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Converting a NEXRAD Rainfall Map into a Flood Inundation Map by ...

Converting a NEXRAD Rainfall Map into a Flood Inundation Map by ...

Converting a NEXRAD Rainfall Map into a Flood Inundation Map by ...

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Int OperationThe Integer operation is needed to generate an integer value raster toenable the implementation of the “Raster to Polygon” tool. This tool does notaffect the level of precision of the final result since the required output (at leastfor the current implementation) is represented <strong>by</strong> a single polygon of inundatedarea that does not contain any internal discretization of water depth values in thefloodplain.Raster to Polygon OperationThe Raster to Polygon tool transforms the water depth raster surface <strong>into</strong> agridded polygon corresponding to the vector representation of the water depthraster. The outcome of this tool is a polygon feature composed of multiple squarepolygons representing the raster cells and having the water depth values populatedon each polygon.Dissolve OperationThe Dissolve function dissolves the multiple inundated polygons toproduce a single polygon representing the entire inundated area of the floodplainunder study with no discrimination for water depth values (just water depthsgreater than zero).Another alternative to accomplish the floodplain delineation consists ofreplacing the final Dissolve geoprocessing operation with the Reclassify operationoccurring prior to the “Raster to Polygon” geoprocess.The “Reclassify” operation is used to reclassify the class value intervals ofthe integer water depth raster with a single common value for the whole surface175

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