GLI Map Creator

For more on what GLI is and how it is calculated, see here.

Parameters for this behavior

Parameter name	Description
Height at Which GLI is Calculated for GLI Map, in meters	Height at which GLI is calculated.
Minimum Solar Angle for GLI Map Creator, in rad	This is the minimum angle at which sunlight is seen, in radians. Below this value the sky is assumed to be dark due to shading neighbors.
Number of Altitude Sky Divisions for GLI Map Creator Calculations	Number of grid cells into which the sky is divided from horizon to zenith, for the purpose of calculating light direction.
Number of Azimuth Sky Divisions for GLI Map Creator Calculations	Number of grid cells into which the sky is divided around the horizon, for the purpose of calculating light direction.

General light parameters used by this behavior

Parameter name	Description
Beam Fraction of Global Radiation	The fraction of total solar radiation that is direct beam radiation (as opposed to diffuse). Expressed as a value between 0 and 1.
Clear Sky Transmission Coefficient	Used to determine the amount of solar radiation seen at the plot location.
First Day of Growing Season	The first day of the growing season, as a Julian day (number between 1 and 365). Trees only get light during the growing season.
Last Day of Growing Season	The last day of the growing season, as a Julian day (number between 1 and 365). Trees only get light during the growing season.
Amount Canopy Light Transmission (0-1)	Fraction of light transmitted through the tree crown for each species. Expressed as a fraction between 0 and 1. A value must be provided for all species, even if they don't all use light.
Snag Age Class 1 Amount Canopy Light Transmission (0-1)	Fraction of light transmitted through the snag tree crown for each species. Applies to those snags whose age is less than or equal to "Upper Age (Yrs) of Snag Light Transmission Class 1". Expressed as a fraction between 0 and 1. If your run does not work with snags, you can ignore this. Otherwise, a value must be provided for all species.
Snag Age Class 2 Amount Canopy Light Transmission (0-1)	Fraction of light transmitted through the snag tree crown for each species. Applies to those snags whose age is greater than "Upper Age (Yrs) of Snag Light Transmission Class 1", but is less than or equal to "Upper Age (Yrs) of Snag Light Transmission Class 2". Expressed as a fraction between 0 and 1. If your run does not work with snags, you can ignore this. Otherwise, a value must be provided for all species.
Snag Age Class 3 Amount Canopy Light Transmission (0-1)	Fraction of light transmitted through the snag tree crown for each species. Applies to those snags whose age is greater than "Upper Age (Yrs) of Snag Light Transmission Class 2". Expressed as a fraction between 0 and 1. If your run does not work with snags, you can ignore this. Otherwise, a value must be provided for all species.
Upper Age (Yrs) of Snag Light Transmission Class 1	The upper age limit, in years, defining the first age class of snag light transmission. Snags with an age less than or equal to this age have a light transmission coefficient matching "Snag Age Class 1 Light Transmission Coefficient". If your run does not work with snags, you can ignore this.
Upper Age (Yrs) of Snag Light Transmission Class 2	The upper age limit, in years, defining the second age class of snag light transmission. Snags with an age greater than the upper limit for size class 1, but less than or equal to this age, have a light transmission coefficient matching "Snag Age Class 2 Light Transmission Coefficient". Snags with an age greater than this value are in age class three. If your run does not work with snags, you can ignore this.

How it works

This behavior calculates a GLI value for each cell in a grid object called GLI Map [X], where [X] is the position of this behavior in the run (the only significance of this number is to distinguish it from other copies of the same grid). The height at which this GLI value is calculated is set by the Height at Which GLI is Calculated for GLI Map, in meters parameter. These values are not used by any other behavior. You can save the values in the GLI Map grid into a detailed output file and view the map data later.

How to apply it

Add the behavior to the run. Be sure to save the GLI Map grid in the detailed output file in order to be able to view the results. You can add more than one of these behaviors to a run to generate multiple maps. The grids will be distinguished by the number at the end of the name.