Analsysis of ASTER GDEM elevation models

Digital elevation models (DEM) are of fundamental importance for remote sensing. With a DEM the three-dimensional positioning, requiring a stereo model can be reduced to a two-dimensional solution just based on a single image. With the free of charge availability of the SRTM-height models, covering the land area from 56 degrees southern up to 60.25 degrees northern latitude a nearly world wide coverage is given. But especially in mountainous regions and dry sand deserts the original SRTM DEMs have gaps in the original SRTM data. Now with the also free of charge available ASTER GDEM the area from 83 degrees southern up to 83 degrees northern latitude is covered. For areas where both height models exist, it is the question which height model should be preferred. Outside the USA the SRTM height data have a spacing of 3 arcsec (nearly 90m), while the ASTER GDEM has a spacing of just 1 arcsec (nearly 30m). The decision for the selection of the DEM is based on accuracy, homogeneity, reliability, completeness and morphologic details. In test areas with precise reference height models, located in the USA, Germany, France, Poland, Turkey and Jordan and with different morphology as mountainous, rolling, flat and urban and also with different land classes, the ASTER GDEM has been analyzed and compared with SRTM DEM as well as with SPOT 5 HRS and Cartosat 1 height models. ASTER GDEM in most cases shows improved accuracy with a higher number of number of stacks (number of images used for overlapping height models). But the accuracy improvement with more stacks is smaller as it should be for random data. The number of used stacks per DEM-point varies strongly depending upon the area. Especially in areas with low cloud coverage and higher imaging priority a high number of stacks have been used opposite to areas often covered by clouds and having lower imaging priority, where the dominating number of DEM-points may be located only in 2 stacks. Based on own matching results with ASTER images quite more morphologic details have been expected in ASTER GDEM having 1 arcsec point spacing as in SRTM height models with 3 arcsec spacing, but the analyzed data show only slightly more morphologic details as the SRTM 3" height model. SRTM as well as ASTER height models are strongly depending upon the morphology and the land coverage, so not a homogenous accuracy can be expected. In addition, as all height models, the accuracy depends usually linear upon the tangent of terrain slope, so the standard deviation of height (SZ) should be given in the form SZ = a + b*tan(terrain slope). Not only the standard deviation is important, the height models have different systematic errors (bias). The bias in X, Y and Z is larger for ASTER GDEM as for SRTM DEMs. Horizontal shifts have been determined by adjustment of the ASTER GDEMs against the reference height model. In general the SRTM height models are slightly more accurate as the ASTER GDEM

The Environmental Contribution to Wayfinding in Museums: Enhancement and Usage by Controlling Flows and Paths

The field of research in which wayfinding is situated refers to the way people move in reaction to environmental stimulation. It therefore fully concerns not just signage but also space designing, its geometric configuration, technical solutions and their material characterization. The focus is consequently on environmental factors that facilitate wayfinding in a museum (accessibility, visibility, etc.) and on other elements such as spatial configuration, architectural features and functional aspects. These factors influence relational phenomena and therefore visitors’ satisfaction. Methods and tools for designing and managing spaces have been studied in the research. The configurational analysis method of space has been used to objectify syntactic features of space. In particular, the outcomes of an experimental project, which have been analyzed in a master’s thesis on the re-functionalization of the museum of Palazzo dei Diamanti in Ferrara, are presented. Permeability, proximity, connections of spaces, namely meaningful features to ensure wayfinding have been examined. Space parameters resulting from the geometry of the layout, from the visual connections and from the changes of direction were then evaluated. The outcomes have been used as inputs for designing a unitary tour route circuit, that also reconnects the museum’s second floor, and for planning three independent alternative routes for a differentiated use of the museum

Efeitos da competição de plantas daninhas na cultura do sorgo granífero Sorghum bicolor (L.) Moench.

O trabalho foi realizado com o objetivo de se avaliar o efeitos da competicao de plantas daninhas sobre a cultura do sorgo granifero. O experimento foi conduzido no Centro Nacional de Pesquisa de Milho e Sorgo, em Sete Lagoas - MG, no ano agricola de 1983/84, utilizando-se o hibrido BR 300. A cultura conviveu com a populacao daninha durante duas semanas sem que sua producao fosse reduzida significativamente, mas um aumento no periodo de competicao a partir da quarta semana apos a emergencia da cultura, provocou uma reducao de paniculas por hectare, producao de graos por panicula e producao de graos por hectare

Generationing development

The articles in this special issue present a persuasive case for accounts of development to recognise the integral and fundamental roles played by age and generation. While the past two decades have witnessed a burgeoning of literature demonstrating that children and youth are impacted by development, and that they can and do participate in development, the literature has tended to portray young people as a special group whose perspectives should not be forgotten. By contrast, the articles collected here make the case that age and generation, as relational constructs, cannot be ignored. Appropriating the term ‘generationing’, the editors argue that a variety of types of age relations profoundly structure the ways in which societies are transformed through development – both immanent processes of neoliberal modernisation and the interventions of development agencies that both respond and contribute to these. Drawing on the seven empirical articles, I attempt to draw some of the ideas together into a narrative that further argues the case for ‘generationing’ but also identifies gaps, questions and implications for further research

Analysis and bias improvement of height models based on satellite images

Height models are a fundamental part of the geo-information required for various applications. The determination of height models by aerial photogrammetry, LiDAR or space images is time-consuming and expensive. For height models with large area coverage, UAVs are not economic. The freely available height models ASTER GDEM-3, SRTM, AW3D30 and TDM90 can meet various requirements. With the exception of ASTER-GDEM-3, which cannot compete with the other, the digital surface models SRTM, AW3D30 and TDM90 are analyzed in detail for accuracy and morphology in 4 test sites using LiDAR reference DTMs. The accuracy figures root mean square error, standard deviation, NMAD and LE90 are compared as well as the accuracy dependence on the terrain inclination. The analysis uses a layer for the open areas, excluding forest and settlement areas. Remaining elements that do not belong to a DTM are filtered. Particular attention is paid to systematic errors. The InSAR height models SRTM and TDM90 have some accuracy and morphological restrictions in mountain and settlement areas. Even so, the direct sensor orientation of TDM90 is better than for the other. Optimal results in terms of accuracy and morphology were achieved with AW3D30 corrected by TDM90 for the local absolute height level. This correction reduces the bias and also the tilt of the height models compared to the reference LiDAR DTM

Finding a way: long-term care homes to support dementia

An ageing demographic has increased the number of people with dementia. Although dementia is commonly associated with memory loss, other early symptoms include difficulty with wayfinding. Dementia alters visuo-spatial perception and the processes used to interpret the physical environment. The role of the design of the physical environment for people with dementia has gained increased recognition. Despite this, design for dementia is often overlooked, focusing on issues relating to physical impairment. This paper presents the results of a PhD study and aims to examine the role of the design of the physical environment in supporting wayfinding for people with dementia living in long-term care settings in Northern Ireland. Mixed methods combined the observation of wayfinding walks and conversational style interviews to elicit perspectives and experiences of residents with dementia. The findings aim to promote well-being for those with dementia living in long-term care settings