Tool Name	Threshold Buffer
Tool ID	9
Library ID	grid_tools
Version	1.0
Author(s)	Victor Olaya (c) 2004

Description

This tool performs a feature-buffering operation on a raster layer with additional constraint logic based on a secondary raster input. Unlike standard buffers, it dynamically extends the buffer zone by evaluating each neighboring cell against a user-defined threshold. The extension is conditionally applied based on the values in the secondary raster and can operate in two modes:
- Absolute: compares each neighboring cell's value in the secondary raster directly to the threshold.
- Relative to start cell value: compares each neighboring cell's value relative to the starting cell's value.
Buffer expansion occurs only if the increase or change is within the threshold, allowing for value-sensitive spatial analysis, such as terrain-aware or cost-constrained buffering.

Parameters

Name	Type	Identifier	Description	Constraints
Input
Features	grid, input	FEATURES	Input grid with the features to buffer where valid grid cells are all non-zero, non-NoData values. Cells with a value of 0 or NoData are ignored.
Value	grid, input	VALUE	Secondary input grid with the values used to evaluate the threshold value.
Threshold	grid, input, optional	THRESHOLDGRID	Optional input grid with spatially variable threshold values.
Output
Buffer	grid, output	BUFFER	The buffered output grid. Input features are labelled by 2, buffer zones by 1 and all other cells with 0.
Options
Threshold Value	floating point number	THRESHOLD	The threshold value to apply. Expansion occurs only if the increase or change is within the threshold.	Default: 0.000000
Threshold Type	choice	THRESHOLDTYPE	The mode of operation.	Available Choices: [0] Absolute [1] Relative (to start cell value) Default: 0