Approximating visibility

@inproceedings{wrf-savannah,
    author = "Franklin, W. Randolph",
    title = "Approximating visibility",
    booktitle = "{GIScience} 2000",
    month = "30 Oct",
    address = "Savannah, Georgia, USA",
    year = "2000",
    mykey = "visviewshedsiting",
    href = "\bibhref{91-savannah-giscience00-appvis}"
}