FAQ¶
How is this different from QGIS's built-in Zonal Statistics?¶
QGIS's native Zonal statistics processes a single raster band at a time and writes into the vector layer. Multiband Zonal Stats is built for multiband rasters: it aggregates every selected band in one tiled pass and writes a tidy CSV, with dedicated categorical support (majority/minority/variety and per-class breakdowns) that the native tool does not provide.
The tool says it needs a "file-based raster". Why?¶
The engine reads the raster directly with GDAL for speed, so it needs a file-backed source (GeoTIFF, IMG, VRT, …). For WMS/tiled/provider-only layers, export to GeoTIFF first and run the analysis on the export.
My sums look like text in Excel (with a leading apostrophe).¶
That's a locale mismatch, not a bug: the CSV uses a . decimal separator but your Excel expects a ,. Import via Data → From Text/CSV and set the decimal separator, or reduce the output to a few decimal places for cleaner numbers.
I got "more than 65,536 distinct values".¶
You ran Categorical mode on a raster that looks continuous. Switch to the Continuous tab, or reclassify the raster into discrete classes first.
How do I exclude out-of-boundary or fill pixels?¶
Put the value(s) into Exclude values (e.g. 0, or 0, 255). They're dropped from the calculation like nodata, across all bands. The Histogram preview helps you spot which value dominates.
Can it handle overlapping polygons and multipart features?¶
Yes. Shared pixels are counted for every overlapping zone (overlaps are rasterized in separate passes), and all parts of a multipart feature share one zone ID, with holes respected.
Does it work with geographic (lat/long) rasters?¶
Yes — statistics and class counts work regardless of CRS. (There is no metric-area output; pixel counts are always available.)
Is my polygon_id unique per row?¶
Not necessarily — it repeats across bands, and across classes in the breakdown layout. Use the fid column (the first column) as the unique per-row key.
Which QGIS versions are supported?¶
QGIS 3.34 or newer, from a single code path that runs on QGIS 3.34 through 4.x (Qt5 and Qt6).
Where do I report a bug or request a feature?¶
On the GitHub issue tracker.