Skip to content

Adding Inputs

The Inputs tab is where you configure the raster data and basic settings for your analysis.

Raster Input Table

The input table displays all rasters that will be analyzed:

Column Description
Raster Path to the raster file
Year The year this raster represents (editable)

Adding Rasters

You have two options for adding rasters:

Click Add Files to open a file browser:

  1. Navigate to your raster files
  2. Select files (.tif, .tiff, or .img formats supported)
  3. Use ++ctrl+click++ to select multiple files
  4. Click Open

Supported Formats

The plugin supports GeoTIFF (.tif, .tiff) and ERDAS Imagine (.img) formats. All rasters must contain integer categorical data.

Click Add From Project to select from loaded layers:

  1. A dialog lists all raster layers in your current QGIS project
  2. Check the layers you want to include
  3. Click OK

Load First

Make sure your rasters are loaded in QGIS before using this option.

Automatic Year Detection

The plugin automatically extracts years from filenames:

  • Looks for 4-digit patterns: 19XX or 20XX
  • Examples:
    • landcover_2010.tif → Year: 2010
    • LULC_2015_classified.tif → Year: 2015
    • study_area_2020.img → Year: 2020

Manual Verification

Always verify the automatically detected years. Click on the Year cell to edit if needed.

Managing Rasters

Reorder rasters: Drag and drop rows to change the order. Rasters are processed in chronological order by year.

Remove rasters: Select a row and press Del or click the Remove button.

Minimum Requirement

At least one raster is required, but meaningful change analysis needs two or more rasters from different years.

Area of Interest (AOI)

Optionally limit your analysis to a specific geographic area:

  1. Load a polygon layer into QGIS
  2. Select it from the AOI Layer dropdown
  3. Only pixels within the AOI polygon(s) will be analyzed

AOI Benefits

  • Focus analysis on your study area
  • Exclude irrelevant regions
  • Reduce processing time for large rasters

AOI Requirements:

  • Must be a polygon or multipolygon layer
  • Should overlap with your raster extent
  • Can contain multiple features (all will be used)

NoData Handling

Configure how the plugin handles NoData (null/missing) values:

Use Raster NoData

Select Use raster NoData to use the NoData value defined in each raster's metadata:

  • Most GeoTIFFs have NoData values defined
  • Common values: -9999, 0, 255, etc.
  • The plugin reads this from GDAL metadata

Override NoData

Select Override to specify a custom NoData value:

  1. Enter the value in the text field
  2. This value will be treated as NoData in ALL input rasters

Override Carefully

When overriding, ensure the value you specify is not a valid class ID in any of your rasters.

Include NoData in Transitions

Check Include NoData class in transitions to treat NoData as a valid class:

  • Unchecked (default): NoData pixels are excluded from all calculations
  • Checked: Transitions to/from NoData are tracked in the transition matrix

This is useful when:

  • NoData represents a meaningful category (e.g., "No Data" or "Unclassified")
  • You want to track data coverage changes over time

Output Directory

Specify where analysis results will be saved:

  1. Click Browse
  2. Select or create a folder
  3. The path appears in the text field

Required

You must specify an output directory before running the analysis.

Output structure:

output_directory/
├── area_by_class.csv
├── net_gross_change_2010_2015.csv
├── net_gross_change_2015_2020.csv
├── transition_matrix_2010_2015.csv
├── transition_matrix_2015_2020.csv
├── transition_matrix_first_last_2010_2020.csv
├── top_transitions_2010_2015.csv
├── change_intensity.csv
├── change_frequency.tif
├── change_hotspot_2010_2015.tif
├── change_hotspot_2015_2020.tif
└── charts/
    ├── area_by_class.html
    ├── net_gross_change.html
    ├── transition_matrix_2010_2015.html
    └── ...

Input Requirements Summary

Requirement Details
Format GeoTIFF (.tif, .tiff) or ERDAS Imagine (.img)
Data type Integer (categorical). Float triggers a warning.
CRS All rasters must have the same CRS
Pixel size All rasters must have identical resolution
Extent All rasters should cover the same area
Grid alignment Pixel grids must align (same origin)
Minimum count At least 1 raster (2+ for change analysis)

Validation

Run validation to verify all requirements are met before analysis. See Validation for details.

Next Steps

After adding inputs:

  1. Configure the legend (optional but recommended)
  2. Set output options
  3. Validate your inputs