k-russell/x_sections_tool: Cross-sections and Dimensions [Software]

<p>Cross-sections and Dimensions tool v1.0</p> <p>A spatial tool for creation of stream cross-sections and delineation of bankfull extent based on slope threshold</p> <p><strong>Full Changelog</strong>: https://github.com/k-russell/x_sections_tool/commits/v1.0</p&gt

Spatial data integration for classification of 3D point clouds from digital photogrammetry

Under increased urban settlement density, access to a high resolution (land-parcel scale) bare-earth Digital Elevation Model (DEM) is a pre-requisite for much decision support for planning: stormwater assessment, flood control, 3D visualisation, automatic delineation of flow paths, sub watersheds and flow networks for hydrological modelling. In these terms, a range of options face the DEM-building team. Apart from using necessarily expensive field survey, or use of out-of-date terrain information (usually in the form of digital contours of less-than-satisfactory interval) the model will be built from point-clouds. These will have been assembled via digital photogrammetry or acquisition of LiDAR data. In the first instance, both these data types soon yield a model that is known as a digital surface model (DSM). It includes any buildings, vehicles, vegetation (canopy and understory), as well as the bare ground". To generate the required bare-earth' DEM, ground and non-ground features/data points must be distinguished from each other so that the latter can be eliminated before DEM building. Existing methods for doing this are based on data filtering routines, and are known to produce errors of omission and commission. Moreover, their implementation is complex and time consuming.I report here, the results of deploying spatial data integration instead of the previously favoured filtering routines. The challenge was to identify a process flow for separating the ground and non-ground points. It is shown that this alternative approach can be implemented if the client can supply a range of ancillary height data, this being most economically forthcoming if archivally available. The relative significance of these archival datasets emerges from exploring the various process flow paths and devising relevant quality tests designed to distinguish input suitable to support modelling at a land-parcel scale of analysis. Then the ArcGIS topological overlay technique was used to collect zonal statistics for each 3D point. Thus each output 3D point acquires z (elevation) values derived from the digital photogrammetry and z-statistics (minimum, maximum, mean) of its assigned zone. Clearly there is value in spatial data integration for a city with spatial data archives of adequately supportive scope and quality

Development of a Web-GIS based geotechnical information system

10.1061/(ASCE)0887-3801(2005)19:3(323)Journal of Computing in Civil Engineering193323-327JCCE

Towards automation of impervious surface mapping using high resolution orthophoto

Information on the amount and pattern of impervious surface is important for hydrological modelling of urban areas. As cities expand and/or develop, hydrologic models will become outdated unless information on impervious surfaces is kept up to date. At the moment, the mapping teams are faced with choosing from among a range of alternative approaches/tools/software products to achieve this. We report here, the results of experiments conducted for a range of mapping approaches applied to high resolution orthophoto imagery covering part of the residential zone of Monash City, a local government area in Melbourne, Victoria, Australia. The application of the Expert Classification (EC) or Feature Analyst (FA) approaches requires initial human involvement to set the knowledge/learner function, which, then can be applied to any areas of similar spectral patterns. The Feature Analyst (FA) approach yielded superior results compared these 'pixel-by-pixel' methods. All of these approaches refer to mapping in aid of distributed and connectivity modelling. In the absence of access to EC or FA tools, application of the (sampling-based) Precision Method (PM), (after careful consideration of sampling stratification) will offer total impervious surface data-input estimates for lumped hydrological modelling

A spatially explicit framework for climate adaptation

<p>Cities increasingly confront climate change-related problems of flooding, urban heat island effects, and the impact of drought on vegetation. There is a need for urban water and infrastructure planners to be able to identify vulnerable areas and to design, compare and evaluate interventions to address these problems. In response to this need, we developed the Integrated Climate Adaptation Model (ICAM), which is a Web-GIS tool based on a spatially explicit framework. ICAM has a user-friendly interface for use by a wide range of urban planning and design professionals. The tool is built on high-resolution spatial datasets, allowing users to identify critical areas that may be impacted by sea-level rise, drought, flooding, temperature increases and threats to tree heath and to consider the benefits of various grey and green infrastructure interventions. The tool is suitable for planning and evaluating interventions and to identify pathways for further desktop modelling.</p