Rethinking the U-Net, ResUnet, and U-Net3+ architectures with dual skip connections for building footprint extraction

The importance of building footprints and their inventory has been recognised as foundational spatial information for multiple societal problems. Extracting complex urban buildings involves the segmentation of very high-resolution (VHR) earth observation (EO) images. U-Net is a common deep learning network and foundation for its new incarnations like ResUnet, U-Net++ and U-Net3+ for such segmentation. The re-incarnations look for efficiency gain by re-designing the skip connection component and exploiting the multi-scale features in U-Net. However, skip connections do not always improve these networks and context information is lost in the multi-scale features. In this paper, we propose three novel dual skip connection mechanisms for U-Net, ResUnet, and U-Net3+. This deepens the feature maps forwarded by the skip connections to find a more accurate trade-off between context and localisation within these networks. The mechanisms are evaluated on feature maps of different scales in the three networks, producing nine new network configurations. The networks are evaluated against their original vanilla versions using four building footprint datasets (three existing and one new) of different spatial resolutions: VHR (0.3m), high-resolution (1m and 1.2m), and multi-resolution (0.3+0.6+1.2m). The proposed mechanisms report efficiency gain on five evaluation measures for U-Net and ResUnet, and up to 17.7% and 18.4% gain in F1 score and Intersection over Union (IoU) for U-Net3+. The codes will be available in a GitHub link after peer review.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Spatially Enabled society

The term ‘spatially enabled society’ describes the emerging cultural and governance revolution offered by pervasive spatial information technologies and spatially equipped citizens. Spatially enabled societies make possible, amongst many other things, sustainable cities,early warning systems e.g. in relation to the global financial crisis, smarter delivery of housing, improved risk management, and better macroeconomic decision making. This article introduces the current international discussion around the evolving concept of ‘spatially enabled society’. The concept is not about managing spatial information - it is about managing information, or governing society, spatially

Spatially Enabled society

The term ‘spatially enabled society’ describes the emerging cultural and governance revolution offered by pervasive spatial information technologies and spatially equipped citizens. Spatially enabled societies make possible, amongst many other things, sustainable cities,early warning systems e.g. in relation to the global financial crisis, smarter delivery of housing, improved risk management, and better macroeconomic decision making. This article introduces the current international discussion around the evolving concept of ‘spatially enabled society’. The concept is not about managing spatial information - it is about managing information, or governing society, spatially

Investigating pedestrians’ obstacle avoidance behaviour

Modelling and simulating pedestrian motions are standard ways to investigate crowd dynamics aimed to enhance pedestrians’ safety. Movement of people is affected by interactions with one another and with the physical environment that it may be a worthy line of research. This paper studies the impact of speed on how pedestrians respond to the obstacles (i.e. Obstacles avoidance behaviour). A field experiment was performed in which a group of people were instructed to perform some obstacles avoidance tasks at two levels of normal and high speeds. Trajectories of the participants are extracted from the video recordings for the subsequent intentions:(i) to seek out the impact of total speed, x and yaxis (ii) to observe the impact of the speed on the movement direction, x-axis, (iii) to find out the impact of speed on the lateral direction, y-axis. The results of the experiments could be used to enhance the current pedestrian simulation models

Spatially Enabled society

The term ‘spatially enabled society’ describes the emerging cultural and governance revolution offered by pervasive spatial information technologies and spatially equipped citizens. Spatially enabled societies make possible, amongst many other things, sustainable cities,early warning systems e.g. in relation to the global financial crisis, smarter delivery of housing, improved risk management, and better macroeconomic decision making. This article introduces the current international discussion around the evolving concept of ‘spatially enabled society’. The concept is not about managing spatial information - it is about managing information, or governing society, spatially

Hierarchical Spatial Reasoning Applied to Spatial Data Infrastructures

Many countries throughout the world believe they can benefit both economically and environmentally from better management of their spatial data assets, enabling them to access and retrieve complete and consistent datasets in an easy and secure way. This has resulted in the development of the Spatial Data Infrastructure (SDI) concept at various political and/or administrative levels. The SDI concept has been represented by different descriptions of its nature, however, currently these demonstrate an overly-simplistic understanding of the concept. The simplicity in existing definitions has been slow to incorporate the concept of an integrated, multilevelled SDI formed from a hierarchy of inter-connected SDIs at corporate, local, state/provincial, national, regional (multi-national) and global (GSDI) levels. Failure to incorporate this multidimensionality, and the dynamic mechanistic and functional roles of the SDI have rendered many descriptions of SDI inadequate to describe the complexity and the dynamics of SDI as it develops,and thus ultimately constrain SDI achieving developmental potential in the future. As a result, the objective of this paper is to demonstrate the fitness and applicability of Hierarchical Spatial Reasoning (HSR) as a theoretical framework to demonstrate the multi-dimensional nature of SDIs. It is argued that by better understanding and demonstrating the nature of an SDI hierarchy, any SDI development can gain support from a wider community of both government and nongovernment data users and providers. The findings presented in this paper build on the authors experiences in Regional SDI (multi-national) development and HSR

Understanding land administration systems

This is a preprint of a paper from 14th PCGIAP Meeting (International Seminar on Land Administration Trends & Issues in Asia & The Pacific Region), 19-20 August 2008. http://www.csdila.unimelb.edu.au/projects/PCGIAPLASeminar/index.html.19-20 August 200

Seamless SDI Design by Using UML Modeling

The integration of marine and land based spatial information will support sustainable management and development of the coastal zone. Therefore, the development of a seamless platform covering the land and marine environments would facilitate more efficient and effective decision-making capabilities for any jurisdiction with land-marine interface. This paper discusses the potential for developing a seamless platform covering the land, marine and coastal environments as part of the National Spatial Data Infrastructure (SDI) enabling a more integrated and holistic approach to management of the land-marine interface. It addresses the feasibility of seamless platform towards spatially enabled society and government. Further, it provides an insight to the design and development of the Seamless SDI model by introducing Seamless SDI conceptual model. The Seamless SDI class and its inherited characteristics and properties will be discussed. In addition to the conceptual phase, the development of a Seamless SDI model also consists of two more stages: design phase and implementation phase. The Use Case Diagram and Class Diagram of the Enterprise Viewpoint will be developed. Finally, it highlights the importance of the creation of appropriate Seamless SDI governance structures that are both understood and accepted. This would help to develop an extended framework to support a spatially enabled jurisdiction covering the land-marine interface. Ideally this extended framework would result in harmonised and universal access, sharing and integration of coastal, marine and terrestrial spatial datasets across regions and disciplines

Leveraging VGI Integrated with 3D Spatial Technology to Support Urban Intensification in Melbourne, Australia

High density residential development in metropolitan Melbourne, where contradictory imperatives of neighbourhood character and urban intensification play important roles, remains an uncertain practice. One key issue for plan implementation is the lack of consistency between authorities, developers and the community in interpreting the standards, design guidelines, and state/local strategies, especially those relating to neighbourhood character. There is currently no mechanism to incorporate community perceptions and place experiences as subjective aspects of neighbourhood character in development assessments. There is also little use of micro-scale and multi-dimensional spatial analysis to integrate these subjective aspects with objective measures (e.g. building volume and height; streetscape) to communicate effectively—and in a limited timeframe—with all stakeholders. This paper explores the potential of two emerging geospatial technologies that can be leveraged to respond to these problems. Evidence in the literature suggests that volunteered geographic information (VGI) can provide community input around subjective aspects of the urban environment. In addition, a deluge of three-dimensional (3D) spatial information (e.g. 3D city models) is increasingly available for micro-level (building- or property-level) assessment of the physical aspects of the urban environment. This paper formulates and discusses a conceptual framework to link these two spatial technological advancements in a virtual geographic environment (VGE) that accounts for micro-scale 3D spatial analysis incorporating both subjective and objective aspects of neighbourhood character relevant in implementing compact city strategies