SamGIS QGIS Plugin - SAM2 Instance Segmentation on Your PC

This QGIS plugin brings Meta's Segment Anything Model 2 (SAM2) into QGIS, enabling instance segmentation directly on your PC and fully offline. No cloud APIs, no dedicated GPU — models run on-device via ONNX Runtime.

The plugin is part of the SamGIS ecosystem. While the web demo relies on a FastAPI backend using remote tile providers (e.g. OpenStreetMap), SamGIS for QGIS works entirely offline with any georeferenced image in a QGIS project.

Models are downloaded once from Hugging Face and stored locally in ~/.samgis/models/.

Screenshots

Select layers and prompts	Instance segmentation result

How it works

1. Install the QGIS plugin =) (the Python dependencies are handled under the hood by the plugin itself)
2. Load a georeferenced raster layer in QGIS
3. Create vector layers with point prompts (foreground/background) or rectangles (foreground only)
4. Select the raster layer and the vector layer(s) from the SamGIS modal dialog
5. If no SAM2 model is present, the plugin will prompt you to choose and download one (e.g. "SAM 2.1 Tiny uint8" ~32 MB for a quick start)
6. The pipeline then
   1. converts geographic (or projected, depending on the CRS) coordinates to pixel coordinates
   2. runs the actual inference using the selected model
   3. returns the segmentation mask converted to a polygon vector layer with CRS "EPSG:4326"

Key features

• Fully offline — models are downloaded once and stored locally
• 8 model variants — 4 sizes (Tiny, Small, Base+, Large) x 2 precisions (uint8, fp32)
• Point prompts — foreground (label=1) and background (label=0) points
• Rectangle prompts — bounding box via polygon vector layer
• Background inference — UI stays responsive during model execution
• Multi-band handling — supports grayscale, RGB, and multi-band rasters (1-3 bands)
• EPSG:4326 output — results are added as polygon vector layers
• Model management — download and selection via a dedicated settings dialog

Resources

• Source code and full documentation: trincadev/samgis-qgis-plugin
• Related: SamGIS web demo
• Requires QGIS 3.40+ LTR