1. Online real-time tweets extraction, mapping and dissemination Xiannian Chen and Gregory Elmes West Virginia University Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV1

2. Geospatial data Challenges that geospatial data face Traditional geospatial data updates are slow. The real-time data is critical in disaster management. Crowdsourcing (Jeff Howe 2005, Brabham 2008) VGI ( Volunteered Geographic Information, Goodchild 2007 ) Real time geographic information from volunteers “geographic information acquired and made available to others through the voluntary activity of individuals or groups, with the intent of providing information about the geographic world” (Elwood, Goodchild, and Sui 2011) Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV2

3. Values of VGI Captures of real time changes Quick dissemination A significant data source. Individuals’ understandings of a local event Rich in context Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV3

4. API and REST Application Programming Interface A library that may include specification for routines, data structures, object classes, and variables An interface for software components to communicate All social media websites provide API REST (REpresentational State Transfer, Fielding 2000) A HTTP-based style to describe the resources it represents. uses HTTP for all four CRUD (Create/Read/Update/Delete) The access of REST services is a simple URL Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV4

5. Twitter and Tweets Twitter: a real-time information network Tweets created_at coordinates favorite_count, retweet_count id place text user more information: https://dev.twitter.com/docs/platform-objects/tweets https://dev.twitter.com/docs/platform-objects/tweets Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV5

6. Twitter Search API Twitter provides REST API to access tweets The resources are represented in RESTful style, which mean, in theory, users can get tweets by typing the URL with right parameters. Tweets, especially geo-tagged tweets A sample URL for query: https://api.twitter.com/1.1/search/tweets.json?q=shooting&geocode =41.148693,-81.346292,100km&result_type=recent&until=2014- 05-30&since=2014-05-29&count=100 Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV6

7. Major query parameters q – the search keywords geocode – location with radius. Format: lat, long, 50mi. since, until – the search time frame. Format: yyyy-mm-dd count – the number of tweet in a query. <100 result_type – types of search results preferred to receive mixed: Include both popular and real time results in the response. recent: return only the most recent results in the response. popular: return only the most popular results in the response. more information: https://dev.twitter.com/docs/api/1.1/get/search/tweets https://dev.twitter.com/docs/api/1.1/get/search/tweets Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV7

8. Authorization Required in Twitter API v1.1. Response of un-authorized request. {"errors":[{"message":"Bad Authentication data","code":215}]} Using Twitter website to generate the authorization code API key API secret Access token Access token secret Use and activate authorization through server-side programming technologies, e.g. PHP, Python. Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV8

9. System architecture for live VGI saving Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV9

10. Implementation of live data saving Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV10

11. A live demo http://157.182.212.204/tweets Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV11

12. Issues Quality Accuracy Uncertainty Credibility Heterogeneities Liability Privacy Confidentiality Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV12

13. Chen & Elmes @ West Virginia University2014 WVAGP GIS Conference, Charleston, WV13 Thanks and questions