Breaking new ground in mapping human settlements from space -The Global Urban Footprint-

Today 7.2 billion people inhabit the Earth and by 2050 this number will have risen to around nine billion, of which about 70 percent will be living in cities. Hence, it is essential to understand drivers, dynamics, and impacts of the human settlements development. A key component in this context is the availability of an up-to-date and spatially consistent map of the location and distribution of human settlements. It is here that the Global Urban Footprint (GUF) raster map can make a valuable contribution. The new global GUF binary settlement mask shows a so far unprecedented spatial resolution of 0.4 arcsec ($\sim12 m$) that provides - for the first time - a complete picture of the entirety of urban and rural settlements. The GUF has been derived by means of a fully automated processing framework - the Urban Footprint Processor (UFP) - that was used to analyze a global coverage of more than 180,000 TanDEM-X and TerraSAR-X radar images with 3m ground resolution collected in 2011-2012. Various quality assessment studies to determine the absolute GUF accuracy based on ground truth data on the one hand and the relative accuracies compared to established settlements maps on the other hand, clearly indicate the added value of the new global GUF layer, in particular with respect to the representation of rural settlement patterns. Generally, the GUF layer achieves an overall absolute accuracy of about 85\%, with observed minima around 65\% and maxima around 98 \%. The GUF will be provided open and free for any scientific use in the full resolution and for any non-profit (but also non-scientific) use in a generalized version of 2.8 arcsec ($\sim84m$). Therewith, the new GUF layer can be expected to break new ground with respect to the analysis of global urbanization and peri-urbanization patterns, population estimation or vulnerability assessment

The role of earth observation in an integrated deprived area mapping “system” for low-to-middle income countries

Urbanization in the global South has been accompanied by the proliferation of vast informal and marginalized urban areas that lack access to essential services and infrastructure. UN-Habitat estimates that close to a billion people currently live in these deprived and informal urban settlements, generally grouped under the term of urban slums. Two major knowledge gaps undermine the efforts to monitor progress towards the corresponding sustainable development goal (i.e., SDG 11—Sustainable Cities and Communities). First, the data available for cities worldwide is patchy and insufficient to differentiate between the diversity of urban areas with respect to their access to essential services and their specific infrastructure needs. Second, existing approaches used to map deprived areas (i.e., aggregated household data, Earth observation (EO), and community-driven data collection) are mostly siloed, and, individually, they often lack transferability and scalability and fail to include the opinions of different interest groups. In particular, EO-based-deprived area mapping approaches are mostly top-down, with very little attention given to ground information and interaction with urban communities and stakeholders. Existing top-down methods should be complemented with bottom-up approaches to produce routinely updated, accurate, and timely deprived area maps. In this review, we first assess the strengths and limitations of existing deprived area mapping methods. We then propose an Integrated Deprived Area Mapping System (IDeAMapS) framework that leverages the strengths of EO- and community-based approaches. The proposed framework offers a way forward to map deprived areas globally, routinely, and with maximum accuracy to support SDG 11 monitoring and the needs of different interest groups

Multi-level Feature Fusion-based CNN for Local Climate Zone Classification from Sentinel-2 Images: Benchmark Results on the So2Sat LCZ42 Dataset

As a unique classification scheme for urban forms and functions, the local climate zone (LCZ) system provides essential general information for any studies related to urban environments, especially on a large scale. Remote sensing data-based classification approaches are the key to large-scale mapping and monitoring of LCZs. The potential of deep learning-based approaches is not yet fully explored, even though advanced convolutional neural networks (CNNs) continue to push the frontiers for various computer vision tasks. One reason is that published studies are based on different datasets, usually at a regional scale, which makes it impossible to fairly and consistently compare the potential of different CNNs for real-world scenarios. This study is based on the big So2Sat LCZ42 benchmark dataset dedicated to LCZ classification. Using this dataset, we studied a range of CNNs of varying sizes. In addition, we proposed a CNN to classify LCZs from Sentinel-2 images, Sen2LCZ-Net. Using this base network, we propose fusing multi-level features using the extended Sen2LCZ-Net-MF. With this proposed simple network architecture and the highly competitive benchmark dataset, we obtain results that are better than those obtained by the state-of-the-art CNNs, while requiring less computation with fewer layers and parameters. Large-scale LCZ classification examples of completely unseen areas are presented, demonstrating the potential of our proposed Sen2LCZ-Net-MF as well as the So2Sat LCZ42 dataset. We also intensively investigated the influence of network depth and width and the effectiveness of the design choices made for Sen2LCZ-Net-MF. Our work will provide important baselines for future CNN-based algorithm developments for both LCZ classification and other urban land cover land use classification

Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study

This study explores the potential to enhance the reflectance of solar insolation by the human settlement and grassland components of the Earth's terrestrial surface as a climate change mitigation measure. Preliminary estimates derived using a static radiative transfer model indicate that such efforts could amplify the planetary albedo enough to offset the current global annual average level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30 percent or 0.76 W/m2. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. However, additional study is needed to confirm the estimates reported here and to assess the economic and environmental impacts of active land-surface albedo amplification as a climate change mitigation measure.Comment: 21 pages, 3 figures. In press with Mitigation and Adaptation Strategies for Global Change, Springer, N

Irrigation Management Information Network (IMIN) Keyword thesaurus

Irrigation management / Thesauri / Information services / Networks

The application and effectiveness of remote sensing and geographical information systems for mapping and monitoring land use and land cover changes for development planning in UMnini Trust Traditional Council, eThekwini Municipality.

Masters Degree. University of KwaZulu-Natal, Durban.In the second half of the 21st century, developing countries experienced rapid population growth, which tended to settle in peri-urban areas of the cities because of limited spaces in the urban core areas and high urban land values. This movement into the outskirts of the cities has promoted peri-urban densification or urban sprawl/growth where the population become desperate for land and resides in close proximity to railway and road corridors, and environmentally sensitive areas etc. This rapid periurban densification decreased the availability of agricultural potential land and created a huge demand for social services delivery from municipalities. Therefore, municipalities need current and accurate information about trends of growth and development in a specific geographic area to determine the amount of social services need to be provided, which is significant for their development plans. Moreover, for accurate and up-to-date information and trends of growth analysis, South African municipalities rely on the techniques and tools such as aerial photographs and sample surveys, which are often inadequate to provide real time and accurate information on a regular basis, as these techniques collect this kind of information on a yearly basis while the population grows on a daily basis in developing worlds. The aim of this study was to assess the application and effectiveness of remote sensing (RS) and geographical information systems (GIS) for mapping and monitoring land use and land cover changes (LULCC) trends for development planning in uMnini Trust traditional council between 2001 and 2016. This time period has been chosen to align the study with the 15 years after eThekwini Metropolitan municipality was created in 2000, it was important to monitor and map the extent of growth in peri-urban areas of the metropolitan, which are the result of urban sprawl where people are situated in close proximity to urban core areas in search for economic opportunities. This study was guided by objectives, which are as follows; to determine the current LULCC planning and assessment processes used by municipality in uMnini Trust traditional council, to critically analyse the extent to which remote sensing and GIS have been used for sustainable land use planning and management; to identify different land use and land cover types found in uMnini Trust traditional council between 2001 and 2016, and analyse/categorise the changes that has occurred during the study period, in order to be able to analyse the rate and magnitude at which the peri-urban densification has been occurring in the study area which has a direct influence over the required infrastructure and social services. Lastly, to analyse challenges and constraints of using remote sensing and GIS for mapping and monitoring land use and land cover changes in uMnini Trust traditional council. This study adopted mixed (qualitative and quantitative) research methods. This combination of methods was employed in this study in order to provide a better understanding of research problems than either approach. Cognitive fit theory, sustainable development theory, and unified theory of acceptance and use of technology model were the theoretical bases for this study. Rapid peri-urban densification has contributed to land use changes, and also often led to rapid consumption of green or environmentally sensitive areas. Unregulated growth and development in urban areas has also resulted in the saturation of urban core areas, which increasing demand for land for development at the outskirts of the urban areas. Cognitive fit theory states that the use of geospatial technologies such as remote sensing and GIS, when the user possess relevant skills and expertise this yield good results that could help to come up with possible solution to assist in decision making process. Sustainable development theory advocates that there should be a development to satisfy the needs for the present generation, however, it must balance triple bottom line which include the social, economic, and environmental protection in ensuring that the needs of the future generations will be met. The unified theory of acceptance and technology model emerged because there was a need for the establishment of advanced technological innovations and application that have positive impacts on human and work life. This encouraged the organizations and governments to adopt the use of information technology in solving complex spatial related problems such as incompatible land uses. The results of this study revealed that there has been a gradual decline of agricultural potential areas in uMnini Trust traditional council within the study period. Rapid peri-urban densification has contributed and continues to contribute to rapid LULCC in the study area. It has been noted that this growth has implications on the provision of infrastructure and service delivery, as these people are increasing on a weekly or monthly basis which make it difficult for the municiplaity to have real time and accurate information about rate, trend, and magnitude of LULCC for their development plans. Integration of remote sensing and GIS in this study has demonstrated that this approach could be effective in providing LULCC in short period of time, which has been the shortcoming of the traditional planning tools

Assessment of environmental impact of gemstone mining in Ijero-Ekiti, Nigeria

Purpose. To examine the environmental impacts of gemstone mining activities on the people of Ijero-Ekiti, Ekiti State, Nigeria. Methods. Soil and water test were carried out on samples from the mine and its environment. Remote sensing as a tool for environmental assessment was introduced to generate the Normalized Difference Vegetation Index (NDVI) and Land Use Land Cover maps using ArcGIS 10 software. Findings. Water test carried out on stream, well and pond shows that some of the samples are slightly acidic. Total Dissolved Solid and hardness analysis show ranges lower than the acceptable limit given by Nigerian Industrial Standard and the World Health Organization (WHO). Iron concentration was found to be exceptionally higher than the permissible standard given by the WHO rendering the water resources unfit for drinking. Soil test carried out in the area proved that the soil is good for agriculture as it is high in nitrogen and organic matter content. Originality. This assertion can be back up by the results of the NDVI analysis which shows an increase in vegetation index from 0.2190 in the year of 1991 to 0.2435 in the year of 2013. Land use change detection analysis also showed a slight change in land use over the year from 2005 to 2010. This may be attributed to the fact that the gemstone mining is conducted on a small scale. Practical implications. Test results can be used in making recommendations to the community. Farmers cultivating land where samples S1 and S4 were taken need to apply fertilizer to bring up the percentage of organic matter of the soil. Provision of drinkable water sources should be made to the community. Remote sensing as the applied tool has proved its usefulness in environmental degradation assessing. It gives the possibility of generating an environmental database for impact assessment in regional context which can be a difficult task when carried out by the conventional method.Мета. Вивчити вплив на навколишнє середовище і жителів Іжеро-Екіті (штат Екіті, Нігерія) розробки родовищ дорогоцінного каміння. Методика. Для проведення досліджень проведено відбір проб ґрунтів і води з прилеглої місцевості шахти. Застосовано дистанційне зондування в якості інструменту екологічної оцінки для визначення нормалізованого відносного індексу рослинності (НВІР), а також карти землекористування й рослинного покриву за допомогою програмного забезпечення ArcGIS 10. Результати. Встановлено, що взяті у діючій свердловині та ставку-відстійнику зразки води є слабокислотними. Повний аналіз розчиненої твердої речовини й аналіз на жорсткість води показали менший розкид величин, ніж допустима межа, що визначена галузевим стандартом Нігерії та Всесвітньої організацій охорони здоров’я (ВООЗ), а рівень концентрації заліза значно вище допустимих меж, визначених ВООЗ для водних ресурсів, непридатних для пиття. Аналіз ґрунту в цьому районі підтвердив, що він придатний для сільського господарства, оскільки містить багато азоту й органічної речовини. Наукова новизна. За результатами аналізу НОІР спостерігається зростання вегетативного індексу з 0.2190 у 1991 році до 0.2435 у 2013 році. Аналіз визначення змін у землекористуванні також показав незначне річне різноманіття протягом року з 2005 до 2010. Це пояснюється тим фактом, що видобуток дорогоцінного каміння ведеться в невеликих масштабах. Практична значимість. Результати аналізів якості ґрунтів і води в районі видобутку можна використовувати при складанні рекомендацій для місцевого населення. Для підвищення продуктивності аграрного сектора в районі, де були взяті проби S1 і S4, слід застосовувати добриво, аби збільшити процентний вміст органічної речовини у ґрунті. Дистанційне зондування довело свою ефективність для оцінки погіршення екологічноїЦель. Изучить воздействие на окружающую среду и жителей Ижеро-Экити (штат Экити, Нигерия) разработки месторождений драгоценных камней. Методика. Для проведения исследований произведен отбор проб почв и воды из окрестностей шахты. Применено дистанционное зондирование в качестве инструмента экологической оценки для определения нормализованного относительного индекса растительности (НОИР), а также карты землепользования и растительного покрова посредством программного обеспечения ArcGIS 10. Результаты. Установлено, что взятые в действующей скважине и пруде-отстойнике образцы воды являются слабокислотными. Полный анализ растворенного твердого вещества и анализ на жесткость воды показали меньший разброс величин, чем допустимый предел, определенный отраслевым стандартом Нигерии и Всемирной организаций здравоохранения (ВОЗ), а уровень концентрации железа значительно выше приемлемых пределов, определенных ВОЗ для водных ресурсов, непригодных для питья. Анализ почвы в этом районе подтвердил, что она пригодна для сельского хозяйства, поскольку содержит много азота и органического вещества. Научная новизна. По результатам анализа НОИР наблюдается рост вегетативного индекса с 0.2190 в 1991 году до 0.2435 в 2013 году. Анализ определения изменений в землепользовании также показал незначительное годовое разнообразие на протяжении года с 2005 до 2010. Это объясняется тем фактом, что добыча драгоценных камней ведется в небольших масштабах. Практическая значимость. Результаты анализов качества почв и воды в районе добычи можно использовать при составлении рекомендаций для местного населения. Для повышения продуктивности аграрного сектора в районе, где были взяты пробы S1 и S4, следует применять удобрение, чтобы увеличить процентное содержание органического вещества в почве. Дистанционное зондирование доказало свою эффективность для оценки ухудшения экологической ситуации. Это дает возможность создания базы данных региональной оценки состояния окружающей среды, что весьма затруднительно при использовании традиционной методики.This research is sponsored by FUTA 003/15 project. The authors appreciate their contribution toward the success of the work. Input of the National Space Research and Development Agency (NASRDA) is also appreciated