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Physical and Environmental Geography Commons

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Full-Text Articles in Physical and Environmental Geography

Evaluating Relevance And Reliability Of Twitter Data For Risk Communication, Xiaohui Liu Aug 2017

Evaluating Relevance And Reliability Of Twitter Data For Risk Communication, Xiaohui Liu

Dissertations

While Twitter has been touted to provide up-to-date information about hazard events, the relevance and reliability of tweets is yet to be tested. This research examined the relevance and reliability of risk information extracted from Twitter during the 2013 Colorado floods using five different approaches. The first approach examined the relationship between tweet volume and precipitation amount. The second approach explored the relationship between geo-tagged tweets and degree of damage. In the third approach, the spatiotemporal distribution of tweets was compared with flood extent. In the fourth approach, risk information from tweets were compared with survey responses obtained in a …


Textural Analysis Of Historical Aerial Photography To Determine Change In Coastal Marsh Extent: Site Of The Present-Day Grand Bay National Estuarine Research Reserve (Gbnerr), Mississippi, 1955-2014, Heather Michelle Nicholson Aug 2017

Textural Analysis Of Historical Aerial Photography To Determine Change In Coastal Marsh Extent: Site Of The Present-Day Grand Bay National Estuarine Research Reserve (Gbnerr), Mississippi, 1955-2014, Heather Michelle Nicholson

Master's Theses

Coastal marshlands are among the world’s most highly productive ecosystems but they have diminished greatly in the past several decades owing to sea-level rise and direct anthropogenic influences. An effective means of quantifying loss or gain in marsh area is through the use of aerial image data, which offers synoptic views of the landscape at decadal-scale sampling frequencies. However, a potential problem with older panchromatic, or black-and-white, imagery is the absence of multispectral information that might be used otherwise in remote identification of vegetation types. Nevertheless, the analysis of horizontal variability in image brightness values, or image texture, can be …