List of Combo Overlay examples

Attribute

Solid Buildings

The attribute SOLID generally has a value of 0 or 1. It can therefore be used directly in a Combo Overlay Formula.

Set Combo Maplink to BUILDINGS
Set Key A to SOLID
Set Formula to:
```
@A
```

Residential Buildings

The unit size category values can be used to identify and rasterize residences, in combination with a GT (Greater than) function with multiple arguments. To setup:

Set Combo Rasterization to "Attribute:Specific Layer" (SINGLE_LAYER)
Set Combo Maplink to Buildings
Set Key A to SOCIAL_UNIT_SIZE_M2
Set Key B to NORMAL_UNIT_SIZE_M2
Set Key C to LUXE_UNIT_SIZE_M2
Set Key D to STUDENT_UNIT_SIZE_M2
Set Key E to SENIOR_UNIT_SIZE_M2
Set Formula to:
```
GT(@A,@B,@C,@D,@E)
```

Categorized Residential Buildings

The unit size category values can be used to identify and rasterize residence types, in combination with a IF and GT (Greater than) functions with multiple arguments. We will categorize the residential buildings as followed: SOCIAL (1) , NORMAL (2), LUXE (3), SENIOR (4), STUDENT (5) and everything else 0.

To setup:

Set Combo Rasterization to "Attribute:Specific Layer" (SINGLE_LAYER)
Set Combo Maplink to Buildings
Set Key A to SOCIAL_UNIT_SIZE_M2
Set Key B to NORMAL_UNIT_SIZE_M2
Set Key C to LUXE_UNIT_SIZE_M2
Set Key D to SENIOR_UNIT_SIZE_M2
Set Key E to STUDENT_UNIT_SIZE_M2

Set Formula to:

IF(GT(@A,0),1,IF(GT(@B,0),2,IF(GT(@C,0),3, IF(GT(@D,0), 4, IF(GT(@E,0),5,0))))

Switch

Categorization using Base Types

For water balance analyses of calculated Water Overlays, it can be useful to split rainfall on land and rainfall on shorelines and water. We can use switch on the Base type result type (Water Overlay) and include a Rainfall result accordingly. For water on land, we can use the following setup:

Set Grid A to the Rainfall result type of a Water Overlay.
Set Grid B to the Base Typology result type of a Water Overlay.

Set Formula to;

SWITCH(BT, 0, 0, AT, 1, AT, 2, 0, 3, 0, 4, AT, 5, 0, 6, 0, 7, 0, 8, AT, 9, 0, 10, AT, 11, 0, 12, 0, 13, AT, 14, AT, 15, 0, 16, 0, 17, AT, 18, AT)

For water on waterways and shorelines, use the same setup but adjust the formula to:

SWITCH(BT, 0, 0, 0, 1, 0, 2, AT, 3, AT, 4, 0, 5, AT, 6, AT, 7, AT, 8, 0, 9, AT, 10, 0, 11, AT, 12, AT, 13, 0, 14, 0, 15, AT, 16, AT, 17, 0, 18, 0)

Tip: For other result type splits, adjust the Grid A to a different Water Overlay result type, such as evaporation.

Rasterization

Minimum infiltration among layers

An example on how the combo overlay can obtain rasterized data from multiple data layers (MapLinks); Terrains, Buildings, Neighborhoods, Areas and Zones.

Set Combo Rasterization to "Attribute:Min value" (MIN)
Set Combo Maplink to nothing (null)
Set Key A to GROUND_INFILTRATION_MD
Set Formula to:
```
@A
```

Timeframes

Minimum value among timeframes

An example on how the Combo Overlay can calculate the minimum value among timeframes of a Prequel Grid Overlay

Set A prequel (Combo Overlay) to the Grid Overlay (with 10 timeframes).
Set Formula to:
```
MIN(A0:9)
```

Maximum value among timeframes

An example on how the Combo Overlay can calculate the maximum value among timeframes of a Prequel Grid Overlay

Set A prequel (Combo Overlay) to the Grid Overlay (with 10 timeframes).
Set Formula to:
```
MAX(A0:9)
```

Average value among timeframes

An example on how the Combo Overlay can calculate the average value among timeframes of a Prequel Grid Overlay, for example a Shadow Overlay:

Set A prequel (Combo Overlay) to the Grid Overlay (with 10 timeframes).
Set Formula to:
```
AVG(A0:9)
```

Mask for each timeframe

An example on how the Combo Overlay can calculate, for each timeframe of an input overlay, whether a grid value is above a specific value. In this example a Heat Stress Overlay with a minimum value of 45 degrees.

Set A prequel (Combo Overlay) to a Grid Overlay, in this example a Heat Stress Overlay.
Set Formula to:
```
IF(GT(AT, 45), 1, 0)
```

Filter each timeframe

An example on how the Combo Overlay can calculate, for each timeframe of an input overlay, only include a grid value when it is above a specific value, and make it NO_DATA otherwise. In this example a Heat Stress Overlay with a minimum value of 45 degrees.

Set A prequel (Combo Overlay) to a Grid Overlay, in this example a Heat Stress Overlay.
Set Formula to:
```
IF(GT(AT, 45), AT, NO_DATA)
```

Iteration

For initializing a Combo Overlay in a iteration setup, the ITERATION parameter can be used to obtain the active Iteration number. In this example we initialize the value to 0.

Set Grid A to a calculated Grid Overlay during the iterated simulation. For example a Surface last value result type (Water Overlay)
Set Grid B to a Grid Overlay used for initialization values.

Set Formula to:

IF(EQ(ITERATION, 0), IF(EQ(B, NO_DATA), 5, B), A)

Colors

Grid input to colors

An example on how a combo overlay can return a complex colorization using a grid input without using a legend. This example expects the value of an input Grid Overlay to be:

Negative or NO_DATA in case it has no direction
A value between 0 and 360 indicating a direction.

Configure the Combo Overlay as followed:

Set Grid A to an input overlay representing a direction in degrees, such as Surface avg direction result type (Water Overlay)

Set Formula to:

IF(OR(LT(AT, 0), EQ(NO_DATA, AT)), NO_DATA, IF(LT(AT, 15), COLOR(255, 0), IF(LT(AT, 45), COLOR(255, 125, 0), IF(LT(AT, 75), COLOR(255, 255, 0), IF(LT(AT, 105), COLOR(125, 255, 0), IF(LT(AT, 135), COLOR(0, 255, 0), IF(LT(AT, 165), COLOR(0, 255, 125), IF(LT(AT, 195), COLOR(0, 255, 255), IF(LT(AT, 225), COLOR(0, 125, 255), IF(LT(AT, 255), COLOR(0, 0, 255), IF(LT(AT, 285), COLOR(125, 0, 255), IF(LT(AT, 315), COLOR(225, 0, 225), IF(LT(AT, 345), COLOR(225, 0, 125), COLOR(255, 0, 0))))))))))))))

Saturate Satellite Imagery

The satellite imagery colors can be saturated using a saturation approximation function. In this example the factor is set to 0.9. Attributes are stored in the Combo Overlay and used in the formula with the prefix GLOBAL_

Set Grid A to a Satellite Overlay
Add Global named R_FACTOR with value 0.2989
Add Global named G_FACTOR with value 0.587
Add Global named B_FACTOR with value 0.114
Add Global named SATURATION with value 0.9

Set Formula to:

COLOR(
 ADD(MUL(-1, GLOBAL_SATURATION, 
  ADD(MUL(GLOBAL_R_FACTOR, RED(A)), MUL(GLOBAL_G_FACTOR, GREEN(A)), MUL(GLOBAL_B_FACTOR, BLUE(A)))), MUL(ADD(1, GLOBAL_SATURATION), RED(A))), 
 ADD(MUL(-1, GLOBAL_SATURATION, 
  ADD(MUL(GLOBAL_R_FACTOR, RED(A)), MUL(GLOBAL_G_FACTOR, GREEN(A)), MUL(GLOBAL_B_FACTOR, BLUE(A)))), MUL(ADD(1, GLOBAL_SATURATION), GREEN(A))), 
 ADD(MUL(-1, GLOBAL_SATURATION, 
  ADD(MUL(GLOBAL_R_FACTOR, RED(A)), MUL(GLOBAL_G_FACTOR, GREEN(A)), MUL(GLOBAL_B_FACTOR, BLUE(A)))), MUL(ADD(1, GLOBAL_SATURATION), BLUE(A)))
)

The factors for red, green and blue are based on YCbRc ITU-R BT.601 conversion^[1].

References

↑ YCbRc ITU-R BT.601 conversion ∙ Found at: https://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion ∙ (last visited: 2026-06-30)

[ref-YCbRcConversion-1] YCbRc ITU-R BT.601 conversion ∙ Found at: https://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion ∙ (last visited: 2026-06-30)

[1]

List of Combo Overlay examples

Contents

Attribute

Solid Buildings

Residential Buildings

Categorized Residential Buildings

Switch

Categorization using Base Types

Rasterization

Minimum infiltration among layers

Timeframes

Minimum value among timeframes

Maximum value among timeframes

Average value among timeframes

Mask for each timeframe

Filter each timeframe

Iteration

Colors

Grid input to colors

Saturate Satellite Imagery

See also

References

Navigation menu

List of Combo Overlay examples

Attribute

Solid Buildings

Residential Buildings

Categorized Residential Buildings

Switch

Categorization using Base Types

Rasterization

Minimum infiltration among layers

Timeframes

Minimum value among timeframes

Maximum value among timeframes

Average value among timeframes

Mask for each timeframe

Filter each timeframe

Iteration

Colors

Grid input to colors

Saturate Satellite Imagery

See also

References

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