scholarly journals Metric Accuracy of Digital Elevation Models from WorldView-3 Stereo-Pairs in Urban Areas

2019 ◽  
Vol 11 (7) ◽  
pp. 878 ◽  
Author(s):  
Emanuele Mandanici ◽  
Valentina A. Girelli ◽  
Luca Poluzzi

WorldView-3 satellite is providing images with an unprecedented combination of high spatial and spectral resolution. The stereo capabilities and the very high resolution of the panchromatic band (0.31 m) have been fostering new applications in urban areas, where the complexity of the morphology requires a higher level of detail. The present technical note aims to test the accuracy of digital elevation models that can be obtained by WorldView-3 stereo-pairs in these particular contexts, with an operational state-of-the-art algorithm. Validation is performed using check points and existing models of the area (from LiDAR data and oblique aerial images). The experiments, conducted over the city of Bologna (Italy) with six images, proved that roof surfaces and open spaces can be reconstructed with an average error of 1–2 pixels, but severe discrepancies frequently occur in narrow roads and urban canyons (up to several metres in average). The level of completeness achievable with only one pair is extremely variable (ranging from 50% to 90%), due to the combined effect of the geometry of acquisition and the specific urban texture. Better results can be obtained by using more than one pair. Furthermore, smaller convergence angles can be beneficial for the reconstruction of specific urban structures, such as soaring towers.

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Natalya Krutskikh

Abstract The study of internal and external factors in the formation of an urban geosystem is determined by its complex structure and multiple connections. Based on geoinformation modelling, an analysis of the landscape structure of the city territory is carried out, which can be a basis for further geoecological research. Morphometric indicators, which make it possible to determine the elementary geochemical landscapes, are indicated according to the data of the digital elevation model. A standardised topographic position index (TPI) is used to determine locations. Spatial zoning according to the type of land use reflects the qualitative features of the external load and technogenic impact. The data on the composition of the lithogenic base show the properties of the depositing medium and determine the natural background. Number of categories of landscapes identified are 58, characterised by a homogeneous geological composition, technogenic load and conditions for the migration of matter. The ratios of various landscape zones have been calculated. The study area as a whole is characterised by the predominance of migration processes over accumulation.


2016 ◽  
Vol 26 (1) ◽  
pp. 136
Author(s):  
Felipe Silva Guimarães ◽  
Lucas Da Silva Guimarães

<p>O estudo foi realizado no município de Rio Acima, localizado ao sul da região metropolitana de Belo Horizonte - MG. Na primeira etapa, foi feita a determinação das áreas de preservação permanente (APPs) do município, segundo a Lei 12.651 e a resolução CONAMA 303/2002 (esta última para delimitar as APPs de topo de morro), utilizando cinco bases topográficas distintas: vetorização de cartas do IBGE na escala de 1:50.000, imagem SRTM, Topodata, ASTER V2 e uma base vetorial disponibilizada pelo Codemig com curvas de nível equidistantes em 10 metros. Na segunda etapa, foram calculadas as áreas de cada uma das classes de APP resultantes dos mapeamentos feitos a partir de todas as bases e, em seguida, estes valores foram comparados. Ao final, foi observado que os resultados obtidos a partir da base do IBGE e da imagem ASTER V2 são os que apresentam característica mais restritiva, ou seja, com maiores áreas de preservação. Por outro lado, o mapa de áreas de preservação permanente confeccionado a partir da imagem SRTM foi o que apresentou caráter menos restritivo. Neste estudo também são discutidas outras diferenças entre os mapas elaborados a partir das cinco bases. </p><p> </p><p><strong>Palavras–chave:</strong> Município de Rio Acima, áreas de preservação permanente, modelos digitais de elevação, resolução espacial.</p><p><strong> </strong></p><p><strong> </strong></p><p><strong>Abstract </strong></p><p>This study was conducted in the municipality of Rio Acima (Minas Gerais State) located in the southern Belo Horizonte metropolitan region. In the first stage five different topographic bases were used to lay down the city permanent preservation areas (PPA) according to the Law 12,651 and CONAMA resolution 303/2002 (the latter to delimit the hilltop’s PPAs PPAs). These bases are the following: the vector at a 1:50.000 scale provided by the Brazilian Institute of Geography and Statistics (IBGE), SRTM image, image provided by INPE Topodata project, ASTER V2 Image and a vector base released by Codemig with 10 meters contour distance. In the second stage the areas of each one PPA classes were calculated resulting from all mapping bases. Then these values were compared. Finally it was observed that the results obtained from the ASTER V2 image and IBGE base are those with more restrictive features or in other words the result with lager PPAs. Moreover, the map of permanent preservation areas made from SRTM image showed the least restrictive character. This study also discusses other differences between the maps drawn from the five bases.</p><p><strong> </strong></p><p><strong>Keywords</strong>: Rio Acima municipality, permanent preservation areas, digital elevation models,   spacial resolution.</p>


2021 ◽  
Vol 29 (1) ◽  
pp. 71-86
Author(s):  
Gabriel Kopáčik ◽  
Antonín Vaishar ◽  
Eva Šimara

Abstract Analyses of the changes in the presence of persons in different central and residential parts of urban areas are subject to evaluation in this paper. Case studies of the cities of Brno, Ostrava and Zlín during the day and night are highlighted. Data from a provider of mobile phone services were used for the analyses. It appears that the data can be important for the comparison of different urban structures. The results demonstrate that the organisation of urban structure affects the number of visitors and thus the area attractiveness. It was confirmed that the number of mobile phone users in the city cores is higher than the number of permanent residents. The greatest differences between the day and night in the city cores were found in Brno, a concentric city with the most important central functions among the cities studied. Differences between the day and night in residential areas were not as large as expected. City neighbourhoods in Brno showed some specific rhythmicity.


2021 ◽  
Vol 7 (2) ◽  
pp. 106-115
Author(s):  
Wildani Pingkan Suripurna Hamzens ◽  
Meidy Widayanto Moestopo

Agribusiness may potentially develop on Palu Riversides. This research aims to formulate a sustainable agricultural spatial innovation for the Development of Agribusiness Places on Palu Riversides. The methods used for this study were field observation, satellite image map observation, and literature review. The results showed that the implementation of sustainable agriculture through the development of agribusiness places in urban areas could take advantage of the open spaces designated as green open space zone on the Palu Riversides, namely the River Green Area which is outside the riparian zone, the river overflow runoff area. To achieve this objective, it requires ability to innovate in spatial planning so that an urban agricultural area that is neatly arranged into an agribusiness places can also be developed into one of the city landmark.


2016 ◽  
Vol 9 (2) ◽  
pp. 169 ◽  
Author(s):  
Elena Lacilla ◽  
Jose Maria Ordeig

<p>The renovation of the waterfronts, such as those in the main public spaces of large cities, started in 1970s. Core industries had found other places to develop far from the city; thereafter key areas fell out of use and into disrepair. As a consequence, a huge number of urban areas became in urgent need of renewal. However, urban design guidelines to regenerate these open spaces have significantly changed since then. The approach towards returning these parts of the city to its inhabitants has evolved from an emphasis on building new housing in the nineties, to considering the broader aspects of sustainability in the early years of the current century and finally to searching for the areas’ identity in more recent years. Therefore, currently this identity is one of the main aspects designers are looking for. At the same time, the sustainability of the waterfront areas may be achieved through the establishment of this place´s sense of identity. In order to do this, we assess three urban actions undertaken in Portland and Vancouver -False Creek North, South Waterfront and Southeast False Creek-. The article suggests that the interplay between urban design, sustainability and identity is becoming the new driver for the design of the waterfronts.</p>


Cassowary ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 147-161
Author(s):  
Marlina Rumiris ◽  
Roni Bawole ◽  
Thomas Pattiasina

In general, the presence of green open space as one element in the urban spatial is very weak and the potencial is reduced portion because they do not have a high economic value. One function of green open space is for micro-climate amelioration, making green open space as a lugs of the city for helping the formation of a cool and comfortable climate in the vicinity. This comfort is determined by the interdependence between the factors of air temperature, air humidity, light and wind movement. Vegetation can improve the quality of the local climate or reducing temperature named micro-climate amelioration function as well. This study aimed to evaluate and redesign the typology of green open space to create green resolution with conversion of carbon to compansate for changes in the landscape that occur as a result of ongoing development. The study was conducted in urban areas of West Papua Province with five cases were selected purposively. Refers to the Ministry of Public Work No. 5 of 2008 and some related references, the results of research (qualitative exploration research) showed that 3 of the 5 cases have not met the ideal typology of Green Open Spaces, while two other cases have met the ideal typology for ecological function, but remain in need of the final material. Redesigns of Green Open Spaces that has been generated from this study are expected to restore ecological functions with holding the ecologycal aspect as a priority matter to consider as well. Therefor those can be used by local goverments for planning repairs or improvements in the future.


2018 ◽  
Vol 14 ◽  
pp. 1-14
Author(s):  
Ayasha Siddiqua

The geographical location of Bangladesh is gifted with enormous natural recourse: water, alluvial land,suitable climatic conditions for bio diversity and other natural assets. The capital, Dhaka, surroundedby rivers on four sides, was once a blue-green-built environment offering a healthy living atmosphere forits habitants. The city was dotted with huge and crisscrossed water bodies, a tolerable population density,and enough open spaces. Urban and peri-urban areas of the city complemented its food demand whichsubsequently maintained the environmental equilibrium. The modern concept of eco-urban-agriculture willdefinitely be beneficial in such a dense city which is rapidly losing its livability by insensitive urbanization.This paper will describe how a city could generate food, improve health, and utilize waste by furthering theestablished urban-agriculture concept. It aims to develop an understanding of this concept in Bangladesh,particularly in the dense urban fabric of Dhaka, by discussing the theoretical background of urban agricultureand practiced models of eco-urban-agriculture in urban settings around the world.


Author(s):  
F. Enßle ◽  
A. Fritz ◽  
B. Koch

Digital elevation models (DEMs) and height measurements are broadly used in environmental studies. Two common elevation sources are the Ice Cloud and land elevation Satellite (ICESat), which acquired laser range measurements with the Geoscience Laser Altimeter System (GLAS) across the globe and elevation data from the Shuttle Radar Topography Mission (SRTM). Current developments of small unmanned aerial vehicles (UAV) provide the opportunity to collect aerial images of remote areas at a high spatial resolution. These can be further processed to digital surface models by stereophotogrammetry and provide a reliable data source to evaluate coarse scale Digital Elevation Models (DEMs). <br><br> This study compares ICESat/GLAS and SRTM90 elevation data against photogrammetric terrain heights within GLAS footprints on high altitudes on the East Tibetan Plateau. Without vegetation-bias, we were able to examine height differences under different topographic conditions and of different acquisition dates. Several resampling techniques were applied to SRTM90 data and averaged height within each footprint was calculated. ICESat/GLAS heights (n = 148) are most similar to UAV data based elevations with an averaged difference of &minus;0.8m ±3.1m. Results furthermore indicate the validity of ICESat/GLAS heights, which are usually removed from analyses by applying different quality flags. Smallest difference of SRTM90 to UAV based heights could be observed by a natural neighbour resampling technique (averaged 3.6m ±14m), whereat other techniques achieved quite similar results. It can be confirmed that within a range of 3,800&ndash;4,200m above mean sea level the ICESat/GLAS heights are a precise source to determine elevation at footprint geolocation.


2019 ◽  
Vol 8 (1) ◽  
pp. 425
Author(s):  
Elif Bayramoğlu ◽  
Nazlı Mine Yurdakul

<p><strong>Abstract</strong></p><p>The rate of technological improvements, scientific activities and post-urbanization has increased rapidly, which has affected urban users. By creating an integral part of the city's environment, the use of active green areas enables the community to realize all sorts of social activities. City users prefer open public spaces in urban squares to perform recreational activities (relaxation, rest, eating and having a good time). Urban areas, which are mostly used by the users during the urbanization period, are the squares and the connected roads. The streets providing the plazas and transportation are the cultural heritage bearers of urban life as well as the memories that a city has accumulated over the years. The squares also have the effect of creating an image of the city reflecting its identity. As part of life in urban squares and streets, people are engaged in activities both physically and socially. However, these areas are occupied with heavy traffic and surrounded by the buildings at the point we are nowadays. For this reason, contemporary cities have begun to face contradictions as unidentified and unqualified compared to past cities. In this study, the city square and the connected Gazipaşa Street, Uzun Sokak, Maraş Street, which are described as the Trabzon Ataturk Field, were discussed in terms of square images, square functions, square functions and spatial structures. In this sense, the effects of the squares that differ from social, cultural and economical in terms of urban life, design and planning criteria have been evaluated. Observations and evaluations were carried out in the study. In this context, the quality of life of users has been evaluated and recommendations have been developed.</p><p><strong>Öz</strong></p><p>Teknolojik gelişmelerle bilimsel etkinlikler sonucu kentleşme oranı hızla artmış, bu durum kent kullanıcılarını etkilemiştir. Kent çevresiyle bir bütün oluşturarak aktif yeşil alan kullanımları ile toplumun her türlü sosyal aktiviteyi gerçekleştirebileceği olanaklara imkân sağlar. Kent kullanıcıları ise rekreatif (rahatlama, dinlenme, yemek yeme ve hoş vakit geçirme) etkinlikleri gerçekleştirmek için kent meydanlarındaki açık kamusal mekanları tercih ederler. Kentleşme süresi içerisinde kullanıcıların en yoğun kullandıkları kentsel alanlar meydanlar ve bağlantılı olan caddelerdir. Meydanlar ve ulaşımı sağlayan sokaklar bir kentin yıllar boyunca içinde biriktirdiği anıları ile kentsel yaşam noktası niteliğindeki kültürel bir miras taşıyıcılarıdır. Meydanlar aynı zamanda kimliğini yansıtarak kente imaj yaratma etkisi de vardır. Kent meydanları ve sokaklarda yaşamın bir parçası olarak insanlar fiziksel ve sosyal açıdan etkinliklerde bulunurlar. Ancak günümüzde geldiğimiz noktada bu alanlar yoğun trafik ile işgal edilerek binalarla kuşatılmıştır. Bu nedenle geçmiş kentlerine oranla günümüz kentleri kimliksiz ve niteliksiz olarak karşımıza çıkmaya başlamıştır. Bu çalışmada Trabzon Atatürk Alanı olarak nitelendirilen kent meydanı ve bağlantılı Gazipaşa Caddesi, Uzun Sokak, Maraş Caddesi’nde yapılar, meydan imgeleri, meydan işlev-fonksiyonları ve mekansal yapıları bakımından ele alınmıştır. Bu anlamda sosyal, kültürel ve ekonomik açıdan farklılık gösteren meydanların kent yaşamına olan etkileri, tasarım ve planlama kriterleri değerlendirilmiştir. Çalışmada gözlemler ve değerlendirmeler yapılmıştır. Bu kapsamda kullanıcıların yaşam kaliteleri değerlendirilerek öneriler geliştirilmiştir.</p>


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