WindChill

概要

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

ディスカッション

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

For more information about how this function works, see the Wind Chill raster function.

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 hour km/h —Kilometers per hour m/s —Meters per second ft/s —Feet per second kn —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

戻り値

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")