NON-PARAMETRIC STATISTICAL APPROACH TO CORRECT SATELLITE RAINFALL DATA IN NEAR-REAL-TIME FOR RAIN BASED FLOOD NOWCASTING

Floods resulting from intense rainfall are one of the most disastrous hazards in many regions of the world since they contribute greatly to personal injury and to property damage mainly as a result of their ability to strike with little warning. The possibility to give an alert about a flooding situation at least a few hours before helps greatly to reduce the damage. Therefore, scores of flood forecasting systems have been developed during the past few years mainly at country level and regional level. Flood forecasting systems based only on traditional methods such as return period of flooding situations or extreme rainfall events have failed on most occasions to forecast flooding situations accurately because of changes on territory in recent years by extensive infrastructure development, increased frequency of extreme rainfall events over recent decades, etc. Nowadays, flood nowcasting systems or early warning systems which run on real- time precipitation data are becoming more popular as they give reliable forecasts compared to traditional flood forecasting systems. However, these kinds of systems are often limited to developed countries as they need well distributed gauging station networks or sophisticated surface-based radar systems to collect real-time precipitation data. In most of the developing countries and in some developed countries also, precipitation data from available sparse gauging stations are inadequate for developing representative aerial samples needed by such systems. As satellites are able to provide a global coverage with a continuous temporal availability, currently the possibility of using satellite-based rainfall estimates in flood nowcasting systems is being highly investigated. To contribute to the world's requirement for flood early warning systems, ITHACA developed a global scale flood nowcasting system that runs on near-real-time satellite rainfall estimates. The system was developed in cooperation with United Nations World Food Programme (WFP), to support the preparedness phase of the WFP like humanitarian assistance agencies, mainly in less developed countries. The concept behind this early warning system is identifying critical rainfall events for each hydrological basin on the earth with past rainfall data and using them to identify floodable rainfall events with real time rainfall data. The individuation of critical rainfall events was done with a hydrological analysis using 3B42 rainfall data which is the most accurate product of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) dataset. These critical events have been stored in a database and when a rainfall event is found in real-time which is similar or exceeds the event in the database an alert is issued for the basin area. The most accurate product of TMPA (3B42) is derived by applying bias adjustments to real time rainfall estimates using rain gauge data, thus it is available for end-users 10-15 days after each calendar month. The real time product of TMPA (3B42RT) is released approximately 9 hours after real-time and lacks of such kind of bias adjustments using rain gauge data as rain gauge data are not available in real time. Therefore, to have reliable alerts it is very important to reduce the uncertainty of 3B42RT product before using it in the early warning system. For this purpose, a statistical approach was proposed to make near real- time bias adjustments for the near real time product of TMPA (3B42RT). In this approach the relationship between the bias adjusted rainfall data product (3B42) and the real-time rainfall data product (3B42RT) was analyzed on the basis of drainage basins for the period from January 2003 to December 2007, and correction factors were developed for each basin worldwide to perform near real-time bias adjusted product estimation from the real-time rainfall data product (3B42RT). The accuracy of the product was analyzed by comparing with gauge rainfall data from Bangladesh and it was found that the uncertainty of the product is less even than the most accurate product of TMPA dataset (3B42

Validation Protocol for Emergency Response Geo-information Products

Europe is making a significant effort to develop (geo)information services for crisis management as part of the Global Monitoring for Environment and Security GMES) programme. Recognising the importance of coordinated European response to crises and the potential contribution of GMES, the Commission launched a number of preparatory activities in coordination with relevant stakeholders for the establishment of an Emergency Response GMES Core Service (ERCS). GMES Emergency Response Services will rely on information provided by advanced technical and operational capabilities making full use of space earth observation and supporting their integration with other sources of data and information. Data and information generated by these services can be used to enhance emergency preparedness and early reaction to foreseeable or imminent crises and disasters. From a technical point of view, the use of geo-information for emergency response poses significant challenges for spatial data collection, data management, information extraction and communication. The need for an independent formal assessment of crisis products to provide operational services with homogeneous and reliable standards has recently become recognized as an integral component of service development. Validation is intended to help end-users decide how much to trust geo-information products (maps, spatial dataset). The focus, in this document, is on geo-information products, in particular those derived from Earth Observation data. Validation principles have been implemented into a protocol, as a tool to check whether the products meet standards and user needs. The validation principles, methods, rules and guidelines provided in this document aim to give a structure that guarantees an overall documented and continuous quality of ERCS products.JRC.DG.G.2-Global security and crisis managemen

Investigating the effectiveness of an efficient label placement method using eye movement data

This paper focuses on improving the efficiency and effectiveness of dynamic and interactive maps in relation to the user. A label placement method with an improved algorithmic efficiency is presented. Since this algorithm has an influence on the actual placement of the name labels on the map, it is tested if this efficient algorithms also creates more effective maps: how well is the information processed by the user. We tested 30 participants while they were working on a dynamic and interactive map display. Their task was to locate geographical names on each of the presented maps. Their eye movements were registered together with the time at which a given label was found. The gathered data reveal no difference in the user's response times, neither in the number and the duration of the fixations between both map designs. The results of this study show that the efficiency of label placement algorithms can be improved without disturbing the user's cognitive map. Consequently, we created a more efficient map without affecting its effectiveness towards the user

Possibilities of eye tracking and EEG integration for visual search on 2D maps

This on-going research paper explores (the possibilities to integrate eye tracking (ET) and electroencephalogram (EEG) for cartographic usability research. While ET, on one hand, provides observations and measurements related to gaze movements, EEG, on the other hand, helps to monitor and measure electrical activity occurring at different locations in the brain with a high temporal resolution. Therefore, combining ET and EEG introduces a holistic approach enabling to measure both overt and covert attention, and additionally, may reveal insights on individual’s different strategies of spatial cognition, if there is any. In this context, we introduce the experimental design settings for visual search task on simplified 2D static maps considering expert and novice participants, outlining methodological proposal and possible analyses. The paper mainly discusses the technical and theoretical issues of ET-EEG integration and mentions potential benefits of implementing EEG in cartographic usability research to indicate its value for future studies

Comparing Different Levels of Interactivity in the Visualization of Spatio-Temporal Data

The Internet and other advances in technology have dramatically affected cartography in recent decades and yet these new capabilities have not been adequately evaluated for effectiveness. Are dynamic maps more effective than traditional static paper maps in allowing users to visualize spatio-temporal patterns? How important is a higher level of interactivity in visualizing data? Which format is preferred? To examine these questions, human subject tests were conducted to evaluate different levels of interactivity as represented by 1) a static paper map series; 2) an animated map with \u27VCR\u27-type controls; and 3) a toggle map featuring an interactive temporal legend. Results indicate that while the level of interactivity did not affect accuracy of answers to questions regarding spatio-temporal patterns, the total amount of time in which these questions were answered lessened as the level of interactivity increased. Overall, test subjects were more enthusiastic towards the tools featuring greater interactivity

From the cartographic gaze to contestatory cartographies

Rene Descartes declared in the 16th Century that the world was now dominated by the visual, a notion that would be seen as defining the Enlightenment (Descartes, cited in Potts, 2015). As the increased dominance of seeing and the desire to visualise the world cohered with the production of increasingly accurate tools of measurement and the advent of the printing press, cartography emerged as a discipline, often used as tool of oppression and dominance. Cartographic visualizations, afforded the creator, and user, a Gods eye view of the world. Following others (See Casas-Cortés et. al., 2013; Koch, 1998), this chapter refers to this way of seeing the world from above as the Cartographic Gaze. First, the chapter briefly examines the historical emergence of the Cartographic Gaze before turning to a discussion about how the proliferation of geographic imaging technologies and digital tools simultaneously further embedded this gaze into mapping practice, while also diffusing such practices of mapping to broader populations. Discussing the rise of participatory mapping and counter mapping under the rubric of contestatory cartographies, the chapter presents some of the challenges that face those attempting to create alternative maps of their worlds, and the ways in which they become entrapped by the pervasiveness of the Cartographic Gaze. We use the term participatory mapping to refer to methodologies for map-making based around the participation of those who the map will represent. And we employ the term counter mapping to reference those mapping practices that explicitly seek to expose and challenge power relations. In specific, we look at how the colonizing origins of the Cartographic Gaze limit what it is possible to do with these alternative mapping practices

Evaluating the efficiency of typographic design : gender and expertise variation

Although the efficiency of label placement algorithms has been studied extensively, few studies considered the influence of the label designs on the efficiency of map readers. Labels are one of the most important elements on the map as they can provide more information than other symbols can. The design of the labels does have to stress the theme, shape and functionality of the associated objects, which results in a more efficient interpretation of the map content by the user. How the label designs can enhance the map readers' efficiency (and thus the quality of the maps themselves) is the main objective of this study. A user study was conducted in which the participants were asked to locate a target label on a map. Different label designs were implemented across the trials. The participants' reactions times were registered to measure their efficiency and statistically analysed using a one-way ANOVA. Two different users' characteristics were considered: gender and expertise. Related to the size, shape, orientation and texture of the labels, a number of significant differences (P<0.05) and trends were located. Differences in efficiency between males and females, on the one hand, and between novices and experts, on the other hand, were also described statistically. Consequently, recommendations can be formulated regarding the design of labels in order to obtain more efficient maps, keeping in mind the map users' characteristics

Methods to Improve and Evaluate Spatial Data Infrastructures

This thesis mainly focuses on methods for improving and evaluating Spatial Data Infrastructures (SDIs). The aim has been threefold: to develop a framework for the management and evaluation of an SDI, to improve the accessibility of spatial data in an SDI, and to improve the cartography in view services in an SDI. Spatial Data Infrastructure has been identified as an umbrella covering spatial data handling procedures. The long-term implementation of SDI increases the need for short/middle term feedbacks from different perspectives. Thus, a precise strategic plan and accurate objectives have to be defined for the implementation of an efficient environment for spatial data collection and exchange in a region. In this thesis, a comprehensive study was conducted to review the current methods in the business management literature to approach to an integrated framework for the implementation and evaluation of SDIs. In this context, four techniques were described and the usability of each technique in several aspects of SDI implementation was discussed. SDI evaluation has been considered as one of the main challenges in recent years. Lack of a general goal oriented framework to assess an SDI from different perspectives was one of the main concerns of this thesis. Among a number of the current methods in this research area, we focused on the Balanced Scorecard (BSC) as a general evaluation framework covering all perspectives in an SDI. The assessment study opened a window to a number of important issues that ranged from the technical to the cartographic aspects of spatial data exchange in an SDI. To access the required datasets in an SDI, clearinghouse networks have been developed as a gateway to the data repositories. However, traditional clearinghouse networks do not satisfy the end user requirements. By adding a number of functionalities, we proposed a methodology to increase the percentage of accessing required data. These methods were based on predefined rules and additional procedures within web processing services and service composition subjects to develop an expert system based clearinghouses. From the cartography viewpoint, current methods for spatial data presentation do not satisfy the user requirements in an SDI environment. The main presentation problem occurs when spatial data are integrated from different sources. For appropriate cartography, we propose a number of methods, such as the polygon overlay method, which is an icon placement approach, to emphasize the more important layers and the color saturation method to decrease the color saturation of the unimportant layers and emphasize the foreground layer according to the visual hierarchy concept. Another cartographic challenge is the geometrical and topological conflicts in data shown in view services. The geometrical inconsistency is due to the artificial discrepancy that occurs when displaying connected information from different sources, which is caused by inaccuracies and different levels of details in the datasets. The semantic conflict is related to the definition of the related features, i.e., to the information models of the datasets. To overcome these conflicts and to fix the topological and geometric conflicts we use a semantic based expert system by utilizing an automatic cartography core containing a semantic rule based component. We proposed a system architecture that has an OWL (Web Ontology Language) based expert system to improve the cartography by adjusting and resolving topological and geometrical conflicts in geoportals

Survey on geographic visual display techniques in epidemiology: Taxonomy and characterization

Many works have been done on the topic of Geographic Visual Display with different objectives and approaches. There are studies to compare the traditional cartography techniques (the traditional term of Geographic Visual Display (GVD) without Human-Computer Interaction (HCI)) to Modern GIS which are also known as Geo-visualization, some literature differentiates and highlight the commonalities of features and architectures of different Geographic Visual Display tools (from layers and clusters to dot and color and more). Furthermore, with the existence of more advanced tools which support data exploration, few tasks are done to evaluate how those tools are used to handle complex and multivariate spatial-temporal data. Several test on usability and interactivity of tools toward user's needs or preferences, some even develop frameworks that address user's concern in a wide array of tasks, and others prove how these tools are able to stimulate the visual thought process and help in decision making or event prediction amongst decision-makers. This paper surveyed and categorized these research articles into 2 categories: Traditional Cartography (TC) and Geo-visualization (G). This paper will classify each category by their techniques and tasks that contribute to the significance of data representation in Geographic Visual Display and develop perspectives of each area and evaluating trends of Geographic Visual Display Techniques. Suggestions and ideas on what mechanisms can be used to improve and diversify Geographic Visual Display Techniques are provided at the end of this survey