Combo Overlay

A Combo Overlay, combining a Rainfall Overlay with two Average Overlays (NORMAL and SOCIAL), using only the highest values in the last time frame.

The Combo Overlay is a Grid Overlay which can be used to create additional spatial calculation models. Up to three input Overlays can be selected which serve as input for the calculations. A large set of functions and operators are available which can then perform the desired computations.

Combo Overlays can take any Grid Overlay as input. It is often combined with one or more Average Overlays or Travel Distance Overlays. The Combo Overlay can also use the results of more complex calculation models, such as the Water Overlay or the Heat Overlay to further process the computed results of those models. Finally, Combo Overlays can also refer to other Combo Overlays, to create even more powerful, varied, and complex spatial calculation models.

Operators

In the table below are the operators displayed that are supported by the combo overlay. The term argument refers to a grid overlay configured as input, a numerical value or a global name.

Name	Arguments	Type	Displays
SIN	Single	Function	Sine function
COS	Single	Function	Cosine function
TAN	Single	Function	Tangent function
ASIN	Single	Function	Arc sine function
ACOS	Single	Function	Arc cosine function
ATAN	Single	Function	Arc tangent function
ROUND	Single	Function	Round function
FLOOR	Single	Function	Floor function
CEIL	Single	Function	Ceil function
ABS	Single	Function	Absolute function
EXP	Single	Function	Exponential function
LN	Single	Function	The natural logarithm (base e) function
LOG	Single	Function	The natural logarithm (base 10) function
SQRT	Single	Function	The square root function
RANDOM	Single	Function	The random function, which returns a number greater than or equal to 0.0 and less than the provided argument
ERF	Single	Function	The gauss error function, for probability calculations.
ADD	Multi	Operator	Add one or more argument
MULT	Multi	Operator	Multiply one or more arguments
SUB	Multi	Operator	Subtract one or more arguments from the first argument
DIV	Multi	Operator	Divide the first argument with one or more other arguments
MIN	Multi	Function	Returns the smallest of the provided arguments. That is, the result is the argument closest to negative infinity.
MAX	Multi	Function	Returns the largest of the provided arguments. That is, the result is the argument closest to positive infinity.
AVG	Multi	Function	Returns the arithmetic mean of the provided arguments.
POW	Multi	Function	Raises the first argument to the power of the consecutive arguments. For example 2 to the power 3 to the power 4.
IF	Multi	Function	Takes 3 arguments. If first argument is true (numerical value exactly 1), it returns the second argument, else it returns the third argument.
AND	Multi	Boolean	Returns 1.0 if all arguments are not equal to 0.0.
OR	Multi	Boolean	Returns 1.0 if any argument is not equal to 0.0.
GTE	Pair	Boolean	Returns 1.0 if the first argument is larger than or equal to the second argument, else returns 0.0.
GT	Pair	Boolean	Returns 1.0 if the first argument is larger than the second argument, else returns 0.0.
LTE	Pair	Boolean	Returns 1.0 if the first argument is smaller than or equal to the second argument, else returns 0.0.
LT	Pair	Boolean	Returns 1.0 if the first argument is smaller than the second argument, else returns 0.0.
NEQ	Pair	Boolean	Returns 1.0 if the first argument is not equal to the second argument, else returns 0.0.
EQ	Pair	Boolean	Returns 1.0 if the first argument is equal to second argument, else returns 0.0.
PERCENTILE	Multi	Function	Calculates the linear interpolated k-th percentile (value between 0 and 1) of the sorted array of provided arguments. The last provided argument should be the percentile.
AVG_GTE_PERCENTILE	Multi	Function	Calculates the average of the provided arguments which are above the calculated linear interpolated k-th percentile (value between 0 and 1). The last provided argument should be the percentile.
AVG_LTE_PERCENTILE	Multi	Function	Calculates the average of the provided arguments which are below the calculated linear interpolated k-th percentile (value between 0 and 1). The last provided argument should be the percentile.
SWITCH	Multi	Function	Switch-case function. First argument is the testable expression. Second argument is the default result. Each next pair of 2 arguments is a case value and a result value. When a pair's first argument matches the initial expression, that pair's second argument is returned. If no case matches, the default result is returned.
NO_DATA	Constant	Constant	The NO_DATA value for grid data, indicating no data exists.
DX	Constant	Constant	The cell size in meters of this Combo Overlay.
ITERATION	Constant	Constant	The currently active Iteration

Inputs

• Up to ten Overlays can be configured as input for the Combo Overlay. These prequels are referenced as A, B, C, etc.
• You can use Globals in a formula. This can be done by starting the statement with GLOBAL_. For example a Global named TEST would become: GLOBAL_TEST.

Timeframes

When an input Overlay has multiple Timeframes, additional syntax is available to specify the intended timeframes.

Timeframes are 0-indexed, meaning they start counting at 0. The first timeframe is 0, the second timeframe is 1, the tenth timeframe is 9, etc.

Syntax	Meaning	Example	Effect
A	The (last) value from Overlay A	MUL(A, 10)	Assuming: A is a Water Overlay with Surface Last Value as result type Will show the height of the water at the end of the calculation in cm (rather than m).
A2	The third timeframe's value from Overlay A	GT(A2, 38)	Assuming: A is a Heat Overlay with Physiological Equivalent Temperature as result type Will indicate whether any given location is (1) or is not (0) hotter than 38 °C, on the third computed timeframe of the Heat Overlay.
A0:2	The values from the first through third timeframes from Overlay A, as a list of inputs	AVG(A0:2)	Assuming: A is a Heat Overlay with Physiological Equivalent Temperature as result type Will show the average of the computed temperatures of the first three timeframes of the Heat Overlay.
AT	For each timeframe of the Combo Overlay, the value from that same timeframe from Overlay A, as individual inputs. This will cause the Combo Overlay to have at least as many timeframes as Overlay A.	MUL(AT, 10)	Assuming: A is a Water Overlay with Surface Last Value as result type Will show the height of the water at each timeframe of the Water Overlay's calculations in cm (rather than m).

A Combo Overlay automatically computes the amount of timeframes it requires, based on the following:

• The amount of timeframes of Input Overlays which are referenced in the formula using the T syntax.
• The amount of values in Globals which are referenced in the formula. (Globals are automatically interpreted as a Global array.)

The highest found value among all those dictates the amount of Timeframes the Combo Overlay has.

Examples

• Combo Overlay with average overlays
• Combo Overlay with masking
• Combo Overlay with distance filtering
• How to adjust the height map with a Combo Overlay - an example for kerbs
• How to compute the presence of features of a particular size - an example for public green
• How to combine results of multiple Overlays as timeframes in a Combo Overlay
• How to compute cool locations of sufficient size
• How to make a Grid Overlay of residences

• Conditionally include grid information in Combo Overlay calculation: https://community.tygron.com/forum/discussion/551/conditionally-include-grid-information-in-a-combo-overlay-calculation
• Biodiversity analysis: bats (Dutch only):

Example of the Combo overlay for bat routes in the Tygron Platform. (In Dutch)

Combining geo-information into a bat network in the Tygron Platform. (In Dutch)

Notes

• When multiple input Overlays are referenced with a "T" syntax and those have varying amounts of timeframes, the maximum amount of timeframes among those input Overlays is used.
• When the "T" syntax is used to refer to an input Overlay with fewer timeframes than the Combo Overlay itself, any timeframe referenced via the "T" syntax beyond what the input Overlay offers uses whichever value the last timeframe of that input Overlay had. I.e. if a Water Overlay has 10 timeframes but the Combo Overlay attempts to compute an 11th timeframe and beyond, the value from the last (10th) timeframe of the Water Overlay is used.

How-to's

• How to add and remove an Overlay
• How to edit a Combo Overlay's formula
• How to edit an overlay legend
• How to add and remove an Attribute

Videos

Example of the Combo overlay in the Tygron Platform. (In dutch)

Testing a parametric design on environmental criteria in the Tygron Platform. (In dutch)

See also

• Combo Overlay tutorial

---

Overlays

Categorization

Grid • Parent • Result Child • Result Parent • Result type

Default

City

Administrative

Ownership • Ownership Grid • Zipcodes • Zoning • Neighborhoods • Municipalities • Vacancy

Environmental

Heat Stress • Traffic Density • Traffic Noise • Traffic NO2 • Livability

Water

Rainfall • Flooding • Groundwater • Subsidence • Watershed

Grid Calculation

Average • Combo • Distance • Sight Distance • Travel Distance • Inference • Iteration

Geo Data

GeoTIFF • WCS • WMS • Image • Area • Attribute • Function

Topography

Satellite • Digital Surface Model • Digital Terrain Model • Underground • Source

Network

Network Distance • Network Overview • Network Ownership