Model attributes (Heat Stress Overlay)

The heat overlay's model calculations depend on a number of calculation-wide parameters. These parameters are available as attributes of the heat overlay and can be modified as such.

Icon	Attribute	Unit	Range	Description	Default value
	DAILY_AVG_RADIATION	Wm-2 / hr		The average of amount of sun radiation per hour per square meter for this day, measured at a weather station.	340
	DAILY_AVG_WIND_SPEED	m/s		The daily average wind speed measured at a weather station at the height of 10 meters above ground.	3
	DAILY_TEMPERATURE_MAX	°C		Maximum temperature measured at a weather station.	34
	DAILY_TEMPERATURE_MIN	°C		Minimum temperature measured at a weather station.	19
	DATES	time in milliseconds		Dates define the amount of timeframes and are used to define the day and time for calculating sun angles.	1375444800000
	EXCLUDE_BUILDINGS	boolean		Whether the results of buildings should be excluded from the avg sky-view and PET results.	1
	EXCLUDE_WATER	boolean		Whether the results at the location of water should be excluded from the avg sky-view and PET results.	1
	EXCLUDE_FOLIAGE_HEIGHT_M	m		Whether the area directly below foliage (e.g. Trees higher then this value) should be excluded in calculating the average sky view.	1.2
	FOLIAGE_AREAS	boolean		Whether to use foliage data from Areas instead of the calculated foliage decks from functions with a foliage crown factor.	0
	HOURLY_HUMIDITY	percentage		The relative humidity of the air at this hour, measured at a weather station.	60
	HOURLY_RADIATION	Wm-2 / hr		The amount of Sun radiation this hour, measured at a weather station.	700
	HOURLY_TEMPERATURE	°C		The temperature at this hour, measured at a weather station.	33
	MAX_SHADOW_DISTANCE	m	100 to 1000	The maximum length of a shadow.	500
	SUN_ALTITUDE	angle (0-90°)		The sun angle up from the horizon.	49.71
	SUN_AZIMUTH	geo angle (0-360°)	-1.7976931348623157E308 to 1.7976931348623157E308	The angle of the sun along the horizon.	140.03
	SUN_DAILY_MOTION	factor		A factor to account for the sun moving across the sky throughout the day.	0.11
	WIND_DIRECTION	geo angle (0-360°)	-1.7976931348623157E308 to 1.7976931348623157E308	The wind direction viewed from above, with 0° corresponding to north, and increasing in a clockwise fashion.	0
	WIND_SPEED	m/s		The wind speed measured at a weather station at the height of 10 meters above ground.	3
	WIND_DECLINE_ANGLE	Degrees		This angle determines how the wind flows down around objects.	90

Notes

• The model relies on a number of attributes which can be measured by measure stations. For any given project, it is recommended to find data from a (reference) weather station applicable to the project area, and use those values as parameters for the Heat Module calculations.
• When the DATES attribute is configured for multiple timeframes, the Hourly, Sun, and Wind attributes should have an equal amount of entries. When using the Heat Overlay configuration wizard, the necessary entries are created automatically.

See also

• Weather station (Heat Overlay)

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Heat Stress Module

Heat Stress Module

Tutorials

Overview

Theory

Benchmarks

Group

Model attributes

Model attributes

Daily average radiation • Daily average wind speed • Daily maximum temperature • Daily minimum temperature • Dates • Exclude buildings • Exclude water • Exclude foliage height m • Foliage areas • Hourly humidity • Hourly radiation • Hourly temperature • Max shadow distance • Sun altitude • Sun azimuth • Sun daily motion • Wind direction • Wind speed • Wind decline angle

Building attributes

Bowen ratio • Foliage height • Foliage crown factor • Vegetation fraction

Prequels

Building elevation • Foliage height • Terrain elevation

Related

Calculation models and formulas • Feature attributes • Model attributes • Result types