Raster Frequency Analysis by Constant
Overview
This tool calculates, for each cell location, how many input raster values meet a specified comparison condition against a constant value.
How It Works
The tool compares each input raster cell value with the constant value and writes the count of matching values to the output raster. Input rasters should use the same coordinate system, cell size, extent, and grid alignment.
Use Cases
- Count how often multi-temporal raster values exceed a threshold.
- Identify cells that repeatedly meet a condition, such as temperature above a limit or NDVI below a target value.
- Use the result as an intermediate raster in a longer iXGIS analysis workflow.
Parameters
| Parameter | Description | Notes |
|---|---|---|
| Input raster file | Raster files for frequency calculation. | Required. |
| Comparison condition | Comparison operator used between each raster cell value and the constant value. | Required. Default: greater. Options: greater than (greater), greater than or equal to (greater_equal), less than (less), less than or equal to (less_equal), equal to (equal), not equal to (not_equal). |
| Comparison constant value | Constant value used for the cell-by-cell comparison. | Required. Default: 0.0. |
| Invalid value handling strategy | Controls how NoData values affect the output. | Optional. Default: False. True: the result is NoData only when all values are NoData. False: the result is NoData if any value is NoData. |
| Output raster file | Output raster containing the frequency count. | Required. |
Steps
- Open the Geoprocessing Toolbox in iXGIS, go to Spatial Analysis Tools > Local Analysis, and start Raster Frequency Analysis by Constant.
- Select the input raster files and confirm that they can be read correctly.
- Set the comparison condition, comparison constant value, and invalid value handling strategy.
- Specify the output raster file and confirm the output path, format, and file name.
- Click Run. After the task completes, review the output value range and spatial pattern.
Notes
- For multi-raster calculations, verify that the coordinate system, cell size, extent, and grid alignment are consistent.
- Define how NoData participates in comparison and statistics before running the tool, then validate the output NoData encoding.