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  1. Article: A fine-scale spatial population distribution on the High-resolution Gridded Population Surface and application in Alachua County, Florida

    Jia, Peng / Andrea E. Gaughan / Youliang Qiu

    Applied geography. 2014 June, v. 50

    2014  

    Abstract: Geospatial techniques, using Geographic Information Systems and remote sensing data, have become more commonly used with dasymetric modeling of fine-scale demographic data. In this study, we apply a dasymetric approach using the Heuristic Sampling Method ...

    Abstract Geospatial techniques, using Geographic Information Systems and remote sensing data, have become more commonly used with dasymetric modeling of fine-scale demographic data. In this study, we apply a dasymetric approach using the Heuristic Sampling Method for 2010 parcel data to disaggregate population counts from the 2010 U.S. Census into a quadrilateral grid composed of 30 × 30 m cells covering the Alachua County, Florida. The final output, termed the High-resolution Gridded Population Surface (HGPS), is compared to a land cover-based population product (LCPP) and the detail of each product is assessed. Results suggest that the HGPS provides increased spatial heterogeneity and more detail in the boundaries of populated areas over the use of census blocks or land cover lots. For an example of the final output, we use a case study at the Cabot–Koppers Superfund Site to demonstrate the advantages of the HGPS over the LCPP. The HGPS is expected to serve as a more accurate input in various research fields, such as public health, crime analysis, and climate change. The approach outlined provides an improved means of producing spatially-explicit population grids where fine-scale ancillary data, such as parcel data, is available.
    Keywords case studies ; climate change ; crime ; geographic information systems ; geography ; land cover ; models ; population distribution ; public health ; spatial data ; spatial variation ; Florida
    Language English
    Dates of publication 2014-06
    Size p. 99-107.
    Publishing place Elsevier Ltd
    Document type Article
    ISSN 0143-6228
    DOI 10.1016/j.apgeog.2014.02.009
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Application of Object Based Classification and High Resolution Satellite Imagery for Savanna Ecosystem Analysis

    Jane Southworth / Youliang Qiu / Luke Rostant / Sanchayeeta Adhikari / Cerian Gibbes

    Remote Sensing, Vol 2, Iss 12, Pp 2748-

    2010  Volume 2772

    Abstract: Savanna ecosystems are an important component of dryland regions and yet are exceedingly difficult to study using satellite imagery. Savannas are composed are varying amounts of trees, shrubs and grasses and typically traditional classification schemes ... ...

    Abstract Savanna ecosystems are an important component of dryland regions and yet are exceedingly difficult to study using satellite imagery. Savannas are composed are varying amounts of trees, shrubs and grasses and typically traditional classification schemes or vegetation indices cannot differentiate across class type. This research utilizes object based classification (OBC) for a region in Namibia, using IKONOS imagery, to help differentiate tree canopies and therefore woodland savanna, from shrub or grasslands. The methodology involved the identification and isolation of tree canopies within the imagery and the creation of tree polygon layers had an overall accuracy of 84%. In addition, the results were scaled up to a corresponding Landsat image of the same region, and the OBC results compared to corresponding pixel values of NDVI. The results were not compelling, indicating once more the problems of these traditional image analysis techniques for savanna ecosystems. Overall, the use of the OBC holds great promise for this ecosystem and could be utilized more frequently in studies of vegetation structure.
    Keywords savannas ; vegetation structure ; tree canopies ; object based ; IKONOS ; Science ; Q
    Subject code 710
    Language English
    Publishing date 2010-12-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Roads as Drivers of Change

    Grenville Barnes / Forrest Stevens / Amy Duchelle / Karla Rocha / Graeme Cumming / Youliang Qiu / Jane Southworth / Stephen Perz / Matt Marsik

    Remote Sensing, Vol 3, Iss 5, Pp 1047-

    Trajectories across the Tri‑National Frontier in MAP, the Southwestern Amazon

    2011  Volume 1066

    Abstract: Regional studies of land cover change are often limited by available data and in terms of comparability across regions, by the transferability of methods. This research addresses the role of roads and infrastructure improvements across a tri-national ... ...

    Abstract Regional studies of land cover change are often limited by available data and in terms of comparability across regions, by the transferability of methods. This research addresses the role of roads and infrastructure improvements across a tri-national frontier region with similar climatic and biophysical conditions but very different trajectories of forest clearing. The standardization of methodologies and the extensive spatial and temporal framework of the analysis are exciting as they allow us to monitor a dynamic region with global significance as it enters an era of increased road connectivity and massive potential forest loss. Our study region is the “MAP” frontier, which covers Madre de Dios in Peru, Acre in Brazil, and Pando in Bolivia. This tri-national frontier is being integrated into the global economy via the paving of the Inter-Oceanic Highway which links the region to ports in the Atlantic and Pacific, constituting a major infrastructure change within just the last decade. Notably, there are differences in the extent of road paving among the three sides of the tri-national frontier, with paving complete in Acre, underway in Madre de Dios, and incipient in Pando. Through a multi-temporal analysis of land cover in the MAP region from 1986 to 2005, we found that rates of deforestation differ across the MAP frontier, with higher rates in Acre, followed by Madre de Dios and the lowest rates in Pando, although the dominant land cover across the region is still stable forest cover (89% overall). For all dates in the study period, deforestation rates drop with distance from major roads although the distance before this drop off appears to relate to development, with Acre influencing forests up to around 45 km out, Madre de Dios to about 18 km out and less of a discernable effect or distance value in Pando. As development occurs, the converted forest areas saturate close to roads, resulting in increasing rates of deforestation at further distances and patch consolidation of clearings over time. We can use ...
    Keywords MAP ; deforestation ; connectivity ; infrastructure ; roads ; Science ; Q
    Subject code 910
    Language English
    Publishing date 2011-05-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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