Important! Be deliberate in the rules you apply when editing landscapes:
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Rules are applied based on the order in which you add them.
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A specific attribute for a given cell can only be changed once per editing session.
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Selection criteria cannot be contingent on another change that is being made in the same editing session.
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Each attribute is treated separately when applying User Created Edit rules. Editing one attribute, for example fuel model, does not change other attributes, such as canopy cover. Similarly, editing one attribute does not prevent the other attributes from being edited.
Always validate your new landscape to ensure the changes made are what you intended. If you are unsure of the effect of the rules you apply, consider saving a version of your landscape after each edit to allow for easy comparison of the changes made by each edit rule you apply.
For further detail see the Rule Ordering Considerations topic.
User Created Edit rules are used to change one or more features of landscape based upon criteria you specify. To aid in this process, each available choice is described in detail in this topic.
Edit Rule Terminology
Operator: The math that will be applied to each pixel to change the selected pixels.
Modifier: The parameter that the pixel value will change according to.
Attribute: The characteristic of the landscape (elevation, slope, aspect, fuel model, canopy cover, etc.).
Value: User-specific number that operators and modifiers will select pixels or change pixel values according to.
Operators
| Operator | Function | Example |
|---|---|---|
| Is equal to | Identifies all pixels which have the attribute that equals the specified value | Elevation (Attribute) is equal to (Operator) 3500 (Value) feet Is less than |
| Is less than | Identifies all pixels which have the attribute that is less than (but does not include) the specified value | Elevation (Attribute) is less than (Operator) 3500 (Value) feet |
| Is greater than | Identifies all pixels which have the attribute that is greater than (but does not include) the specified value | Elevation (Attribute) is greater than (Operator) 3500 (Value) feet |
| Is less than or equal to | Identifies all pixels which have the attribute that is less than or equal to (does include) the specified value | Elevation (Attribute) is less than or equal to (Operator) 3500(Value) feet |
| Is greater than or equal to | Identifies all pixels which have the attribute that is greater than or equal to (does include) the specified value | Elevation (Attribute) is greater than or equal to (Operator) 3500(Value) feet |
Modifiers
| Modifer | Function | Example |
|---|---|---|
| Set to | Modifies all pixels which are identified by the operator, so they are set to the specified value | Canopy Cover (Attribute) is Set to (Modifier) 30 (Value) percent |
| Clamp to minimum | Modifies all pixels which are identified by the operator, so they clamp to minimum (only changes the values that fall below that minimum) specified value | Canopy Cover (Attribute) will Clamp to minimum of (Modifier) 30 (Value) percent |
| Clamp to maximum | Modifies all pixels which are identified by the operator, so they clamp to maximum (only changes the values that fall above that maximum) specified value | Canopy Cover (Attribute) will Clamp to maximum of (Modifier) 30 (Value) percent |
| Multiply by | Modifies all pixels which are identified by the operator, so they are multiplied by the specified value | Canopy Cover (Attribute) will Multiply by (Modifier) 2 (Value) |
| Increase by | Modifies all pixels which are identified by the operator, so they are increased by the specified value | Canopy Cover (Attribute) will Increase by (Modifier) 30 (Value) percent |
| Decrease by | Modifies all pixels which are identified by the operator, so they are decreased by the specified value | Canopy Cover (Attribute) will Decrease by (Modifier) 30 (Value) percent |
| Clear value (set to no data) | Modifies all pixels which are identified by the operator, so the existing value is cleared and set to no data. | All pixel values for attribute will have no value based on operator selection. |
Notes
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Modifier attributes do not include topography, you cannot change topography (elevation, slope, and aspect).
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Multiply by modifier will increase attribute when multiplying by a positive number and will decrease an attribute when multiplied by a decimal fraction (25 x 0.5 = 12.5).
