WindChill

サマリー

Identifies dangerous winter conditions that, depending on exposure times to the elements, can result in frostbite or hypothermia.

説明

The formula the function uses to compute wind chill is as follows:

``Wind Chill = 35.74 + (0.6215 * T) - (35.75 * WS^0.16) + (0.4275 * T * WS^0.16)``
• T = Air Temperature in degrees Fahrenheit
• WS = Wind speed in miles per hour

The referenced raster dataset for the raster object is temporary. To make it permanent, you can call the raster object's save method.

構文

`WindChill (temperature_raster, wind_speed_raster, {temperature_units}, {wind_speed_units}, {wind_chill_units})`
 パラメーター 説明 データ タイプ temperature_raster[temperature_raster,...] ピクセル値で周辺気温を表すシングルバンド ラスター。 Raster wind_speed_raster[wind_speed_raster,...] A single-band raster where pixel values represent wind speed. Raster temperature_units 入力される温度ラスターに関連付けられる測定単位。 使用できる入力単位は、摂氏度、華氏度、ケルビン度です。(デフォルト値は次のとおりです Fahrenheit) String wind_speed_units Defines the unit of measurement for the wind-speed raster: mph—Miles per hourkm/h—Kilometers per hourm/s—Meters per secondft/s—Feet per secondkn—Knots(デフォルト値は次のとおりです mph) String wind_chill_units 出力ラスターに関連付けられる測定単位。 使用できる出力単位は、摂氏度、華氏度、ケルビン度です。(デフォルト値は次のとおりです Fahrenheit) String

 データ タイプ 説明 Raster The output raster.

コードのサンプル

WindChill example 1

Calculates wind chill based on the temperature and wind speed from the input raster.

``````from arcpy.sa import *
out_windchill_raster = WindChill("temperature.tif", "windspeed.tif", "",
"km/h", "Celsius")
out_windchill_raster.save("C:/arcpyExamples/outputs/wind_chill_C.tif")``````
WindChill example 2

Calculates wind chill based on the temperature and wind speed from the input raster.

``````# Import system modules
import arcpy
from arcpy.sa import *

# Set the analysis environments
arcpy.env.workspace = "C:/arcpyExamples/data"

# Set the local variables
in_temperature_raster = "temperature.tif"
in_wind_speed_raster  = "windspeed.tif"

# Execute WindChill function
out_windchill_raster = WindChill(in_temperature_raster, in_wind_speed_raster,
"", "knots", "Kelvin")
# Save the output
out_windchill_raster.save("C:/arcpyExamples/outputs/wind_chill_K.tif")``````