用V-I-S模式描述都市土地覆蓋：以猶他州鹽湖城為例

Describing Urban Land Covers Using the V-I-S (Vegetation-Impervious Surface-Soil) Model : Modeling Salt Lake City, Utah Metropolitan Area

都市地區的土地覆蓋物是多樣的，這使得都市地區在空間上及光譜上非常的異質化，也使得都市地區的環境模式化非常困難．借助於既有的V-I-S（Vegetation植生,Impervioussurface不透水表面，Soil土壤）模式及軟分類法，都市地區能夠被簡化成三種基本物質的組成，而這種簡化使得都市地區能夠被數值化描述及分析．在這篇文章裡，多種具有代表性的都市特徵將逐一被檢視，這些都市特徵的V-I-S組成會被數值化性得展示在不同的表格及圖形，這種數值化資料提供了不同土地覆蓋或土地利用比較的基礎．此外，多條空間剖面從市中心向外延伸到都市週遭地區也顯示了V-I-S組成因地而異，但也都遵循著一個共同趨勢：從市中心到郊區，不透水表面會遞減，而植生會遞增。

A great diversity of land cover types is present in urban areas. This diversity makes urban areas spatially and spectrally heterogeneous, and in turn makes urban environmental modeling challenging. With an urban land cover based model, the V-I-S (Vegetation-Impervious surface-Soil) model, and a previously developed soft classifier, urban environments could be simplified and therefore represented as combinations of three basic urban components. With this simplification, urban environments could be described and analyzed quantitatively. Typical urban features were selected. The V-I-S compositions of these selected urban features are shown in a quantitative manner by various forms, such as tables, plots, feature space plots, and the V-I-S diagrams. This quantitative data provide bases for comparisons between different land cover/use types. In addition, spatial profiles are also drawn from the downtown area towards city boundaries to show the general trends of change in land cover composition across an urban landscape. As expected, impervious surface general decreases as one moving towards city boundaries, while vegetation or soil increases.