IMPREMENTATION OF VGI-BASED GEOPORTAL FOR EMPOWERING CITIZEN ’ S GEOSPATIAL OBSERVATORIES RELATED TO URBAN DISASTER MANAGEMENT

The volunteered geospatial information (VGI) will be efficient and cost-effective method for generating and sharing large disasterrelated geospatial data. The national mapping organizations have played the role of major geospatial collector have been moving toward the considering public participation data collecting method. Due to VGI can conduct to encourage public participation and empower citizens, mapping agency could make a partnership with members of the VGI community to help to provide well-structured geospatial data. In order to effectively be understood and sharing the public semantics, datasets and action model of the public participation GeoPortal, the implemented VGI-GeoPortal designated as the basis of ISO 19154, ISO 19101 and OGC Reference Model. The proof of concepts of VGI-GeoPortal has been implemented urban flooding use-case in Republic of Korea to collect from the public, and analyze disaster-related geospatial data including high-disaster potential information such as the location of poor drainage sewer, small signs of occurring landslide, flooding vulnerability of urban structure, and etc.


INTRODUCTION
Many studies have shown that analysis capabilities based on GIS technology has enhanced decision making.Geospatial technologies support decision making in all phases of the disaster management cycle (Warfield, 2012).At the same time, it has been gradually understood that up-to-date geospatial data for disaster management, especially data during the response phase, is quite important.Besides geospatial data describing the disaster, information gathered from the citizens and other organizations are also valuable for emergency management and decision making.The volunteered geospatial information (VGI) could be efficient and cost-effective method for generating and sharing large disaster-related geospatial data.When a disaster or emergency situation happens somewhere it includes the governmental and the public activities.The disaster preparedness and response phase of disaster management need GIS and GIS professionals to help decision makers identify vital reasons of the possible damage and assign response resource.Recently, the web, smart device and explosive spatially-related service-ubiquitous computing technologies -have ushered in a new era where the public are not only information consumers, but also act as producers of new, enriched information including disasterrelated geospatial data.The national mapping organisations (NMOs) that have played the role of major geospatial collector have been moving toward the considering public participation data collecting methods.As VGI can act to encourage public participation and empower citizens, mapping agencies could make a partnership with members of the VGI community to help to provide well-structured geospatial data.In this regards, UN-GGIM-AP (United Nations on Global Geospatial Information Management -Asia-Pacific) introduce the idea of a VGI-based GeoPortal (VGI-GeoPortal) to provide cost-effective and real-time disaster-related information through collaboration with the public.* Corresponding author

RELEVANT REVIEWS FOR VGI
With the advent and development of versatile mobile devices and Web-based GIS since 2000's, the general public now demands more geographic information than any other demographic group.With people generating, updating and maintaining their own geographic information voluntarily, the positional quality and logical consistency have been in doubt, which is why the VGI service providers have suggested a number of plans to secure reliability of geographic information.There is no doubt that VGI is drawing more attention than any time in the past, however, thanks to being cost-free, freedom in data use, promptness in use and varied subjects compared to the commercially available data.With the advent of Social Network Services (SNS) and growth of overall web-based environments, VGI not comprise the graphical and property information but also content-oriented data such as texts and images.Representing VGI are Open Street Map(OSM) and Wikimapia.With OSM comprising a variety of sub-tier projects where the user-created maps are based.Mobile-based VGIs are also drawing attention, including the car-navigation application Waze and SNS-based Foursquare service.Variation of VGI data features a variety of subjects from the roadmap data, the base maps of the sub-tier information to POI data, such as popular restaurants, travel information and civil complaints data, video clips and images captured by drones, SNS-based location data, so on and so forth.Generating data on OSM is most common type of VGI which generates itself data by way of: data input onsite; uploading of data provided by the agencies or existing map data; oruser's on-system edit.The data input is subject to onsystem calibration to make up for GPS error or position and property errors.VGI thus features the base maps where satellite video and digital map are provided for accurate calibration and editing.
The following table shows strengths and weaknesses between VGI and current for-profit service.

SYSTEM DESIGN & IMPLEMENTATION OF VGI-GEOPORTAL FOR URBAN FLOOD PREVENTION
For disaster prevention, the government is making systematic efforts to support the execution of public policies that can be used to raise awareness of natural disasters in the community; the general public have to have the opportunity to understand the influences caused by natural disasters; and the community should be leading and active in forming the awareness of the community-based disaster preparation.There are efforts to establish urban flood prevention database through combination of data in various systems promoted by the government and at the same time, user VGI-GeoPortal can be established through the community mapping participated by citizens.
Community mapping is a compound word of 'community' and 'mapping.''Community' indicates all the people who live in a particular area or place and so is a spatial and regional unit of a social organization and in this sense, refers to psychological association or sense of belonging related to such a unit.'Mapping' indicates mapping work.In other words, it connects information to place by making visual expression of the information on geography and space.To combine the two words above into one, 'Community Mapping' can be said as an expression of the common interests by the people who have similar geographical association and sense of belonging into maps.
Figure 1.System structure for VGI-GeoPortal for Disaster Management

Table 1 .
Comparison between VGI and for-profit service