid, and computation of Digital Finite Element Height Reference Surface (DFHRS) for GPS heighting.
Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. Th... more Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. This modernization program is such that in future it will not be necessary for the Surveys and Mapping Division (DSM) to create and maintain the old spirit leveled orthometric height benchmarks. The DSM shall only be required to measure and publish ellipsoidal heights and GPS derived orthometric heights for various survey markers. This paper focuses on the determination of the transformation parameters between the Tanzania National Levelling Datum (TNLD) and the geoid for facilitating GPS heighting in Tanzania. Least squares estimates of the transformation parameters have been determined from orthometric heights in the Tanzania Primary Levelling Network (TPLN) and GPS derived orthometric heights referred to a preliminary model of the African geoid called AGP2003 and a geoid implied by the EGM96 geopotential coefficients. Two transformation models were considered: The Molodensky's tran...
Abstract: The purpose of this paper is to estimate the water balance in a semi-arid environment w... more Abstract: The purpose of this paper is to estimate the water balance in a semi-arid environment with limited in situ data using a remote sensing approach. We focus on the Lake Manyara catchment, located within the East African Rift of northern Tanzania. We use a distributed conceptual hydrological model driven by remote sensing data to study the spatial and temporal variability of water balance parameters within the catchment. Satellite gravimetry GRACE data is used to verify the trends of the inferred lake level changes. The results show that the lake undergoes high spatial and temporal variations, characteristic of a semi-arid climate with high evaporation and low rainfall. We observe that the Lake Manyara water balance and GRACE equivalent water depth show comparable trends; a decrease after 2002 followed by a sharp increase in 2006–2007. Our modeling confirms the importance of the 2006–2007 Indian Ocean Dipole fluctuation in replenishing the groundwater reservoirs of East Africa...
Many supervised classification algorithms have been proposed, however, they are rarely evaluated ... more Many supervised classification algorithms have been proposed, however, they are rarely evaluated for specific application. This research examines the performance of machine learning classifiers support vector machine (SVM), neural network (NN), Random Forest (RF) against maximum classifier (MLC) (traditional supervised classifier) in forest resources and land cover categorization, based on combination of Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) and Landsat Thematic Mapper (TM) data, in Northern Tanzania. Various data categories based on Landsat TM surface reflectance, ALOS PALSAR backscattering and their derivatives were generated for various classification scenarios. Then a separate and joint processing of Landsat and ALOS PALSAR data were executed using SVM, NN, RF and ML classifiers. The overall classification accuracy (OA), kappa coefficient (KC) and F1 score index values were computed. The result proves the robustness o...
Groundwater is a precious resource that covers wide geographical extent. Proper evaluation is req... more Groundwater is a precious resource that covers wide geographical extent. Proper evaluation is required in order to ensure prudent use of groundwater resources. Lack of proper knowledge accounting distribution of groundwater potential zones (GWPZS) has a negative implication on groundwater exploitation and management as the area will be explored with higher uncertainties. The objective of this study is to delineate the GWPZS in Dodoma City, Tanzania, using a Geographic Information System (GIS) based multi-criteria decision analysis (MCDA) technique. Various thematic layers which influence groundwater occurrence such as lithology, lineament density, drainage density, slope and land use/cover maps were used. The final groundwater potential map was prepared by assigning appropriate weightage and theme classes’ ranks to different thematic layers using Saaty’s analytic hierarchy approach. Following weightage and ranking, the rasterized and reclassified thematic layers were integrated usin...
Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. Th... more Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. This modernization program is such that in future it will not be necessary for the Surveys and Mapping Division (DSM) to create and maintain the old spirit leveled orthometric height benchmarks. The DSM shall only be required to measure and publish ellipsoidal heights and GPS derived orthometric heights for various survey markers. This paper focuses on the determination of the transformation parameters between the Tanzania National Levelling Datum (TNLD) and the geoid for facilitating GPS heighting in Tanzania. Least squares estimates of the transformation parameters have been determined from orthometric heights in the Tanzania Primary Levelling Network (TPLN) and GPS derived orthometric heights referred to a preliminary model of the African geoid called AGP2003 and a geoid implied by the EGM96 geopotential coefficients. Two transformation models were considered: The Molodensky's tran...
The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency fo... more The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency for surveyors to depend on local vertical datum for height determination. This is due to the fact that, currently it is possible to determine heights referred to the geoid using GPS and then transform these heights so that they refer to the local vertical datum and vice versa. This book focuses on determination of transformation parameters between The Tanzania National Levelling Datum (TNLD) and the geoid, and computation of Digital Finite Element Height Reference Surface (DFHRS) for GPS heighting.
The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency fo... more The advent of the Global Positioning System (GPS) as a surveying tool has changed the tendency for surveyors to depend on local vertical datum for height determination. This is due to the fact that, currently it is possible to determine heights referred to the geoid using GPS and then transform these heights so that they refer to the local vertical datum and vice versa. This book focuses on determination of transformation parameters between The Tanzania National Levelling Datum (TNLD) and the geoid, and computation of Digital Finite Element Height Reference Surface (DFHRS) for GPS heighting.
Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. Th... more Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. This modernization program is such that in future it will not be necessary for the Surveys and Mapping Division (DSM) to create and maintain the old spirit leveled orthometric height benchmarks. The DSM shall only be required to measure and publish ellipsoidal heights and GPS derived orthometric heights for various survey markers. This paper focuses on the determination of the transformation parameters between the Tanzania National Levelling Datum (TNLD) and the geoid for facilitating GPS heighting in Tanzania. Least squares estimates of the transformation parameters have been determined from orthometric heights in the Tanzania Primary Levelling Network (TPLN) and GPS derived orthometric heights referred to a preliminary model of the African geoid called AGP2003 and a geoid implied by the EGM96 geopotential coefficients. Two transformation models were considered: The Molodensky's tran...
Abstract: The purpose of this paper is to estimate the water balance in a semi-arid environment w... more Abstract: The purpose of this paper is to estimate the water balance in a semi-arid environment with limited in situ data using a remote sensing approach. We focus on the Lake Manyara catchment, located within the East African Rift of northern Tanzania. We use a distributed conceptual hydrological model driven by remote sensing data to study the spatial and temporal variability of water balance parameters within the catchment. Satellite gravimetry GRACE data is used to verify the trends of the inferred lake level changes. The results show that the lake undergoes high spatial and temporal variations, characteristic of a semi-arid climate with high evaporation and low rainfall. We observe that the Lake Manyara water balance and GRACE equivalent water depth show comparable trends; a decrease after 2002 followed by a sharp increase in 2006–2007. Our modeling confirms the importance of the 2006–2007 Indian Ocean Dipole fluctuation in replenishing the groundwater reservoirs of East Africa...
Many supervised classification algorithms have been proposed, however, they are rarely evaluated ... more Many supervised classification algorithms have been proposed, however, they are rarely evaluated for specific application. This research examines the performance of machine learning classifiers support vector machine (SVM), neural network (NN), Random Forest (RF) against maximum classifier (MLC) (traditional supervised classifier) in forest resources and land cover categorization, based on combination of Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) and Landsat Thematic Mapper (TM) data, in Northern Tanzania. Various data categories based on Landsat TM surface reflectance, ALOS PALSAR backscattering and their derivatives were generated for various classification scenarios. Then a separate and joint processing of Landsat and ALOS PALSAR data were executed using SVM, NN, RF and ML classifiers. The overall classification accuracy (OA), kappa coefficient (KC) and F1 score index values were computed. The result proves the robustness o...
Groundwater is a precious resource that covers wide geographical extent. Proper evaluation is req... more Groundwater is a precious resource that covers wide geographical extent. Proper evaluation is required in order to ensure prudent use of groundwater resources. Lack of proper knowledge accounting distribution of groundwater potential zones (GWPZS) has a negative implication on groundwater exploitation and management as the area will be explored with higher uncertainties. The objective of this study is to delineate the GWPZS in Dodoma City, Tanzania, using a Geographic Information System (GIS) based multi-criteria decision analysis (MCDA) technique. Various thematic layers which influence groundwater occurrence such as lithology, lineament density, drainage density, slope and land use/cover maps were used. The final groundwater potential map was prepared by assigning appropriate weightage and theme classes’ ranks to different thematic layers using Saaty’s analytic hierarchy approach. Following weightage and ranking, the rasterized and reclassified thematic layers were integrated usin...
Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. Th... more Tanzania is embarking on a height modernization programme in support of the AFREF initiatives. This modernization program is such that in future it will not be necessary for the Surveys and Mapping Division (DSM) to create and maintain the old spirit leveled orthometric height benchmarks. The DSM shall only be required to measure and publish ellipsoidal heights and GPS derived orthometric heights for various survey markers. This paper focuses on the determination of the transformation parameters between the Tanzania National Levelling Datum (TNLD) and the geoid for facilitating GPS heighting in Tanzania. Least squares estimates of the transformation parameters have been determined from orthometric heights in the Tanzania Primary Levelling Network (TPLN) and GPS derived orthometric heights referred to a preliminary model of the African geoid called AGP2003 and a geoid implied by the EGM96 geopotential coefficients. Two transformation models were considered: The Molodensky's tran...
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