291,233 research outputs found
From Urban Terrain Models to Visible Cities
We are now faced with the possibility and in some cases the results of acquiring accurate digital representations of our cities. But these cities will not be capable of interactive visualization unless we meet some fundamental challenges. The first challenge is to take data from multiple sources, which are often accurate in themselves but incomplete, and weave them together into comprehensive models. Because of the size and extent of the data that can now be obtained, this modeling task is daunting and must be accomplished in a semi-automated manner. Once we have comprehensive models, and especially if we can build them rapidly and extend them at will, the next question is what to do with them. Thus the second challenge is to make the models visible. In particular they must be made interactively visible so they can be explored, inspected, and analyzed.
In this article, we discuss the nature of the acquired urban data and how we are beginning to meet the challenges and produce visually navigable models. These models provide the basis for building virtual environments for a variety of applications
Map Generation from Large Scale Incomplete and Inaccurate Data Labels
Accurately and globally mapping human infrastructure is an important and
challenging task with applications in routing, regulation compliance
monitoring, and natural disaster response management etc.. In this paper we
present progress in developing an algorithmic pipeline and distributed compute
system that automates the process of map creation using high resolution aerial
images. Unlike previous studies, most of which use datasets that are available
only in a few cities across the world, we utilizes publicly available imagery
and map data, both of which cover the contiguous United States (CONUS). We
approach the technical challenge of inaccurate and incomplete training data
adopting state-of-the-art convolutional neural network architectures such as
the U-Net and the CycleGAN to incrementally generate maps with increasingly
more accurate and more complete labels of man-made infrastructure such as roads
and houses. Since scaling the mapping task to CONUS calls for parallelization,
we then adopted an asynchronous distributed stochastic parallel gradient
descent training scheme to distribute the computational workload onto a cluster
of GPUs with nearly linear speed-up.Comment: This paper is accepted by KDD 202
A Synergistic Approach for Recovering Occlusion-Free Textured 3D Maps of Urban Facades from Heterogeneous Cartographic Data
In this paper we present a practical approach for generating an
occlusion-free textured 3D map of urban facades by the synergistic use of
terrestrial images, 3D point clouds and area-based information. Particularly in
dense urban environments, the high presence of urban objects in front of the
facades causes significant difficulties for several stages in computational
building modeling. Major challenges lie on the one hand in extracting complete
3D facade quadrilateral delimitations and on the other hand in generating
occlusion-free facade textures. For these reasons, we describe a
straightforward approach for completing and recovering facade geometry and
textures by exploiting the data complementarity of terrestrial multi-source
imagery and area-based information
Fusion of Heterogeneous Earth Observation Data for the Classification of Local Climate Zones
This paper proposes a novel framework for fusing multi-temporal,
multispectral satellite images and OpenStreetMap (OSM) data for the
classification of local climate zones (LCZs). Feature stacking is the most
commonly-used method of data fusion but does not consider the heterogeneity of
multimodal optical images and OSM data, which becomes its main drawback. The
proposed framework processes two data sources separately and then combines them
at the model level through two fusion models (the landuse fusion model and
building fusion model), which aim to fuse optical images with landuse and
buildings layers of OSM data, respectively. In addition, a new approach to
detecting building incompleteness of OSM data is proposed. The proposed
framework was trained and tested using data from the 2017 IEEE GRSS Data Fusion
Contest, and further validated on one additional test set containing test
samples which are manually labeled in Munich and New York. Experimental results
have indicated that compared to the feature stacking-based baseline framework
the proposed framework is effective in fusing optical images with OSM data for
the classification of LCZs with high generalization capability on a large
scale. The classification accuracy of the proposed framework outperforms the
baseline framework by more than 6% and 2%, while testing on the test set of
2017 IEEE GRSS Data Fusion Contest and the additional test set, respectively.
In addition, the proposed framework is less sensitive to spectral diversities
of optical satellite images and thus achieves more stable classification
performance than state-of-the art frameworks.Comment: accepted by TGR
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