D. Lo Seen

D. Lo Seen
Cirad - La recherche agronomique pour le développement | CIRAD · Unité Mixte de Recherche Territoire Environnement Télédétection et Information Spatiale (TETIS)

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105
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4,044
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Citations since 2016
26 Research Items
1821 Citations
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300

Publications

Publications (105)
Article
Full-text available
The availability of crop type reference datasets for satellite image classification is very limited for complex agricultural systems as observed in developing and emerging countries. Indeed, agricultural land use is very dynamic, agricultural censuses are often poorly georeferenced and crop types are difficult to interpret directly from satellite i...
Preprint
Full-text available
The availability of crop type reference datasets for satellite image classification is very limited for complex agricultural systems as observed in developing and emerging countries. Indeed, agricultural land use is very dynamic, agricultural census are often poorly georeferenced, and crop types are difficult to photo-interpret directly from satell...
Article
Full-text available
The ALBOMAURICE software runs a mosquito population dynamics model to predict the temporal and spatial abundance of Aedes albopictus, the dengue disease vector in Mauritius. For each vector surveillance zone, it solves a system of ordinary differential equations describing different stages of the mosquito life cycle. ALBOMAURICE uses daily rainfall...
Article
Full-text available
Smallholder agriculture provides 90 % of primary food production in developing countries. Its mapping is thus a key element for national food security. Remote sensing is widely used for crop mapping, but it is underperforming for smallholder agriculture due to several constraints like small field size, fragmented landscape, highly variable cropping...
Article
Nowadays, modern Earth Observation systems continuously generate huge amounts of data. A notable example is the Sentinel-2 Earth Observation mission, developed by the European Space Agency as part of the Copernicus Programme, which supplies images from the whole planet at high spatial resolution (up to 10 m) with unprecedented revisit time (every 5...
Article
Remote sensing data, crop modelling, and statistical methods are combined in an original method to overcome current limitations of crop yield estimation. It is then tested for timely estimation of maize grain yields and their year-on-year variability in Burkina Faso. Outputs from the SARRA-O crop model were used as a proxy for observed data for cal...
Article
In the Sahel, crop growth and yield are strongly linked to climate fluctuations. The low and erratic rainfall the Sahel region has experienced for several years led to poor harvests, associated with dramatic food crises and famines. Consequently, numerous studies were conducted to develop innovative techniques to estimate crop yield based on satell...
Article
In a context of strong climatic and economic uncertainty in West Africa, agricultural statistics reveal interannual variations in the proportions of crops. The underlying causes of these variations remain, however, poorly documented although their understanding is essential for crop production monitoring and agricultural policyrelated decision-supp...
Article
In a context of fast land changes due to human activity, the old “Malthus vs. Boserup” debate about human pressure on natural resources is more than ever a prevalent subject. We illustrate this debate with an example based on the Tuy Province in West Burkina Faso, which has known an important development these last fifteen years, as mainly observab...
Article
Full-text available
In response to the need for generic remote sensing tools to support large-scale agricultural monitoring, we present a new approach for regional-scale mapping of agricultural land-use systems (ALUS) based on object-based Normalized Difference Vegetation Index (NDVI) time series analysis. The approach consists of two main steps. First, to obtain rela...
Article
Models are increasingly being used to investigate agro-ecosystems dynamics, although processes interacting at different scales remain difficult to consider. When upscaled or downscaled based on aggregation or disaggregation methods, information is generally distorted. This study explores agro-ecosystem modelling using an interaction graph-based mod...
Presentation
Since the Sahelian population livelihood relies mainly on agropastoral activities, accurate information on biomass productivity dynamics and the underlying drivers are needed to manage a wide range of issues such as food security. This study aims to contribute to a better understanding of these drivers in rangeland and cropland, both at the Sahel a...
Article
A wide range of environmental and societal issues such as food security policy implementation requires accurate information on biomass productivity and its underlying drivers at both regional and local scales. While many studies in West Africa are conducted with coarse resolution earth observation data, few have tried to relate vegetation trends to...
Article
Abstract This paper reflects on collaborative landscape research conducted in Reunion Island, an outermost region of the European Union. On this 2,500 km2 tropical island also considered a major international biodiversity hotspot, land-use planners must address important challenges, especially growing population densities and urban sprawl that caus...
Chapter
Full-text available
The territory, defined as a geographical space as appropriated and perceived by individual or collective actors, evolves in space and time under the effects of natural and anthropogenic factors in an institutional, political and social context. It is therefore inherently dynamic. Planning and decision-making for territories consequently require a d...
Article
Full-text available
China has been through a period of remarkable urban sprawl since the reform and opening-up policy in 1978, with the highest urbanization occurring in the coastal zones. Sustainable urban development requires a better understanding of the spatiotemporal characteristics of urbanization. This study systematically explored urban sprawl in Chinese coast...
Article
A collaborative framework using a spatially explicit modeling platform, Ocelet, has been designed as a territorial planning support tool in Reunion Island, where urban sprawl is a major issue. Urban development scenarios and models were constructed collectively by a group of specialists from some twenty institutions. The first group of workshops fo...
Poster
Full-text available
Rural areas of West Burkina Faso have seen notable transformations these last two decades due to high population growth and farming systems evolution. Satellite images acquired frequently and covering large areas are essential for detecting such landscape changes and long term trends. However, these images generally have coarse spatial resolutions...
Article
This paper introduces Ocelet, a domain specific language and simulation tool for modelling changes in geographical landscapes. It is characterised by the use of interaction graphs (graphs with interaction functions on their edges) to represent the system as composed of processes, each involving several entities distributed in space that are in inte...
Article
Full-text available
We present a new landscape-modelling framework based on a domain-specific language called Ocelet that is used to question our understanding of how mangrove forests cope with fast-changing muddy seashores. For the demonstration, we selected the coast of French Guiana where mangrove physiognomy and extent continuously vary due to successive and recur...
Technical Report
Full-text available
Ce rapport a pour objectif de faire un état des lieux des usages des technologies satellitaires dans le développement et l’analyse des agricultures africaines, afin de mieux cerner les difficultés actuelles, identifier les contraintes sur lesquelles la recherche et le partenariat peuvent avoir un effet, et imaginer les actions nécessaires pour leve...
Article
For the semiarid Sahelian region, climate variability is one of the most important risks of food insecurity. Field experimentations as well as crop modeling are helpful tools for the monitoring and the understanding of yields at local scale. However, extrapolation of these methods at a regional scale remains a demanding task. Remote sensing observa...
Article
Un dispositif partenarial mobilisant un outil de simulation paysagère, Ocelet, a été conçu comme support d’un exercice de prospective territoriale sur une intercommunalité de l’île de La Réunion où le mitage agricole représente un enjeu important. La démarche consiste à coconstruire, au sein d’une arène d’une vingtaine d’institutions, des scénarios...
Conference Paper
Full-text available
In West Africa, the spatiotemporal variability of rainfall is often considered as one of the most important causes of food insecurity. Satellite Rainfall Estimates products provide synoptic, objective and timely information on the rainfall distribution and thus are particularly relevant tools for crop monitoring over large areas. This study assesse...
Conference Paper
Urbanization is nowadays a global issue, and the encroachment of urban on non-urban land, especially arable land, has become a common phenomenon in most developing countries. For instance, Chinese coastal zone has witnessed incredibly rapid urban and industrial development since 1978. In order to explore the urbanization progress of China, the pape...
Article
Full-text available
Background An understanding of the factors driving the distribution of pathogens is useful in preventing disease. Often we achieve this understanding at a local microhabitat scale; however the larger scale processes are often neglected. This can result in misleading inferences about the distribution of the pathogen, inhibiting our ability to manage...
Article
Full-text available
Background The mode of transmission of the emerging neglected disease Buruli ulcer is unknown. Several potential transmission pathways have been proposed, such as amoebae, or transmission through food webs. Several lines of evidence have suggested that biting aquatic insects, Naucoridae and Belostomatidae, may act as vectors, however this proposal...
Article
Full-text available
Accurate cropland maps at the global and local scales are crucial for scientists, government and nongovernment agencies, farmers and other stakeholders, particularly in food-insecure regions, such as Sub-Saharan Africa. In this study, we aim to qualify the crop classes of the MODIS Land Cover Product (LCP) in Sub-Saharan Africa using FAO (Food and...
Article
Full-text available
From January 2002 to May 2012, 787 new BU cases were recorded in 154 villages of the district of Akonolinga. Incidence per village ranged from 0 (n = 59 villages) to 10.4 cases/1000 person.years (py); median incidence was 0.4 cases/1,000py. Villages neighbouring the Nyong River flood plain near Akonolinga town were identified as the highest risk zo...
Conference Paper
Full-text available
In West Africa, rainfall variability dynamics are often considered as the major driver of vegetation production. Land use shifts have also to be taken into account when analyzing changes in vegetation production. To study how land use changes may impact vegetation response along a climatic gradient, we used three MODIS NDVI metrics time series (200...
Article
Full-text available
Crop phenology is essential for evaluating crop production in the food insecure regions of West Africa. The aim of the paper is to study whether satellite observation of plant phenology are consistent with ground knowledge of crop cycles as expressed in agro-simulations. We used phenological variables from a MODIS Land Cover Dynamics (MCD12Q2) prod...
Article
Full-text available
Rift Valley fever (RVF) is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV) is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine t...
Article
Full-text available
We worked on the assumption that agricultural systems shaped the landscape through human cropping practices, and that the resulting landscape can be described with a set of coarse resolution satellite-derived metrics (spectral, textural, temporal, and spatial metrics). A Random Forest classification model was developed at the village scale in South...
Article
Land-cover changes occurring before 1800 are often ignored in the estimation of CO2 emissions, probably because they are poorly documented in most tropical countries. India appears to be an exception to this rule. It was possible to reconstitute the main stages of the land-cover history for a large region of South India, and therefore to retrace th...
Conference Paper
Full-text available
Crop phenology is essential information when evaluating crop production in the food insecure regions of West Africa. The only currently available global product that includes phenological variables is the MODIS Land Cover Dynamics Yearly (MCD12Q2) product. This product is produced each year at 500 m spatial resolution, from the 8-day vegetation ind...
Article
In Africa, food security early warning systems use satellite-derived data concerning crop conditions and agricultural production. Such systems can be improved if they are provided with a more reliable estimation of the cultivated area at national scale. This paper evaluates the potential of using time series from the MODerate resolution Imaging Spe...
Article
Full-text available
Modelling spatial dynamics may be used to gather understanding on how insect populations develop in a given environment. Hypotheses and independent knowledge inferred from ground observations can be confronted for consistency, and the mechanisms requiring finer descriptions can also be identified. Different scenarios of pest management can then be...
Article
The leaf area index (LAI) of fast-growing Eucalyptus plantations is highly dynamic both seasonally and inter-annually, and is spatially variable depending on pedo-climatic conditions. LAI is very important in determining the carbon and water balance of a stand, but is difficult to measure during a complete stand rotation and at large scales. Remote...
Article
Full-text available
In the Ferlo Region in Senegal, livestock depend on temporary ponds for water but are exposed to the Rift Valley Fever (RVF), a disease transmitted to herds by mosquitoes which develop in these ponds. Mosquito abundance is related to the emptying and filling phases of the ponds, and in order to study the epidemiology of RVF, pond modelling is requi...
Article
In this work, we consider that the modeling of complex domains can be performed using Domain Specific Languages (DSL). The main principle of this approach consists in developing DSL primitives and to assemble them to model a certain domain. The ability to add new primitives into an existing model and to fine-tune it by replacing some of them provid...
Article
Habitat loss and soil organic carbon (SOC) stock variations linked to land-cover change were estimated over two decades in the most densely populated biodiversity hotspot in the world, in order to assess the possible influence of conservation practices on the protection of SOC. For a study area of 88 484 km2, 70% of which lie inside the Western Gha...
Article
By allowing the estimation of forest structural and biophysical characteristics at different temporal and spatial scales, remote sensing may contribute to our understanding and monitoring of planted forests. Here, we studied 9-year time-series of the Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiomete...
Article
Full-text available
Recent studies have highlighted the potential role of water in the transmission of avian influenza (AI) viruses and the existence of often interacting variables that determine the survival rate of these viruses in water; the two main variables are temperature and salinity.Remote sensing has been used to map and monitor water bodies for several deca...
Article
Full-text available
Vegetated coastal ecosystems provide goods and services to billions of people. In the aftermath of a series of recent natural disasters, including the Indian Ocean Tsunami, Hurricane Katrina and Cyclone Nargis, coastal vegetation has been widely promoted for the purpose of reducing the impact of large storm surges and tsunami. In this paper, we rev...
Article
Full-text available
A hydrologic pond model was developed that simulates daily spatial and temporal variations (area, volume and height) of temporary ponds around Barkedji, a village located in the Ferlo Region in Senegal. The model was tested with rainfall input data from a meteorological station and from Tropical Rainfall Measuring Mission (TRMM) satellites. During...
Article
The modelling of processes that occur in landscapes is often confronted to issues related to the representation of space and the difficulty of properly handling time and multiple scales. In order to investigate these issues, a flexible modelling environment is required. We propose to develop such a tool based on a Domain Specific Language (DSL) tha...
Conference Paper
Full-text available
With modeling and simulation, it is possible to study how a system works before trying to predict how it would be-have in a variety of situations. However, when modeling landscape processes, issues related to space, time and mul-tiple scales need to be addressed. In order to investigate these issues, a modeling platform based on a Domain Specific L...
Article
Remote sensing methods for locating and monitoring temporary ponds over large areas in arid lands were tested on a study site in Northern Senegal. Three main results are presented, validated with field data and intended to highlight different spectral, spatial and temporal characteristics of the methods: (1) Among several water indices tested, two...
Article
Pedotransfer functions (PTFs) are used to estimate certain soil properties that are difficult and costly to measure front others more easily available. Bulk density is one important soil property. Although nor requiring complex analysis, its measurement remains time consuming and is lacking in many soil surveys. For several decades, PTFs have been...
Conference Paper
To predict and respond to famine and other forms of food insecurity, different early warning systems are using remote analyses of crop condition and agricultural production, using satellite-based information. To improve these predictions, a reliable estimation of the cultivated area at national scale must be carried out. In this study, we develop a...
Article
Full-text available
Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosqu...