ISPRS International Journal of Geo-Information

383 KiB

Open AccessArticle

Spatial Relations Using High Level Concepts

by Padraig Corcoran, Peter Mooney and Michela Bertolotto

ISPRS Int. J. Geo-Inf. 2012, 1(3), 333-350; https://doi.org/10.3390/ijgi1030333 - 13 Dec 2012

Cited by 13 | Viewed by 8661

Existing models of spatial relations do not consider that different concepts exist on different levels in a hierarchy and in turn that the spatial relations in a given scene are a function of the specific concepts considered. One approach to determining the existence [...] Read more.

Existing models of spatial relations do not consider that different concepts exist on different levels in a hierarchy and in turn that the spatial relations in a given scene are a function of the specific concepts considered. One approach to determining the existence of a particular spatial relation is to compute the corresponding high level concepts explicitly using map generalization before inferring the existence of the spatial relation in question. We explore this idea through the development of a model of the spatial relation “enters” that may exist between a road and a housing estate. Full article

► Show Figures

Graphical abstract

866 KiB

Open AccessArticle

Towards Automatic Vandalism Detection in OpenStreetMap

by Pascal Neis, Marcus Goetz and Alexander Zipf

ISPRS Int. J. Geo-Inf. 2012, 1(3), 315-332; https://doi.org/10.3390/ijgi1030315 - 22 Nov 2012

Cited by 79 | Viewed by 19248

Abstract

The OpenStreetMap (OSM) project, a well-known source of freely available worldwide geodata collected by volunteers, has experienced a consistent increase in popularity in recent years. One of the main caveats that is closely related to this popularity increase is different types of vandalism [...] Read more.

The OpenStreetMap (OSM) project, a well-known source of freely available worldwide geodata collected by volunteers, has experienced a consistent increase in popularity in recent years. One of the main caveats that is closely related to this popularity increase is different types of vandalism that occur in the projects database. Since the applicability and reliability of crowd-sourced geodata, as well as the success of the whole community, are heavily affected by such cases of vandalism, it is essential to counteract those occurrences. The question, however, is: How can the OSM project protect itself against data vandalism? To be able to give a sophisticated answer to this question, different cases of vandalism in the OSM project have been analyzed in detail. Furthermore, the current OSM database and its contributions have been investigated by applying a variety of tests based on other Web 2.0 vandalism detection tools. The results gathered from these prior steps were used to develop a rule-based system for the automated detection of vandalism in OSM. The developed prototype provides useful information about the vandalism types and their impact on the OSM project data. Full article

► Show Figures

Graphical abstract

1088 KiB

Open AccessArticle

Geoprocessing Journey-to-Work Data: Delineating Commuting Regions in Dalarna, Sweden

by Martin Landré

ISPRS Int. J. Geo-Inf. 2012, 1(3), 294-314; https://doi.org/10.3390/ijgi1030294 - 14 Nov 2012

Cited by 9 | Viewed by 7358

Abstract

Delineation of commuting regions has always been based on statistical units, often municipalities or wards. However, using these units has certain disadvantages as their land areas differ considerably. Much information is lost in the larger spatial base units and distortions in self-containment values, [...] Read more.

Delineation of commuting regions has always been based on statistical units, often municipalities or wards. However, using these units has certain disadvantages as their land areas differ considerably. Much information is lost in the larger spatial base units and distortions in self-containment values, the main criterion in rule-based delineation procedures, occur. Alternatively, one can start from relatively small standard size units such as hexagons. In this way, much greater detail in spatial patterns is obtained. In this paper, regions are built by means of intrazonal maximization (Intramax) on the basis of hexagons. The use of geoprocessing tools, specifically developed for the processing of commuting data, speeds up processing time considerably. The results of the Intramax analysis are evaluated with travel-to-work area constraints, and comparisons are made with commuting fields, accessibility to employment, commuting flow density and network commuting flow size. From selected steps in the regionalization process, a hierarchy of nested commuting regions emerges, revealing the complexity of commuting patterns. Full article

► Show Figures

Graphical abstract

792 KiB

Open AccessArticle

A Spatial Multi-Criteria Model for the Evaluation of Land Redistribution Plans

by Demetris Demetriou, Linda See and John Stillwell

ISPRS Int. J. Geo-Inf. 2012, 1(3), 272-293; https://doi.org/10.3390/ijgi1030272 - 9 Nov 2012

Cited by 22 | Viewed by 7971

Abstract

A planning support system for land consolidation has been developed that has, at its heart, an expert system called LandSpaCES (Land Spatial Consolidation Expert System) which contains a “design module” that generates alternative land redistributions under different scenarios and an “evaluation module” which [...] Read more.

A planning support system for land consolidation has been developed that has, at its heart, an expert system called LandSpaCES (Land Spatial Consolidation Expert System) which contains a “design module” that generates alternative land redistributions under different scenarios and an “evaluation module” which integrates GIS with multi-criteria decision making for assessing these alternatives. This paper introduces the structural framework of the latter module which has been applied using a case study in Cyprus. Two new indices are introduced: the “parcel concentration coefficient” for measuring the dispersion of parcels; and the “landowner satisfaction rate” for predicting the acceptance of the land redistribution plan by the landowners in terms of the location of their new parcels. These two indices are used as criteria for the evaluation of the land redistribution alternatives and are transferable to any land consolidation project. Moreover, a modified version of the ratio estimation procedure, referred to as the “qualitative rating method” for assigning weights to the evaluation criteria, is presented, along with a set of non-linear value functions for standardizing the performance scores of the alternatives and incorporating expert knowledge for five evaluation criteria. The application of the module showed that it is a powerful new tool for the evaluation of alternative land redistribution plans that could be implemented in other countries after appropriate adjustments. A broader contribution has also been made to spatial planning processes, which might follow the methodology and innovations presented in this paper. Full article

► Show Figures

Figure 1

3667 KiB

Open AccessArticle

A Visual Analytics Approach for Extracting Spatio-Temporal Urban Mobility Information from Mobile Network Traffic

by Günther Sagl, Martin Loidl and Euro Beinat

ISPRS Int. J. Geo-Inf. 2012, 1(3), 256-271; https://doi.org/10.3390/ijgi1030256 - 2 Nov 2012

Cited by 43 | Viewed by 10665

Abstract

In this paper we present a visual analytics approach for deriving spatio-temporal patterns of collective human mobility from a vast mobile network traffic data set. More than 88 million movements between pairs of radio cells—so-called handovers—served as a proxy for more than two [...] Read more.

In this paper we present a visual analytics approach for deriving spatio-temporal patterns of collective human mobility from a vast mobile network traffic data set. More than 88 million movements between pairs of radio cells—so-called handovers—served as a proxy for more than two months of mobility within four urban test areas in Northern Italy. In contrast to previous work, our approach relies entirely on visualization and mapping techniques, implemented in several software applications. We purposefully avoid statistical or probabilistic modeling and, nonetheless, reveal characteristic and exceptional mobility patterns. The results show, for example, surprising similarities and symmetries amongst the total mobility and people flows between the test areas. Moreover, the exceptional patterns detected can be associated to real-world events such as soccer matches. We conclude that the visual analytics approach presented can shed new light on large-scale collective urban mobility behavior and thus helps to better understand the “pulse” of dynamic urban systems. Full article

► Show Figures

Figure 1

516 KiB

Open AccessArticle

Detecting Changes in Forest Structure over Time with Bi-Temporal Terrestrial Laser Scanning Data

by Xinlian Liang, Juha Hyyppä, Harri Kaartinen, Markus Holopainen and Timo Melkas

ISPRS Int. J. Geo-Inf. 2012, 1(3), 242-255; https://doi.org/10.3390/ijgi1030242 - 26 Oct 2012

Cited by 51 | Viewed by 10333

Abstract

Changes to stems caused by natural forces and timber harvesting constitute an essential input for many forestry-related applications and ecological studies, especially forestry inventories based on the use of permanent sample plots. Conventional field measurement is widely acknowledged as being time-consuming and labor-intensive. [...] Read more.

Changes to stems caused by natural forces and timber harvesting constitute an essential input for many forestry-related applications and ecological studies, especially forestry inventories based on the use of permanent sample plots. Conventional field measurement is widely acknowledged as being time-consuming and labor-intensive. More automated and efficient alternatives or supportive methods are needed. Terrestrial laser scanning (TLS) has been demonstrated to be a promising method in forestry field inventories. Nevertheless, the applicability of TLS in recording changes in the structure of forest plots has not been studied in detail. This paper presents a fully automated method for detecting changes in forest structure over time using bi-temporal TLS data. The developed method was tested on five densely populated forest plots including 137 trees and 50 harvested trees in point clouds. The present study demonstrated that 90 percent of tree stem changes could be automatically located from single-scan TLS data. These changes accounted for 92 percent of the changed basal area. The results indicate that the processing of TLS data collected at different times to detect tree stem changes can be fully automated. Full article

► Show Figures

Figure 1

2174 KiB

Open AccessArticle

Satellite Image Pansharpening Using a Hybrid Approach for Object-Based Image Analysis

by Brian Alan Johnson, Ryutaro Tateishi and Nguyen Thanh Hoan

ISPRS Int. J. Geo-Inf. 2012, 1(3), 228-241; https://doi.org/10.3390/ijgi1030228 - 16 Oct 2012

Cited by 32 | Viewed by 10176

Abstract

Intensity-Hue-Saturation (IHS), Brovey Transform (BT), and Smoothing-Filter-Based-Intensity Modulation (SFIM) algorithms were used to pansharpen GeoEye-1 imagery. The pansharpened images were then segmented in Berkeley Image Seg using a wide range of segmentation parameters, and the spatial and spectral accuracy of image segments was [...] Read more.

Intensity-Hue-Saturation (IHS), Brovey Transform (BT), and Smoothing-Filter-Based-Intensity Modulation (SFIM) algorithms were used to pansharpen GeoEye-1 imagery. The pansharpened images were then segmented in Berkeley Image Seg using a wide range of segmentation parameters, and the spatial and spectral accuracy of image segments was measured. We found that pansharpening algorithms that preserve more of the spatial information of the higher resolution panchromatic image band (i.e., IHS and BT) led to more spatially-accurate segmentations, while pansharpening algorithms that minimize the distortion of spectral information of the lower resolution multispectral image bands (i.e., SFIM) led to more spectrally-accurate image segments. Based on these findings, we developed a new IHS-SFIM combination approach, specifically for object-based image analysis (OBIA), which combined the better spatial information of IHS and the more accurate spectral information of SFIM to produce image segments with very high spatial and spectral accuracy. Full article

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

ISPRS Int. J. Geo-Inf., Volume 1, Issue 3 (December 2012) – 7 articles , Pages 228-350

Further Information

Guidelines

MDPI Initiatives

Follow MDPI