GISTAM 2017 Abstracts


Conference

GISTAM 2017

Area 1 - Data Acquisition and Processing

Full Papers
Paper Nr: 11
Title:

A Generic, Extensible Data Model for Trajectory Determination Systems

Authors:

José A. Navarro and M. Eulàlia Parés

Abstract: Trajectory Determination Systems (TDS) use the measurements delivered by sensors to estimate trajectories. Many are the types of sensors that may be used already by such systems and new ones appear constantly in the market. Variety and fast change pace pose a problem for the maintenance of any kind of software system, including TDSs. Some data models and / or standards dealing with sensor data exist, but these are either too generic (and ambitious) or, on the contrary, targeted at very specific types of observations (as, for instance, GNSS.) This paper introduces a compact but complete, generic and extensible data model powerful enough as to deal with the kind of observations involved in trajectory determination and able to alleviate or even eliminate the software maintenance toll derived by constant changes in data sources. Two materialization of this data model, its file and network interfaces are briefly presented here as well as a portable C++ library implementing such interfaces.

Paper Nr: 34
Title:

Data Density Considerations for Crowd Sourced Population Estimations from Social Media

Authors:

Samuel Lee Toepke

Abstract: When using social media data for population estimations, data density is of primary concern. A high density of quality, crowd-sourced data in a specified geographic area leads to a more precise estimation. Nonetheless, data acquisition/storage has to be balanced against the provisioned cost/size constraints of the technical implementation and the ability to receive data in that area. This investigation compares hourly population estimations based on Tweet quantity, for several major west coast cities in the United States of America. An estimation baseline is established, and data is artificially removed from the estimation to explore the importance of data density. Experimental data is obtained and stored using an enterprise cloud solution, density observations/results are discussed, and follow-on work is described.

Paper Nr: 63
Title:

Algorithm for Modeling Agricultural Land Cover Classification and Land Surface Temperature

Authors:

Ricardo G. Villar and Jigg Pelayo

Abstract: The rampant and unintended spread of urban areas resulted to the increase artificial component in the land cover types of the countryside bringing forth urban heat island (UHI). This paved the way to wide range of negative influences on the human health and environment which commonly relates to air pollution, drought, higher energy demand, and water shortage. The land cover also plays a relevant role in the process of understanding the interaction between ground surfaces with the local temperature. At the moment, depiction of the land surface temperature (LST) at city/municipality scale particularly in certain areas of Misamis Oriental, Philippines is inadequate as support to efficient mitigations and adaptations of the surface urban heat island (SUHI). Thus, this study purposely attempts to provide application on the Landsat 8 satellite data and low density Light Detection and Ranging (LiDAR) products in mapping out quality semi-automated LST model and crop-level land cover classification in a local scale through theoretical and algorithm base approach utilizing the principle of data analysis subjected to object based model. The paper also aims to explore the relationship between the derived LST and land cover classification. The results of the presented model showed the ability of comprehensive data analysis, GIS functionalities and object based image analysis (OBIA) approach with the integration of machine learning intelligence on automating complex map production processes with considerable efficiency and high accuracy. The findings may potentially lead to expanded investigation of temporal dynamics of land surface UHI. It is worthwhile to note that the environmental significance of these interactions can provide microclimate perception, awareness and improved decision making for land use planning and characterization at local and neighborhood scale. As a result, it can aid in facilitating problem identification, support mitigations and adaptations more efficiently.

Short Papers
Paper Nr: 7
Title:

The Computational Research on the Ancient near East (CRANE) Project: An Archaeological Data Integration, Simulation and Data Mining

Authors:

Stephen Batiuk, Tim Harrison and Lynn Welton

Abstract: Archaeology has emerged as one of the most dynamic and innovative disciplines in the humanities and social sciences, employing a truly interdisciplinary, collaborative approach and a continually expanding array of analytical research tools. Computer aided analysis of archaeological data is remarkably challenging given the heterogeneous nature of the material. Archaeologists generally aim to discover patterns, spatial relationships and other associations between different traits of the archaeological record. However, given the idiosyncratic and highly personal nature in which archaeological data is collected and analyzed, identifying these patterns and relationships offers many challenges. The Computational Research on the Ancient Near East (CRANE) initiative seeks to build an international multidisciplinary research collaboration, comprised of archaeologists, computer scientists, and paleo-environmental specialists, with the capacity to leverage a burgeoning corpus of data from a number of archaeological sites and fundamentally transform our knowledge of the civilizations of the ancient Middle East. The CRANE initiative is developing a sustainable, scalable, user-driven vehicle for large-scale data management and cross-project data integration, to harness the full evidentiary range produced by this uniquely rich cultural legacy. At the same time we are developing tools for data mining techniques, and to analyze simulate ancient societies using agent-based models of behavior.

Paper Nr: 17
Title:

Hex-utils: A Tool Set Supporting HexASCII Hexagonal rasters

Authors:

Luís Moreira de Sousa and João Paulo Leitão

Abstract: The advantages of hexagonal meshes over squared grids in discretising spatial variables have been known for long. Notwithstanding, the raster data formats used in geo-spatial disciplines to this purpose are still today almost exclusively reliant on squared grids. The HexASCII file format is a core element in an attempt to introduce hexagonal rasters to mainstream GIS, defining a simple vehicle to store and share such data structures. This article describes the hex-utils tool-kit, an Application Programming Interface (API) and a set of command line tools enabling the use of HexASCII rasters. Basic operations are supported: creation of new hexagonal rasters from different inputs and transformation into file formats readable by desktop GIS programmes. The API sets a framework for the development of further functionality.

Paper Nr: 33
Title:

Model Validation of an Open-source Framework for Post-processing INS/GNSS Systems

Authors:

Rodrigo Gonzalez, Carlos A. Catania and Paolo Dabove

Abstract: The development of new approaches in the GIS research community may require the use of a computational tool to post-process GNSS and inertial sensors data in order to get more accurate position, velocity, and orientation angles (attitude) information. An open-source framework for simulating integrated navigation systems (INS/GNSS) called NaveGo has been developed using MATLAB/GNU Octave and is freely available on-line. Although preliminary tests have shown that NaveGo appears to work properly, a deep examination must be carried out to confirm that this framework is an adequate tool for post-processing INS/GNSS information. The main goal of this work is to produce a validation methodology to show that NaveGo mathematical model works within its specifications. Firstly, static measurements from inertial sensors are processed and analysed by NaveGo applying the Allan variance for profiling typical errors. Some details of Allan variance procedure are exhibited. Then, performances of NaveGo and Inertial Explorer, a closed-source commercial package software for INS/GNSS integration, are compared for a real-world trajectory. It is statistically concluded that NaveGo presents close accuracy to Inertial Explorer for attitude and position. Consequently, it is demonstrated that NaveGo is an useful INS/GNSS post-processing framework that can be used in GIS applications.

Paper Nr: 35
Title:

Quantity Distribution Search using Sparse Representation Generated with Kernel-based Regression

Authors:

Akinori Asahara and Hideki Hayashi

Abstract: The number of records representing a quantity distribution (e.g. temperature and rainfall) requires an extreme amount of overhead to manage the data. We propose a method using a subset of records against the problem. The proposed method involves an approximation derived with kernel ridge regression in advance to determine the minimal dataset to be input into database systems. As an advantage of the proposed method, processes to reconstruct the original dataset can be completely implemented with Structured Query Language, which is used for relational database systems. Thus users can analyze easily the quantity distribution. From the results of experiments using digitized elevation map data, we confirmed that the proposed method can reduce the number of data to less than 1/10 of the original number if the acceptable error was set to 125 m.

Paper Nr: 39
Title:

Hydro Energy Resource Assessment in La Union, Region I, Philippines using Soil and Water Assessment Tool (SWAT)

Authors:

Jholeeh Charls Madalipay and Rodel Utrera

Abstract: Hydropower is the most important and widely-used renewable energy source. Hydro resource in the Philippines are abundant, it has been proven to be a viable source for clean energy for rural electrification and a source of mechanical energy to remote Philippine barangays. The study was aimed to use remote sensing data and technologies to assess the hydro-energy resource potential of the La Union river basins using Soil and Water Assessment Tool. Moreover, the study aims to identify potential locations for the establishment of hydro-energy power plants, its intake bays, powerhouse, penstocks, power generation capacity and classification. The study used the Soil and Water Assessment Tool, an ArcMap extension (ArcSWAT) to delineate and simulated the river flow using the available land use, soil and weather data obtained from Philippine agencies and world database. After the extraction of the river basins and subbasins, the delineated rivers riv1.shp was used to clip the Tagged Image File Format (TIFF) file of the La Union river basin. Extracted TIFF files was used to generated potential heads using the Head Determination Algorithm which was programed to search for minimum head of 20 meters and maximum predefined penstock lengths of 100 meters, 500 meters and 1000 meters. Power calculation and classification of potential sites was processed in ArcGIS software. Results showed potential locations for the development of hydro-power facilities in the province of La Union. Potential power generation, capacity and classification was also identified per feature.

Paper Nr: 57
Title:

First Experiences with Google Earth Engine

Authors:

José A. Navarro

Abstract: This paper presents the first experiences of the author with GEE (Google Earth Engine). A C++ image processing algorithm, still under development, was migrated to this new environment using GEE’s web interface and the JavaScript language. The idea is to discover the problems that might arise when migrating to this environment as well as to assess the presumable performance boost that should be achieved. A reduced —more didactic— version of the aforementioned algorithm is presented in a step-by-step way along with a brief description of the advantages and drawbacks —from the authors standpoint— of GEE.

Paper Nr: 58
Title:

Polygon-based Technique for Image Fusion and Land Cover Monitoring; Case Study World Islands/UAE

Authors:

Rami Al-Ruzouq

Abstract: The vast increase in the volume of remotely sensed data has created the need for robust data processing techniques that can fuse data observed by different acquisition systems. Image registration is an essential process for data fusion and aligning images captured by different sensors under different geometric and radiometric properties where conjugate features in images can properly align with same object space. Accurate image registration of the collected multiple temporal images would guarantee full understanding of the phenomenon under consideration. To solve the registration problem, the paradigm consists of selecting the most proper primitives, a representative transformation function, appropriate similarity measure and matching scheme. In this study, polygon-based image registration segments have been used for co-registration as well as the main element for a reliable change detection procedure. Change detection has been implanted on Dubai World Islands /UAE from 2004 until 2016. The approach relies on pixel-pixel subtraction of edge the extracted polygons features. The study shows the various range of development for the world islands / Dubai that has been accrued during 12 years. Quantitative analysis based on growth areas and the Annual Urban Spatial Expansion Index shows that study area has been increased by 4 times during 12 years. Polygon features were successfully used for image registration and change detection.

Paper Nr: 62
Title:

Adaptive Bootstrapping for Crowdsourced Indoor Maps

Authors:

Georgios Pipelidis

Abstract: Indoor mapping is an important and necessary enabler for many applications. However, indoor places and their services are very diverse. Furthermore, many technical approaches for indoor mapping exist. While there is fruitful research on combining some of these techniques, we show the need for flexible, customized bootstrapping for indoor maps. This includes mapping techniques but also intermediate services which enable data collection for improving maps and offering enhanced services. We illustrate examples of customizations of the process in a visual way and argue that the bootstrapping process needs to be adapted to specific buildings and end-user needs. This process-based view to indoor mapping leads to several research questions regarding the composition and intermediate steps in such process.

Posters
Paper Nr: 28
Title:

Study of the Floodflow Dynamics in the Pantanal of Cáceres/MT

Authors:

Edinéia Aparecida dos Santos Galvanin, Carla Bernadete Madureira Cruz and Raúl Sanchez Vicens

Abstract: The Brazilian Constitution lists some biomes and ecosystems considered as national patrimony, among which the Pantanal Matogrossense is inserted, legally establishing conditions that ensure the preservation of the environment, including the use of its natural resources (Article 225, § 4). In this context, the research proposes to analyze the dynamics of the floodflow in the Pantanal of Cáceres/MT and aims to contribute a methodology to obtain results that can support the planning, management, and monitoring of natural resources, as well as providing important information for agriculture, geology, hydrology, and ecological models. In this research, images from the MODIS sensor from the year 2015, with a resolution of 250 m, were used for the application of the methodology. The software ArcGis and Matlab were used for the image processing. The normalized difference water index obtained through 500 m resolution MODIS images was used as a priori analysis of the regions with water and without water, after a threshold was defined for all of the images and the processing was done to obtain the matrix with days with water and without water in the studied area. The results obtained provide a classification for the floodflow, the quality parameters derived using study area show that the proposed method performed better with classes < 30 (96%) and 180 - 270 (90%) of 4% and 10% of false positives, respectively.

Paper Nr: 40
Title:

Solar Resource Assessment of Batac City, Ilocos Norte, Philippines using Airborne Lidar and Topography-based Solar Model - As Part of the Renewable Energy Resource Assessment of Phil-Lidar 2 Program

Authors:

Richard Dean Yadao, Jholeeh Charls Madalipay and Nathaniel Alibuyog

Abstract: In this study, topography-based solar radiation model r.sun was used to estimate the monthly average daily clear sky Global Horizontal Irradiance (GHI) over Batac City, Ilocos Norte. High-resolution lidar data was used to derive the Digital Surface Model (DSM), slope and aspect rasters, and horizon raster maps taking the topographic shading into account. Linke Turbidity factor for each month were downloaded from the web to consider the atmospheric absorption of solar radiation. The generated monthly clear sky GHI rasters from r.sun were compared to the 2015 solar radiation data collected by the Mariano Marcos State University (MMSU) Agromet Station located near the Crop Research Laboratory, MMSU Batac. Statistical tests revealed that the measured values from the ground can be accurately estimated by the r.sun model with 95.34% proportion of variability. Land cover of the city was also extracted using Support Vector Machine (SVM) to get the building footprints and other open areas for the assessment of potential sites. The twelve GHI rasters were then clipped using the building footprints and bare earth areas from the extracted land cover.

Area 2 - Remote Sensing

Full Papers
Paper Nr: 27
Title:

Geographical Information System Applications for Pipeline Right of Way Aerial Surveillance

Authors:

Sergiy Sadovnychiy, Edgar A. Canul and Juan M. Lopez

Abstract: This article deals with a Geographical Information System (GIS) module which complements a video-infrared integrated application system for pipeline leakage detection inspection. This system is based on the theory that under pressure, leakage can occur and part of the product goes from liquid to gas state. In the leaking vicinity (over the land surface or in the waters) the temperature will change allowing appreciate a thermal difference that can be registered by the video-infrared equipment resulting in thermal contrast over the land, so that the infrared (IR) equipment can be used successfully for detecting and determining pollution due to petroleum. Similar arguments follow for the gas case. The system is designed to receive data from various electronic devices which operate in different frequency ranges. Data validation must be carried with suitable formulas to get the best final yield. Three types of information sensors form the major part of equipment: an infrared camera, a video camera and global positional system (GPS). Equipment, software and some inspection results using this system are presented. Tests show that the flight conditions (120-140 km/h, altitude of 400-500 m) are suitable for inspection services.

Paper Nr: 37
Title:

Sentinel-1 for Urban Areas - Comparison between Automatically Derived Settlement Layers from Sentinel-1 Data and Copernicus High Resolution Information Layers

Authors:

Arthur Lehner

Abstract: This work deals with the development of automatically derived settlement layers from Sentinel-1 data. The produced layers allow differentiation between built-up and non-built-up area. The results are visually compared with a standardized product of the Copernicus earth observation program, the Copernicus High Resolution Layer Imperviousness Degree. For evaluation of the accuracy, the European Settlement Map 2016 was chosen as a reference data set. In this study the ISODATA unsupervised classification algorithm is used for generating two layers that allow differentiation between built-up and non-built up area. The results reveal the suitability of Sentinel-1 data for urban areas mapping. The quality of the produced settlement layers are comparable to standardized products that are based on data from optical sensors e.g. Copernicus High Resolution Layer Imperviousness Degree or European Settlement Map 2016 respectively.

Paper Nr: 48
Title:

Urban Indicator for Database Updating - A Decision Tool to Help Stakeholders and Map Producers

Authors:

Bénédicte Navaro

Abstract: The issue of regular spatial databases updating is partly solved by the abundance of satellite images. It is, though, time consuming, requires qualified human resources, high financial costs and requests efficiency (Bernard, 2007). This article presents a semi-automatic tool for urban detection, to guide the stakeholders and the producers throughout the updating process. The industrial context of the study implies a fast, instantaneous applicative workflow, operational on various landscapes with different sensors; it is thus based on existing algorithms and software resources. The process is generic and adaptable, with a phase of uncorrelation, chaining a Minimum Noise Fraction transformation with a textural analysis, a learning phase, processed from an existing database, and an automatic modelling of the detected objects. The quantification of the results shows the successful recreation of the existing database (90% of its surface) with a 7% rate of potential big omissions. A specific highlight is made on the detection of disappeared buildings, corresponding to 17.5% of the potential important omissions. This process has run in “real” updating operations, on 1.5 and 6 meters resolution Spot6 images, a 15 meters Landsat-8 image and a 1.5 meters resolution Pleiades image. A quantification of its results is also proposed in this study.

Posters
Paper Nr: 59
Title:

A Case Study of Urban Extraction of Two Developing Municipalites of Northern Mindanao from Landsat8: An Approach Comparing Extracted Urban Features from Panchromatic Band against LiDAR Derived Classification

Authors:

Ricardo Villar

Abstract: The availability of some remotely sense data boosted mapping and managing earth resources. One of the most common and freely available satellite image data for remote sensing is Landsat 8 OLI/TIRS. Feature extraction using moderate resolution satellite data such as Landsat 8 data is still a challenging task due to its heterogeneity in nature and spectral resemblance with other land cover types. One of most interesting feature being classified in field of remote sensing is the rapid urbanization in developing countries. In order to assess the spatial and temporal nature of urbanization and land-cover change occurring across urban landscapes, city planners, decision-makers and researchers requires accurate up to date information. For this reason conventional approach of classification was being proposed in extracting urban feature by threshold parameterization using panchromatic band of Landsat 8. The extracted feature of built-up areas using the proposed method was assessed using the completeness and correctness method. The result showed a 77.34 % completeness and 45.5% correctness. The overall accuracy of extracted building features garnered 60.45% base on 50 sampled region of interest which is compared with extracted built-up using LiDAR as reference data. Due to this reason, the methodology proposed in this study is only effectively applicable in an image where there is less bare soil features present and urban element is distinctive against other land-cover feature.

Paper Nr: 66
Title:

Multi Sensor Satellite-based Change Detection Analysis

Authors:

Wasim Pervez, Shoab Ahmad Khan and Ejaz Hussain

Abstract: Change detection remains a challenging problem. Pre-classification and post classification techniques are used in change detection. Change detection techniques using pre-classification provide information only about changes i.e. change/no change but is unable to provide information about type of that change. It is easily applicable for change detection analysis of images with same number of spectral bands. Post classification change detection techniques provide information not only about changes but also about type of that change. Post classification change detection technique has advantages over other techniques in conditions where the change is limited due to small rate of change and where equal samples are used for classifications. This paper evaluated support vector machine (SVM) classification on Landsat-8 Operational Land Imager (OLI), Advanced Land Imager (ALI) and Hyperion data and post classification change detection analysis of SVM classified data from ALI to OLI data and from Hyperion to OLI data of the study area. The change detection results of SVM classified maps from ALI to OLI and from Hyperion to OLI showed considerable reduction in dam water mapping over time series. The results confirmed that OLI technology is appropriate for change detection analysis of the study area.

Area 3 - Modeling, Representation and Visualization

Full Papers
Paper Nr: 42
Title:

Multi-labelled Image Segmentation in Irregular, Weighted Networks: A Spatial Autocorrelation Approach

Authors:

Raphaël Ceré and François Bavaud

Abstract: Image segmentation and spatial clustering both face the same primary problem, namely to gather together spatial entities which are both spatially close and similar regarding their features. The parallelism is particularly obvious in the case of irregular, weighted networks, where methods borrowed from spatial analysis and general data analysis (soft K-means) may serve at segmenting images, as illustrated on four examples. Our approach considers soft memberships (fuzzy clustering) and attempts to minimize a free energy functional made of three ingredients : a within-cluster features dispersion (hard K-means), a network partitioning objective (such as the Ncut or the modularity) and a regularizing entropic term, enabling an iterative computation of the locally optimal soft clusters. In particular, the second functional enjoys many possible formulations, arguably helpful in unifying various conceptualizations of space through the probabilistic selection of pairs of neighbours, as well as their relation to spatial autocorrelation (Moran's I).

Paper Nr: 73
Title:

Morphotectonic Analysis between Crete and Kasos

Authors:

D. Lampridou, P. Nomikou, M. Alexandri, D. Papanikolaou, C. Hübscher and T. Ioannou

Abstract: The morphotectonic structure of the offshore area lying between Crete and Kasos is studied on the basis of new detailed bathymetric data. The resulting bathymetric map is presented. Qualitative analysis of morphological slope values, as well as the analysis of the watershed at the eastern part of Crete, confirms that the current seabed topographic relief reflects intense tectonic activity. The high morphological slope values indicate well-defined morphotectonic features, which mainly trend SW-NE and, secondarily, SSW-NNE. The main large-scale tectonic structures trend SW-NE correspond to the marginal faults that bound the Crete-Kasos basin. The overall basin geometry is an elongated rectangular which is divided into seven sub-basins, and the deepest one (2800m) is located at the eastern part of the area. Moreover, the complex regime of the seafloor includes submarine canyons, landslides and a well-defined slump with vertical displacement more than 400m.

Short Papers
Paper Nr: 55
Title:

Extending Land Administration Domain Models with a Goal Perspective

Authors:

Christophe Ponsard and Mounir Touzani

Abstract: Land administration covers many complex processes for managing rights over land, estimating value, gathering revenues and regulating land use. Its organisation typically relies on land registration and cadastre. Over the years, elaborated domain models have emerged and have been standardised. While those models address many dimensions of this domain, they fail to capture the rationale behind the design of the model or leave it quite implicit. In this paper, we propose to augment such domain models with a goal dimension in order to provide better guidance in the design of new systems and better understanding of existing systems, especially in the perspective of driving the wide variety of E.U. systems to evolve towards more interoperability. Our work relies on the KAOS goal-oriented framework for system design and highlights the use of sound structuring and reasoning techniques.

Paper Nr: 60
Title:

Modeling Standards and File Formats for Indoor Mapping

Authors:

Jorge Chen and Keith C. Clarke

Abstract: Indoor maps provide abstractions of the physical spaces where we spend most of our lives. General purpose indoor maps have historically taken the form of two-dimensional floor plans, commonly found in public venues such as shopping malls and cruise ships. Until recently, innovation and development of indoor maps have remained confined to urban planning and the building industry. Recent interest in indoor mapping for other applications has extended indoor mapping to 3D and to other domains, with a growing emphasis on commerce and general wayfinding. This paper reviews prevailing modeling standards and file formats relevant to the modeling and visualization of indoor spaces with the goal of assisting researchers and developers with finding appropriate formats for indoor modeling and visualization.

Posters
Paper Nr: 61
Title:

Development of Mapping Design for Agricultural Features Extracted from LiDAR Datasets

Authors:

Nerissa B. Gatdula, Mylene V. Jerez, Therese Anne M. Rollan, Ronalyn P. Jose and Coleen Dorothy U. Caranza

Abstract: Methods for agricultural feature extraction were developed to produce detailed (crop-level) agricultural land use/land cover (LULC) maps from high resolution LiDAR datasets. As of February 2017, available LiDAR data in the Philippines covers 125,200.00 sq.km. or 42.43% of the land area of the Philippines. As part of product generation, definition of mapping design was considered. This includes algorithm for post-classification, development of geodatabase schema, and map layouts. Output maps in custom and 1:10,000 scale JPEG maps, shapefiles and KMZ files are distributed to local government units, national government agencies and other stakeholders for use in planning and other applications. Definition of LULC classes and types is in accordance with the standard codes of Bureau of Soils and Water Management while 1:10,000 is based on National Mapping and Resource Information Authority map indexes. Initial classified maps are maintained in high resolution layers. Detailed objects are refined by determining the Minimum Mapping Unit (MMU). The use of mapping design has standardized the output agricultural resource maps of implementing universities involved in the Phil-LiDAR 2 Program. Models and automated workflows were developed to improve the implementation of the map design.

Paper Nr: 69
Title:

Application of SensorML in the Description of the Prototype Air Monitoring Network

Authors:

Mariusz Rogulski and Bogdan Dziadak

Abstract: The aim of this publication is to present the use of OGC standards – SensorML and Observations & Measurements – to describe the sensor network and measurement process in the prototype of air quality monitoring network launched in Nowy Sacz in Poland. Standards are used to create structures of relational databases to achieve interoperability through data collection in an orderly manner in the field of environmental data and in the description of monitoring process. This is important especially when the system consists of a number of low-cost measuring devices, that are designed to complement existing measurement network.

Area 4 - Knowledge Extraction and Management

Full Papers
Paper Nr: 52
Title:

Taming the Evolution of Big Data and its Technologies in BigGIS - A Conceptual Architectural Framework for Spatio-Temporal Analytics at Scale

Authors:

Patrick Wiener

Abstract: In the era of spatio-temporal big data, geographic information systems have to deal with a myriad of big data induced challenges such as scalability, flexibility or fault-tolerance. Furthermore, the rapid evolution of the underlying, occasionally competing big data ecosystems inevitably needs to be taken into account from the early system design phase. In order to generate valuable knowledge from spatio-temporal big data, a holistic approach manifested in an appropriate architectural design is necessary, which is a non-trivial task with regards to the tremendous design space. Therefore, we present the conceptual architectural framework of BigGIS, a predictive and prescriptive spatio-temporal analytics platform, that integrates big data analytics, semantic web technologies and visual analytics methodologies in our continuous refinement model.

Paper Nr: 71
Title:

Forecasting Asthma Hospital Admissions from Remotely Sensed Environmental Data

Authors:

Rute Almeida, Ana Cláudia Teodoro, Hernâni Gonçalves, Alberto Freitas and Ana Sa-Sousa

Abstract: Asthma has a major social impact and is prone to exacerbations. It is known that environmental factors, such as meteorological conditions and air pollutants, have a role over their occurrence. In a previous work, positive associations were found between hospital admissions due to asthma exacerbation at highly urbanized regions of Portugal and higher atmospheric NO2 levels, lower vegetation density and higher air temperatures, estimated using remote sensing. In this study we propose the use of georeferenced environmental factors to forecast the risk of hospital admissions due to asthma exacerbation. We applied linear discriminant analysis using monthly averages based in 2003–2007 environmental data to forecast positive monthly admission rates in municipalities of Lisboa district (Portugal) during 2008. Space-time estimates of nitrogen dioxide (NO2), vegetation density from MODIS Normalized Difference Vegetation Index (NDV I) and near-surface air temperature (Ta) were considered as independent variables. We identified over 65% of the combinations months/municipalities having hospital admissions in the testing set, with less than 10% of false positives. These results confirm that NO2, NDV I and Ta levels obtained from remotely sensed data can be used to predict hospital admissions due to asthma exacerbation, and may be helpful if applied in warning systems for patients in the future.

Short Papers
Paper Nr: 47
Title:

GIS-based Evacuation Routing using Capacity Aware Shortest Path Evacuation Routing Algorithm and Analytic Hierarchy Process for Flood Prone Communities

Authors:

Cinmayii Manliguez, Zarah Jean Diche and Maria Jezebel Jimenez

Abstract: Evacuation routing is one of the fundamental instruments for flood risk mitigation. In this study, features extracted from LiDAR data are used to create dynamic network composed of buildings and roads. Flood prone areas identified through flood models from Phil-Lidar 1 Project are considered by Capacity Aware Shortest Path Evacuation Routing algorithm to determine optimal routes. Road capacity and location of building features were also considered. Uncertainties among possible paths taken are evaluated through Decision Theory. Specific DT technique implemented to generate alternative routes for the possibility of detours is the Analytic Hierarchy Process. This study can help city governance in terms of planning and disaster risk reduction management.

Posters
Paper Nr: 10
Title:

Global-Detector - GIS- and Knowledge-based Tool for a Global Detection of the Potential for Production, Supply and Demand

Authors:

Wil Hennen

Abstract: Wageningen Economic Research has developed Global-Detector, a knowledge-based Geographic Information System that aims to detect the worldwide potential for production, demand and market strategies. At any spot in the world Global-Detector can show the values from a large amount of indicators, such as climate, infrastructure, and land characteristics. A large set of indicators is readily available for use without any GIS-processing, and the model builder together with the expert can instantly start building the knowledge base for the concerning research aim. Knowledge from experts is applied to combine relevant indicators to create new indicators. The concept of Global-Detector and 10 applications developed by this tool are described. As a generic tool with increased flexibility, Global-Detector has many application possibilities in a wide variety of fields.

Paper Nr: 14
Title:

GIS Open Source Application as a Support to a Hospital Morbidity Database - Hospital GIS

Authors:

Lia Duarte

Abstract: Geographical Information Systems (GIS) capabilities are increasing in health area. GIS have been used to investigate global health studies due to the huge capabilities to manipulation, storage, management, analysis, modelling and mapping of geographical data. A simple and intuitive graphic interface to represent spatially an administrative database information would be a great usefulness to the health community. In this work, an open source application was developed in Python language under a GIS open source software (QGIS). The application, incorporated in GIS software, is composed by two tabs: Symbology and Mapping. In order to test the developed application, a zone from Porto Metropolitan Area and a database with administrative data, hospital morbidity database, was considered. This data was previously added to PostGIS (an open source database) and automatically connected to the application. The difficulty of health professionals in the creation of multiple visualizations of tabular data defined by rigorous position, and the maps creation to later analysis and printing, can be overcome with this application. The large amount of data requires the connection to a free database in GIS environment enhancing the practical applicability, rapid, safe and efficient data representation.

Paper Nr: 38
Title:

Development of Hydrologic Dataset from Lidar Surveys for Watersheds in Ilocos Norte

Authors:

Christine Bumanglag and Nathaniel Alibuyog

Abstract: Ilocos Norte is one of the provinces in the Philippines which depends mainly on surface water for domestic, agricultural, and industrial water use especially for communities in mountainous areas. However, reliable information is critically lacking nowadays and inventories has been outdated throughout the province. Therefore, there is a need for alternative technologies to detailed hydrologic mapping. With the aim of developing a detailed and comprehensive hydrologic maps using Light Detection and Ranging (LIDAR) data, supplemented with other remotely-sensed imageries and ancillary information from LGUs and NGAs, the effectivity of implemented processing workflows was evaluated for 7 river basins in Ilocos Norte. Extraction of streams, wetlands and irrigation network in Cabungaan, Gabo, Cabayoagan, Natbaon, Pasuquin, NA-Pasuquin and San Mateo River Basins were done and their extents were determined. The effectivity of workflows in extracting features was evaluated using confusion matrix and reveals 98.13% accuracy. The versatility of the implemented workflows was demonstrated by its ability to be applied in other areas of the Philippines.

Area 5 - Domain Applications

Full Papers
Paper Nr: 41
Title:

Solid Waste Collection Routing Optimization using Hybridized Modified Discrete Firefly Algorithm and Simulated Annealing - A Case Study in Davao City, Philippines

Authors:

Cinmayii Manliguez and Princess Cuabo

Abstract: Modified Discrete Firefly - Simulated Annealing (MDF-SA) Algorithm was used to solve travelling salesman problem (TSP) using the tanh function for discretization. MDF-SA was tested on four (4) data instances from TSPLIB and the Davao City solid waste collection routing system. The objective of this study is to evaluate and compare MDF-SA with MDFA in terms of running time and solution quality. The data set selected from the TSPLIB are ST70, PR152, GR431, and TS225. The Davao City solid waste collection routing system is used in the hopes of finding a better solution from the current. Results show that MDF-SA and MDFA perform almost equally well on the data sets PR152 and GR43. MDFA performs better on using the TS225 data set, but MDF-SA performs much better on ST70. In general, the hybrid algorithm has produced better route system quality of the Davao City solid waste collection than the MDFA.

Paper Nr: 43
Title:

Modelling Urban Thermal Comfort: Evaluating the Impact of the Urban Requalification Project of Praça Duque De Saldanha and Avenida Da República in Lisbon

Authors:

Teresa Santos

Abstract: In dense urban areas, reducing traffic and increasing green areas is foreseen as a way of promoting urban comfort. Using the urban requalification project for Lisbon’s Avenidas Novas neighbourhood as a case study, the effects of vegetation on microclimate and urban comfort are evaluated. In this context, the ENVI-met software is used to model the present and the future urban scenario. The simulation results indicate: i) increased urban comfort in the morning and in the afternoon resulting from the decrease in temperature due to the presence of new green areas foreseen by the urban project; ii) a reduction of up to 3 degrees in the morning (9h) and up to 3 degrees in the afternoon (15h); iii) the model implemented in ENVI-met suits the urban and environmental characteristics of Lisbon and it is, therefore, desirable that future urban rehabilitation projects should consider ex ante simulation of this type.

Paper Nr: 53
Title:

A Web Platform for the Systematic Monitoring of Coastal Structures

Authors:

Alexandre Maia, Armanda Rodrigues and Rute Lemos

Abstract: Due to both its geographic location and maritime importance, Portugal is equipped with a large number of port infrastructures, the majority of which built for goals such as to guarantee the tranquility of the sheltered areas of the harbour basins, to help controlling sedimentation by guiding the currents, to protect water taken from thermoelectric plants, amongst others. In Portugal, the most common of these structures is the rubble-mound breakwater. Due to its characteristics, maintenance or repair works are common throughout its lifetime. However, the need for these repair works should be evaluated in advance, in order to avoid significant costs associated to those works or, even worse, the collapse of the structure. It is therefore quite important to evaluate the Present Condition of the structure, as well its Evolution and Risk Conditions. The Present Condition is periodically checked on-site and all relevant data gathered is recorded, by filling in inspection forms, in order to perform further comparisons and analyses with previous inspections of the structure, as to eventually characterize Evolution and Risk conditions. To expedite all this process and prevent likely occurrence of errors in data collection, a monitoring tool, supported through a map-based online geographic information system (WebGIS) was developed, enabling the georeferencing of the structures concerned. This system adapts to the location of the user’s device and to the capacities of the device itself. Media data, such as photos and videos can be associated to the structural data collected. The resulting platform was successfully evaluated by the involved researchers from Portuguese National Laboratory for Civil Engineering (which are the end users of the system), and by non-expert users.

Paper Nr: 72
Title:

Landslide Risk Assessment of the Santorini Volcanic Group

Authors:

V. Antoniou and S. Lappas

Abstract: The aim of this work is the assessment of landslide risk of the Volcanic Group of Santorini (Greece). The methodology followed was based on the application of multi-criteria analysis (Multicriteria Decision Analysis - MCDA) in a Geographical Information System (GIS) environment (ArcGIS 10.5). The original data was converted to digital form, georeferenced in the national coordinate system GGRS’87, and individual layers were processed through digitization. Furthermore, a geodatabase was created in order to enrich the spatial information with the requisite descriptive information. The above was necessary for further processing and analysis, which include the classification of factor’s data, according to the specific requirements of the region. Model Builder, an ArcGIS tool, was used to produce a Model which resulted in individual maps for each thematic layer, in addition to providing local authorities with an easy-to-use adaptable tool for landslide susceptibility mapping. Finally, a ranking method was used to generate criterion values for every factor. Then, each factor was weighted according to the estimated significance for causing landslides and the final susceptibility map was produced, depicting vulnerable areas.

Short Papers
Paper Nr: 25
Title:

Assessing the Vulnerability of Agricultural Crops to Riverine Floods in Kalibo, Philippines using Composite Index Method

Authors:

Ronalyn Jose, Ransie Joy Apura, Daniel Marc dela Torre, Ariel Blanco, Patricia Kristen Dela Cruz, Therese Anne Rollan, Eric Luis Tañada and Joyce Anne Laurete

Abstract: Evaluating the vulnerability of a system can serve as an effective planning tool in increasing resilience to a certain hazard. In this study, a vulnerability assessment of agricultural crops to river flooding in Kalibo, a municipality in Aklan, Philippines, was performed. The analysis included physical, agro-ecological, and socio-economic indicators clustered under the components of exposure, sensitivity, and adaptive capacity. Indicators relevant for a composite index measuring degree of vulnerability to flooding were identified and corresponding weights were determined using Analytic Hierarchy Process (AHP). Various datasets were acquired using Light Detection and Ranging (LiDAR) remote sensing and participatory methods such as focus group discussions (FGDs) and key informant interviews (KIIs). The barangay-level (village-level) and gridded (500m x 500m) vulnerability maps produced using Index Method and GIS were validated through field surveys and by comparison with historical accounts of disasters and their corresponding impacts on agricultural productivity. It was concluded that the most exposed barangays were those near bodies of water and having vast agricultural land cover. Though the physical and environmental attributes of an area are substantial in determining risk, the vulnerability of the subject area was shown to be influenced by its internal (exposure) and external (sensitivity and adaptive capacity) factors. Thus, knowing and acting on indicators that are within human influence is essential in minimizing the effects of inevitable and uncontrollable phenomena.

Paper Nr: 68
Title:

Flood Modeling using Gis and LiDAR of Padada River in Southeastern Philippines

Authors:

Joseph E. Acosta, Ryan Keath L. De Leon and Judy Rose D. Hollite

Abstract: Located along the typhoon belt in the Pacific, Philippines is visited annually by an average of 20 typhoons. This brought frequent flooding to communities and caused damage to flood prone residents. This study is aimed to generate GIS flood model to simulate flood inundation using Synthetic Aperture Radar (SAR) data and Digital Terrain Model (DTM) derived from Light Detection and Ranging (LiDAR) datasets. Open-sourced HEC-HMS and HEC-RAS Models were used. HEC-GeoRAS in ArcMap was used to preprocess geospatial data of Padada River basin in the Southern Philippines. The result of the study has identified inundated areas and communities for a 24-hour 5, 25, and 100- year return periods as well as flooded critical facilities in the flood plains. The output of this study can be used in planning and predicting flood risks for mitigation.

Posters
Paper Nr: 64
Title:

Land Use Planning for Sustainable Development of Coastal Regions

Authors:

Areti Kotsoni

Abstract: The current paper will focus on the coastal zone of Georgioupoli and its vulnerability as a result of the lack of spatial planning. The case study is selected because it concentrates the characteristics of a typical coastal touristic zone, which faces rapid intense unplanned touristic expansion. The examined zone has been diachronically influenced by the liberalization of construction regulations, an unqualified private sector emerged, hastily developing construction mostly without government oversight and without building permits. We present a concept for planning sustainable development in coastal regions.

Workshop

GAMOLCS 2017

Short Papers
Paper Nr: 1
Title:

Improving SLEUTH Calibration with a Genetic Algorithm

Authors:

Keith C. Clarke

Abstract: A review of calibration methods used for cellular automaton models of land use and land cover change was performed. Calibration advances have been achieved through machine learning algorithms to either extract land change rules, or optimize model performance. Many models have now automated the calibration process, reducing the need for subjective choices. Here, the brute force calibration procedure for the SLEUTH CA-based land use change model was replaced with a genetic algorithm (GA). The GA calibration process populates a “chromosome” with five parameter combinations (genes). These combinations are then used for model calibration runs, and the most successful selected for mutation, while the least successful are replaced with randomly selected values. Default values for the constants and rates of the genetic algorithm were selected from SLEUTH applications. Model calibrations were completed using both brute force calibration and the GA. The GA model performed as well as the brute force method, but used vastly less computation time with speed up of about 3 to 22. The optimal values for GA calibration are set as the defaults for SLEUTH-GA, a new version of the model. This paper is a contraction of Clarke (in press), which reports on the full set of results.

Paper Nr: 2
Title:

Cartographic Scale and Minimum Mapping Unit Influence on LULC Modelling

Authors:

David García Álvarez

Abstract: Two models at two different scales (1:25.000 and 1.100.000) were calibrated using two different Land Use and Land Cover maps at such cartographic scales (SIOSE and CORINE) and with a different Minimum Mapping Unit (0.2-0.5ha and 25ha). Differences between models were assessed through cross-tabulation analysis (quantity and allocation disagreement) and spatial metrics (pattern disagreement). The models results have been very different depending on the scale considered, although most of the disagreement comes from the contrasting input maps. In any case, the scale at which the models were calibrated have proved to influence the pattern modelled and the quantity and allocation of changes.

Paper Nr: 3
Title:

Mapping Socio-biodiversity: Do Old Modelling Tools Suit New Challenges?

Authors:

Sónia Carvalho Ribeiro, William Leles da Costa, Amanda Ribeiro de Oliveira, Danilo da Silveira Figueira, Isabella Lorenzini da Silva Teixeira and Lilian Aline Machado

Abstract: This work shows an original use of classical methods in land change modelling. The aim of this study is to model yields (productivity) and economic importance (annual rents) of rubber and Brazil nut in the Brazilian Amazon. Biophysical variables related to rubber and Brazil nut yields as well as market access (commercialization) were used to model favorability of productivity using Weights of Evidence (WofE) method. To favorability of productivity were assigned yields base on case study data. The economic model then combines the map of yields with output prices and costs of collection, processing, and transport to estimate annual rents per hectare for a specific forest plot. For estimating transport costs we used cost friction surface modelling tools. Our results show that yields for Brazil nut averages 8.19±7.41 kg ha-1year-1 and rent averages US$ 5.05±7.49 ha-1year-1. Rubber average yields is of 3.53 kg/ha/year and rubber rents average US$ 0.56±0.7ha-1year-1. Coupling biophysical and economic models allowed us to explore which environmental and governance improvements are needed to avoid deforestation and forest degradation in the Brazilian Amazon. Our results also show that despite some methodological issues and the recurrent call for “new” modelling approaches for addressing the complexity of socio ecological systems, “old” modelling tools such as Weight of Evidence and Cost Friction Surface, are still suited for addressing the challenge of mapping socio-biodiversity.

Paper Nr: 4
Title:

Modeling Land Change using One or Two Time Points based Calibration - A Comparison of Factors

Authors:

María Teresa Camacho Olmedo

Abstract: One of land change model parameters in calibration step relates to how changes over time and space are considered in the model. A land change model can be calibrated with the state at one time point or with the difference between two time points. The purpose is describing land use and cover (LUC) state patterns, i.e. one time point calibration, and LUC transition patterns, i.e. two time points. For a case study in Spain we obtained the collections of factors for two calibration periods at one time point (dates 2000 and 2006) and the collections of factors for two calibration periods between two time points (periods 1990-2000 and 2000-2006). Evidence likelihood is used to transform the explanatory variables into factors. The objective of this paper is to compare these four collections of factors to show how the choice of reference maps influences the factors and how these factors highlight the change patterns in two different calibration periods and in the calibration of two models. As a following step the detailed results for the different factors and LUC categories are analysed.

Paper Nr: 5
Title:

Land Change Modeling Handling with Various Training Dates

Authors:

Martin Paegelow

Abstract: Popular modeling tools for land change simulation, especially those using Markov chains, undertake model training based only on two land use / cover (LUC) maps. This paper analyses uncertainty and potential errors caused by taking into account only two former, model known, LUC maps. This is illustrated by a simple data set of six LUC maps allowing various Markovian transition matrices; a range even larger by considering different confidence levels. Results underline the randomness in choice of only two training dates. Authors propose alternative methods to Markov chains integrating all available LUC maps in order to simulate forecasting scenarios. To do so, they incorporate all possible LUCC (land use / cover change) budgets to perform simple arithmetic combinations between the six training dates. Comparing Markov chain transitions based on two training dates and alternatively performed change rates taking into account all training dates results to important differences. This study underlines the importance of the choice of training dates during model calibration for path-dependent simulations.

Paper Nr: 6
Title:

Modelling Transport-based Land-use Scenarios in Bogota

Authors:

Francisco Escobar and Daniel Paez

Abstract: Economic growth experienced in Colombia since 2001 has impacted on heavier traffic levels in the capital city of Bogota which in turn have worsened air pollution indicators and environmental public health conditions. Different political options competing at municipal elections have included their respective proposals for public transport in their programs. Impact expected from each of these scenarios makes it necessary to implement models allowing their assessment. Given this need, we present the Bogota Land Development Model (BoLD), a practical implementation of a Land-use Cover Change (LUCC) simulation based on two different public transport scenarios; a highway-based network and a suburban rail system. Transport scenarios are combined with options to expand the city into natural reserves. Customized geospatial analyses were developed for calculating accessibility distance decay factors based on overtime-spatial decay determination (OSDD) method. Results of the scenarios are presented both in maps and in “mobility circles”. Validation of the results suggests that OSDD and the mobility circles appear to contribute to better information to decision-making when evaluating urban scenarios driven by transport projects.

Paper Nr: 7
Title:

Using Constraint Cellular Automata to Simulate Urban Development in a Cross-border Area

Authors:

J.-P. Antoni and V. Judge

Abstract: Urban sprawl and space consumption have become key issues in sustainable territorial development. Traditional planning approaches are often insufficient to anticipate their complex spatial consequences, especially in cross-border areas. Such complexity requires the use of dynamic spatial simulations and the development of adapted tools like LucSim, a CA-based tool offering solutions for sharing spatial data and simulations among scientists, technicians and stakeholders. Methodologically, this tool allows us to simulate future land use change by first quantifying and then locating the changes. Quantification is based on Markov chains and location on transition rules. The proposed approach is implemented on the Strasbourg-Kehl cross-border area and calibrated with three contrasting prospective scenarios to try to predict cross-border territorial development.

Paper Nr: 8
Title:

Future Land Use Change Dynamics in Natural Protected Areas - Madrid Region Case Study

Authors:

Marta Gallardo and Javier Martinez-Vega

Abstract: Natural protected areas are declared to safeguard their environment, goods and services. However, sometimes they are affected by land use changes related to human activity, which affects their ecosystem functions and their sustainability. Problems such as fragmentation or low habitat connectivity are some of its consequences. Developing future land use scenarios is essential if a preventive approach to the management of protected areas is to be adopted. In this paper, three different land use change scenarios in natural protected areas in Madrid region are modelled: a “business as usual” scenario, an economic crisis scenario and a green scenario. All protected areas are studied, from National and Nature Parks to Special Areas of Conservation and Special Protection Areas; changes in a buffer area of 5 km around PAs are also studied. The CLUE model (based on logistic regression) is used. Biophysical, socio-economic and accessibility factors and incentives and restrictions are considered. In recent decades, the region of Madrid has experienced intense urban and infrastructure development (48,332 ha). Protected areas have been affected by this urbanization process (almost 5,000 ha) and its surroundings (30,000 ha). These findings should alert land use planners and the managers of protected areas to the potential threats.

Doctoral Consortium

DCGISTAM 2017

Full Papers
Paper Nr: 1
Title:

The Use of Geotechnologies to Analyze the Influence of the Road Infrastructure on the Landscape

Authors:

Aimara Reyes

Abstract: The projects devoted to the construction of transport infrastructure represent social and economic benefits that provide communication between different regions, which makes the transportation of people and goods easier while providing social and economic development at different local, regional and national scales and improving the quality of life of the inhabitants. Nevertheless, the construction and maintenance of roads have negative effects on the environment, especially at the landscape scale. The identification and evaluation of effects such as the landscape heterogeneity are important to design strategies oriented to mitigate and compensate such impacts. The growth of road infrastructure is becoming more and more important due to the environmental impacts produced at different territorial scales: urban, periurban, and rural. The knowledge of the landscape diversity and the understanding of the changing spatial and temporal patterns associated with roads are necessary, especially in areas with high spatial dynamic. For example, in urban and periurban areas, the urbanization processes will continue and the requirements of connection between urban centers will be greater, requiring a large number of roads and maintenance of the existing infrastructure. However, without efficient planning tools that protect the spatial dynamics of the ecosystems, a sustainable environment could not be available over time. One challenge is the use of different geotechniques and statistical methods, in addition to simulation models, to analyze and predict the effects of road infrastructure on the temporal and spatial changes of the landscape. Thus, the main objective of this PhD study is to achieve an adequate methodology through the use of existing models and techniques for the analysis of heterogeneous landscapes, and mainly the influence of the transport infrastructure on the fragmentation and diversity of natural ecosystems.

Paper Nr: 2
Title:

The Use of Airborne Laser Scanning Data to Study Birds Habitat Requirements

Authors:

Fogl Michal and Moudrý Vítězslav

Abstract: Vegetation structure is an important factor that influence species diversity and distribution. However, field measurement of vegetation structure is labour intensive and of limited spatial extents. Laser altimetry (LiDAR) is an active remote sensing technology that has enabled measurement of vegetation 3D structure over large areas. We will use airborne LiDAR acquired over Krkonose Mountains National Park, Czech Republic with average point density 6 p/m2 in combination with in situ measurements of forest composition and structure and bird data collected for Atlas of breeding bird distribution in the Krkonose to: (1) evaluate the accuracy of LiDAR derived forest stand characteristics with field measurements; (2) assess the utility of LiDAR derived variables to explain bird species richness and single species presence and (3) compare results of existing studies with our results to investigate whether the relationship between vegetation structure and particular bird species is consistent across species ranges.

Paper Nr: 3
Title:

The Quality of Spatial Data and Its Effect on Species Distribution Models

Authors:

Gábor Lukáš and Moudrý Vítězslav

Abstract: Biodiversity is declining throughout the world and its monitoring is an ongoing challenge of modern biogeography and macroecology. To deal with biodiversity crisis data from both remote sensing and in situ observations are often utilized. To successfully utilize these two complementary sources various modelling approaches has been adopted and plays an important role. The objective of the modelling is to relate in situ response variable (e.g. species distribution) and remotely sensed explanatory variables (e.g. derived from digital elevation models) to describe the relationship between these two or to predict unknown values of the biodiversity response variable. Species distribution models (SDMs) is the most popular example of such analysis and are widely used in biogeography, macroecology and nature conservation for both fundamental and applied research purposes. The quality of spatial data is currently one of the major limiting factors of the modelling, however, studying its influence with real species is difficult. Virtual species, on the other hand, allows to easily determine how for example different methods of data collection, its quality or used scale, affect models. The aim of this research is to address data quality in SDMs.

Paper Nr: 4
Title:

The Use of 3DGIS Models to Develop a New Model of Urban Management: The Fortaleza- Brasil Case Study

Authors:

Caroline Camara

Abstract: The uncontrolled urban growth occurred in several cities of Brazil, source of urban and environmental degradation was allowed by the local authority to give fast answers to individual requests related with the natural or built environment. The extensive territory of Fortaleza, the most densely populated capital of Brazil, among the 26 state capitals and 01 federal district, is marked by urban vocations and environmental peculiarities that influence the land use, growing without any integration between the environmental conditions and the urban design. To solve this lack of communication we intend to improve the current methodology for territorial management, using a 3DGIS approach.

Open Communications

OCGISTAM 2017

Short Papers
Paper Nr: 2
Title:

Mobile Tunnel Mapping in a GNSS - Denied Environment

Authors:

Michael A. Chapman and Qing-Quan Li

Abstract: The need for reliable systems for capturing precise detail in tunnels has increased as the number of tunnels (e.g., for cars and trucks, trains, subways, mining and other infrastructure) has increased and the age of these structures and, subsequent, deterioration has introduced structural degradations and eventual failures. Due to the hostile environments encountered in tunnels, mobile mapping systems are plagued with various problems such as loss of GNSS signals, drift of inertial measurements systems, low lighting conditions, dust and poor surface textures for feature identification and extraction. A tunnel mapping system using alternate sensors and algorithms that can deliver precise coordinates and feature attributes from surfaces along the entire tunnel path is presented. This system employs image bridging or visual odometry to estimate precise sensor positions and orientations. The fundamental concept is the use of image sequences to geometrically extend the control information in the absence of absolute positioning data sources. This is a non-trivial problem due to changes in scale, perceived resolution, image contrast and lack of salient features. The sensors employed include forward-looking high resolution digital frame cameras coupled with auxiliary light sources. In addition, a high frequency lidar system and a thermal imager are included to offer three dimensional point clouds of the tunnel walls along with thermal images for moisture detection. The mobile mapping system is equipped with an array of 16 cameras and light sources to capture the tunnel walls. Continuous images are produced using a semi-automated mosaicking process. Results of preliminary experimentation are presented to demonstrate the effectiveness of the system for the generation of seamless precise tunnel maps.