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941.
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Polyan PM 《Soviet geography》1982,23(10):707-718
The study of urban agglomerations in the USSR is discussed, with a focus on their basic framework and role in settlement and on the various techniques used to define such agglomerations. "The present paper envisages a minimum population of 250,000 for the core city (or cities), maximum travel time of 1.5 to 2 hours to the core city, and a minimum value for a 'development coefficient' reflecting the population of the agglomeration and its structure in terms of urban places. The networks of agglomerations that existed at the time of the 1959 and 1970 censuses are analyzed and compared. The urban agglomerations are grouped into five classes of development levels and into three classes of growth rates. Intensive and extensive growth factors are discussed." 相似文献
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Richard M. Smith 《The Professional geographer》1986,38(1):62-67
The most common goal when classing data for choropleth maps is to create homogeneous classes which contain similar data values. None of the four traditional data classing methods examined here (quartile, equal interval, standard deviation, and natural breaks) consistently generalized the experimental data sets into homogeneous classes. These methods were most accurate for data sets with specific distributional characteristics, but none classed all of any type of distribution accurately. Only the optimization method produced reliable and accurate results for all of the experimental data. 相似文献
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Robert S. Webb Jonathan T. Overpeck David M. Anderson Bruce A. Bauer Mildred K. England Wendy S. Gross E. Ann Meyers Michael M. Worobec 《Journal of Paleolimnology》1993,9(1):69-75
Conclusion The World Data Center-A for Paleoclimatology, located in the NOAA/NGDC Paleoclimatology Program, is committed to providing the scientific community with easy access to all paleoenvironmental data. Efforts to make archived data readily available include international coordination of data acquisition, management, and distribution, sponsoring workshops and data cooperatives to facilitate the compilation of important data sets, development of a browse and visualization software package (PaleoVu), and dispersal of archived data on magnetic media or over ANONYMOUS FTP/INTERNET. The program publishes a semi-annual newsletter that highlights latest developments and accomplishments in the area of paleoenvironmental data for global change research. Contributions to the newsletter are welcome from researchers describing their efforts to coordinate the free flow of paleoclimate data throughout the international scientific community.For information on the program or to be added to the mailing list contact Mrs Mildred England (phone: 303-497-6227; Fax: 303 497-6513; e-mail: MKE@mail.ngdc.noaa.gov), NOAA National Geophysical Data Center, Paleoclimatology Program/World Data Center-A for Paleoclimatology, 325 Broadway, E/GC Boulder, CO 80303 USA 相似文献