List of Combo Overlay examples: Difference between revisions
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*Set Formula to:<syntaxhighlight copy>MAX(0,SUB(A, B))</syntaxhighlight> | *Set Formula to:<syntaxhighlight copy>MAX(0,SUB(A, B))</syntaxhighlight> | ||
===Residential Facades=== | |||
An example on how to calculate facades with a Combo Overlay using variants of the Heightmap Overlay and Building attributes. | |||
*Set [[A prequel (Combo Overlay)|Grid A]] to a [[Heightmap Overlay]] set to the [[DTM|DTM result type]] | |||
*Set [[B prequel (Combo Overlay)|Grid B]] to a [[Heightmap Overlay]] set to the [[DSM|DSM result type]] | |||
*Set [[C prequel (Combo Overlay)|Grid C]] to an [[Average Overlay]], with an [[Distance m (Average Overlay)|Average distance]] of 3 meter and the [[DSM]] as | |||
*Set [[D prequel (Combo OVerlay)|Grid D]] to an [[Average Overlay]], with an [[Distance m (Average Overlay)|Average distance]] of 3 meter and a [[Input prequel (Average Overlay)|Grid Input]] based on the [[#Residential Buildings|Residential Combo Overlay]] | |||
*Set Formula to:<syntaxhighlight copy>AND(GT(SUB(C, A), 1), GT(SUB(C, B), 1), GT(D, 0))</syntaxhighlight> | |||
===Water Level Area Validation=== | ===Water Level Area Validation=== | ||
Revision as of 15:34, 1 July 2026
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.
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))))
Grid
Relative Height Map
To calculate a Relative Height Map, the following Combo Overlay setup can be used. In this example we only want positive relative heights.
- Set A prequel (Combo Overlay) to a Grid Overlay representing the Digital surface model, in this example a WCS Overlay.
- Set B prequel (Combo Overlay) to a Heightmap Overlay set to the DTM result type
- Set Formula to:
MAX(0,SUB(A, B))
Residential Facades
An example on how to calculate facades with a Combo Overlay using variants of the Heightmap Overlay and Building attributes.
- Set Grid A to a Heightmap Overlay set to the DTM result type
- Set Grid B to a Heightmap Overlay set to the DSM result type
- Set Grid C to an Average Overlay, with an Average distance of 3 meter and the DSM as
- Set Grid D to an Average Overlay, with an Average distance of 3 meter and a Grid Input based on the Residential Combo Overlay
- Set Formula to:
AND(GT(SUB(C, A), 1), GT(SUB(C, B), 1), GT(D, 0))
Water Level Area Validation
When initializing water levels for a Water Overlay using Water Level Areas, it might be useful to verify where the water level is within reasonable distance compared to the Digital Terrain Model. In this example we use the attribute named WATER_LEVEL for the datum height of Water Levels. Secondly, the Water Level is only checked for Water Terrain and should be between 0 and 4 meters above the Digital Terrain Model. The threshold for whether rasterized terrain is water, is set to 0.5. Setup:
- Set Combo Rasterization to "Attribute:First"
- Set Combo Maplink to nothing (null)
- Set Key A to WATER_LEVEL
- Set Key B to WATER
- Set Grid A to the Heightmap Overlay
- Set Formula to:
IF(GT(@B, 0.5), AND(LT(SUB(@A, A), 4), GT(SUB(@A, A), 0)), NO_DATA)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 5.
- 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)
Inference
Inference Analysis
You can validate the effectiveness of a trained RCNN using an Inference Overlay by comparing its recognized features with manually drawn features (using Areas with a particular Attribute) and perform Intersection over Union calculations. It can also be useful to visualize regions where features were recognized but not drawn manually, and vice versa. You can use the following setup to do these analyses. In this example we will use a RCNN for recognizing foliage, and have drawn Areas manually and assigned the attribute FOLIAGE to them. Base setup:
- Set Combo Rasterization to "Attribute:Specific Layer" (SINGLE_LAYER)
- Set Combo Maplink to Areas
- Set Key A to FOLIAGE
- Set Grid A to the Inference Overlay, setup for Foliage detection.
- Set Function to:
Union:
OR(GT(A, 0), GT(@A, 0))Intersection:
AND(GT(A, 0), GT(@A, 0))Missing Manual:
AND(GT(A, 0), LTE(@A, 0))Missing Inference:
AND(LTE(A, 0), GT(@A, 0))Foliage Height
To create an Overlay that represents an estimated foliage height, you can use the following setup. In this example we only include foliage larger than 1 meter, and we multiply the foliage height by a factor of 1.2 due to the measurement accuracy of the Digital Surface Model service. Setup:
- Set Grid A to the WCS Overlay, setup for a Digital Surface Model service.
- Set Grid B to the Heightmap Overlay with DTM result type.
- Set Grid C to the Inference Overlay, setup for Foliage detection.
IF(AND(GT(C, 0), GT(SUB(A, B), 1)), MULT(1.1, SUB(A, B)), NO_DATA)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_FACTORwith value 0.2989 - Add Global named
G_FACTORwith value 0.587 - Add Global named
B_FACTORwith value 0.114 - Add Global named
SATURATIONwith 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].
Color Filtering
For feature recognition using Inference Overlays with RCNNs, it might be useful to narrow the space for recognition by making parts of the satellite imagery black where it is not needed. This can be used for both for the initial training and test data, as well as direct input for Inference Overlays. In this example, we are interested in gardens of residential areas that are marked as private yards.
- Set Combo Rasterization to "Attribute:Specific Layer" (SINGLE_LAYER)
- Set Combo Maplink to Buildings
- Set Key A to PRIVATE_YARD
- Set Grid A to a Satellite Overlay.
- Set Formula to:
IF(@A, A, COLOR(0, 0, 0))
See also
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)