docs: add a platform comparison page

docs/comparison.md

@@ -0,0 +1,153 @@
+# GeoLibre vs. other GIS platforms
+
+How GeoLibre compares to the desktop GIS, cloud GIS, and web-mapping tools people
+most often ask about: **QGIS**, **ArcGIS Pro**, **ArcGIS Online**, **Felt**, and
+**kepler.gl**.
+
+GeoLibre is not trying to replace any of these outright. It occupies a spot none
+of them quite fills: a **free and open-source GIS that runs in a browser tab with
+nothing installed**, keeps your data on your own machine, and still ships real
+analysis, spatial SQL, cartography, and a project file — then packages the *same*
+app as a desktop install, an Android app, and a Jupyter widget.
+
+!!! note "How to read this"
+    Comparisons like this age quickly and are written by an interested party. The
+    GeoLibre column reflects [what ships today](features.md); the other columns
+    describe each product's mainstream, out-of-the-box behavior as of
+    **August 2026**, not what is reachable with every add-on, extension, or
+    third-party plugin. Where a capability arrives through a separate product
+    (QField for QGIS in the field, ArcGIS Field Maps for ArcGIS), the table says
+    so rather than crediting it to the base product. Found something wrong or
+    out of date? Please
+    [open an issue](https://github.com/opengeos/GeoLibre/issues) — corrections
+    are welcome.
+
+## At a glance
+
+| | **GeoLibre** | **QGIS** | **ArcGIS Pro** | **ArcGIS Online** | **Felt** | **kepler.gl** |
+|---|---|---|---|---|---|---|
+| **License** | MIT, open source | GPL-2.0+, open source | Proprietary | Proprietary | Proprietary | MIT, open source |
+| **Cost** | Free | Free | Paid subscription | Paid subscription (credit-metered analysis) | Paid subscription | Free |
+| **Browser** | Full app, nothing to install | No official browser build | No | Yes (the product *is* the browser app) | Yes (browser-only) | Yes |
+| **Desktop** | Windows, macOS, Linux (Tauri) | Windows, macOS, Linux | Windows only | — | — | — |
+| **Mobile** | Native Android app; responsive touch layout | Via QField / Mergin Maps (separate apps) | — | Via ArcGIS Field Maps (separate app) | Responsive web | Responsive web |
+| **In Jupyter** | Full app as an anywidget, two-way sync | Via `qgis` bindings, not the UI | Notebooks drive `arcpy`, not the UI | ArcGIS API for Python | — | Yes (widget) |
+| **Works offline** | Yes — PWA install, offline area download, desktop build | Yes | Yes | Limited (Field Maps offline areas) | No | Client-side, but assets are hosted |
+| **Where your data lives** | Your device — processed client-side in the browser session | Your device | Your device / your enterprise geodatabase | Vendor cloud | Vendor cloud | Your browser |
+| **Project file** | `.geolibre.json` (open, documented) | `.qgs` / `.qgz` (open) | `.aprx` (proprietary) | Web map JSON (hosted) | Hosted map (no local file) | Exportable map config JSON |
+
+## Data and formats
+
+| | **GeoLibre** | **QGIS** | **ArcGIS Pro** | **ArcGIS Online** | **Felt** | **kepler.gl** |
+|---|---|---|---|---|---|---|
+| **Format breadth** | Wide — DuckDB-WASM Spatial plus in-house readers | **Widest** — everything GDAL/OGR reads | Very wide, plus native Esri formats | Common upload formats | Common upload formats | CSV, GeoJSON, Arrow/Parquet |
+| **Cloud-native vector** | GeoParquet, FlatGeobuf, PMTiles, streamed over HTTP range requests | GeoParquet, FlatGeobuf, PMTiles (recent GDAL) | GeoParquet (recent), no native PMTiles | — | Some cloud sources on higher plans | Arrow/Parquet |
+| **Cloud-native raster** | COG, Zarr, Cloud-Optimized NetCDF/HDF, kerchunk, MBTiles | COG, Zarr (plugin-assisted) | COG; Zarr via extensions | Hosted imagery layers | GeoTIFF upload | — |
+| **STAC** | Built-in catalog browser + STAC Index discovery | Via plugins | Via add-ins | Living Atlas (not STAC) | — | — |
+| **OGC services** | XYZ, WMS, WFS, WMTS, OGC API Features/Tiles, with GetCapabilities discovery | Full OGC support | Full OGC support | Yes | Limited | XYZ / vector tiles |
+| **Esri services** | ArcGIS FeatureServer, VectorTileServer, I3S, `.gdb` folders (desktop) | Yes | Native | Native | Some ArcGIS layers | — |
+| **Databases** | PostGIS browsing, DuckDB, in-browser PGlite/PostGIS | PostGIS, SpatiaLite, Oracle, SQL Server, SAP HANA | Enterprise geodatabases (SDE) | Hosted only | PostGIS / Snowflake connections (higher plans) | — |
+| **3D and point clouds** | LiDAR, 3D Tiles, I3S, Gaussian splats, glTF/GLB, Cesium globe pane | Point clouds, 3D map view, tiled scene layers | **Deepest 3D** — scenes, I3S, mesh, LAS | Scene Viewer | — | Extrusions and hexbins only |
+| **Planetary basemaps** | Moon, Mars, Mercury, Venus, Galilean moons, Titan, Pluto, Charon — with a per-project ellipsoid driving measurements | Via plugins | Limited | — | — | — |
+
+## Analysis and processing
+
+| | **GeoLibre** | **QGIS** | **ArcGIS Pro** | **ArcGIS Online** | **Felt** | **kepler.gl** |
+|---|---|---|---|---|---|---|
+| **Geoprocessing tools** | **1,000+** (Whitebox suite + GeoLibre's own), running in the browser on WebAssembly | **1,000+** (native, GDAL, GRASS, SAGA) | **Most mature and complete**, plus paid extensions | A useful subset, credit-metered | A small set of common tools | None (filter and aggregate only) |
+| **Where analysis runs** | Your browser (WASM), no server required; optional Python sidecar on desktop | Your machine | Your machine, or a server/portal | Vendor cloud | Vendor cloud | Your browser |
+| **Vector analysis** | Buffer, overlay, dissolve, joins, selection, topology checks — Turf.js, or GeoPandas via Pyodide/sidecar | Comprehensive | Comprehensive | Common tools | Common tools | — |
+| **Raster analysis** | Hillshade, slope, contour, zonal/focal stats, raster calculator, reclassify, mosaic — rasterio sidecar with a browser fallback | Comprehensive (GDAL/GRASS/SAGA) | Comprehensive; Spatial Analyst extension | Limited | — | — |
+| **Spatial SQL** | DuckDB Spatial, PGlite/PostGIS, and Apache Sedona — **all in the browser** | Virtual layers, DB Manager, PostGIS connections | SQL against enterprise geodatabases | — | SQL on connected sources (higher plans) | — |
+| **Model / batch chaining** | Batch runner with model and pipeline chaining | Graphical Model Designer | ModelBuilder | — | — | — |
+| **Spatial statistics** | Toolbox including Emerging Hot Spot Analysis | Via plugins and processing providers | Full Spatial Statistics toolbox | Some | — | — |
+| **Network analysis** | Isochrones, service areas, OD cost matrices, routing | QGIS Network Analysis, plugins (ORS, pgRouting) | Network Analyst extension | Routing services (credits) | — | — |
+| **AI / ML** | AI Segmentation (SamGeo/SAM 3), in-browser ONNX/YOLO object detection | Via plugins | `arcgis.learn` deep-learning toolset | Pretrained models (credits) | — | — |
+| **Processing history** | Every run listed, re-runnable, with copyable Python | History panel | Geoprocessing history | — | — | — |
+
+## Cartography, styling, and layout
+
+| | **GeoLibre** | **QGIS** | **ArcGIS Pro** | **ArcGIS Online** | **Felt** | **kepler.gl** |
+|---|---|---|---|---|---|---|
+| **Renderers** | Single, categorized, graduated, rule-based, expression, heatmap, cluster, proportional symbols, diagrams | **Richest** — plus every symbol layer type | Very rich | Smart-mapping styles | Simple, well-designed defaults | Visualization-oriented |
+| **Data-defined everything** | Expression Builder wired into filters, labels, styling, field calculation, selection | Yes, pervasive | Attribute-driven symbology (Arcade) | Arcade | — | — |
+| **Labeling** | Data-defined engine with placement, offset, rotation, wrap, dedup | Best-in-class placement engine | Maplex label engine | Basic | Basic | Basic |
+| **Print layout** | Print Layout composer with legend, scale, title block, atlas / map series, PNG and PDF | Full print composer with atlas | Full layout view with map series | Basic print / export | Export to image and PDF | Image export |
+| **Style interchange** | Imports and exports **OGC SLD, QGIS QML, and Mapbox GL JSON** | QML, SLD | `.lyrx`, limited SLD | — | — | — |
+| **Project import** | Reads **QGIS `.qgs`/`.qgz` and ArcGIS Pro `.aprx`/`.mapx`** | Reads its own | Reads its own (and `.mxd`) | — | — | — |
+| **Story maps** | Built-in story map builder with presenter view and standalone HTML export | Via plugins | — | ArcGIS StoryMaps (separate product) | Shareable maps, not chaptered stories | — |
+| **Dashboards** | Dashboard panel of chart and indicator widgets with cross-filtering | Via plugins | — | ArcGIS Dashboards (separate product) | — | Charts and filters in-map |
+
+## Automation, extensibility, and sharing
+
+| | **GeoLibre** | **QGIS** | **ArcGIS Pro** | **ArcGIS Online** | **Felt** | **kepler.gl** |
+|---|---|---|---|---|---|---|
+| **Scripting** | Python Console, `geolibre` Python package, docked Jupyter notebook beside the map | PyQGIS, `qgis_process` headless CLI | `arcpy`, notebooks | ArcGIS API for Python / JavaScript | REST API + Python client | JS library |
+| **Notebook integration** | The **whole app** embeds as a Jupyter anywidget with two-way project sync | Bindings, not the UI | Notebooks in Pro drive `arcpy` | Hosted notebooks | — | Widget |
+| **Plugin ecosystem** | TypeScript plugin API, built-ins, zip installs, bundled drop-ins | **Largest** — thousands of Python plugins | .NET add-ins, Python toolboxes | Configurable app templates | None (API only) | Fork the library |
+| **AI assistant** | Natural-language assistant that turns plain English into auditable, undoable operations; bring your own API key | Via plugins | Copilot features | — | AI-assisted map making | — |
+| **Real-time collaboration** | Yes (MVP, self-hosted server) + anchored review comments | No (Mergin Maps for sync) | No | Shared editing of hosted layers | **Best-in-class** multiplayer editing and comments | — |
+| **Embedding** | `maponly` and `layout=viewer` URL modes, a versioned `postMessage` API, and the typed `@geolibre/embed` npm client | QGIS Server / QGIS2Web export | — | Embeddable web apps | Embeddable maps | Embeddable |
+| **Self-hosting** | Docker image, or serve the static build anywhere | QGIS Server | ArcGIS Enterprise (paid) | — | — | Static build |
+| **Standalone export** | Whole project to **one offline HTML file**, no server | Via qgis2web plugin | — | — | — | HTML export |
+
+## Where each one is the right choice
+
+**Choose GeoLibre when** you want a real GIS in a browser tab with nothing to
+install, your data has to stay on your machine, you work with cloud-native
+formats (COG, GeoParquet, PMTiles, Zarr, STAC), you want the same app on desktop,
+Android, and inside a notebook, or you are embedding a map workspace into your
+own product and want an open, documented project format and license.
+
+**Choose QGIS when** you need the widest possible format support through
+GDAL/OGR, the deepest desktop cartography and label placement, a mature plugin
+for a niche task, or heavy local processing over datasets larger than a browser
+can hold.
+
+**Choose ArcGIS Pro when** you are already in the Esri ecosystem, need
+enterprise geodatabase editing and versioning, the deepest 3D and imagery
+workflows, or a specific specialized toolbox with organizational support behind
+it.
+
+**Choose ArcGIS Online when** the priority is hosted layers, organizational
+sharing and permissions, and the surrounding Esri app family (Dashboards,
+StoryMaps, Field Maps, Experience Builder).
+
+**Choose Felt when** collaborative, low-friction map *making* with a team is the
+whole job, and polished multiplayer editing matters more than analysis depth or
+keeping data off a vendor's servers.
+
+**Choose kepler.gl when** you want fast, beautiful exploratory visualization of
+large point and trip datasets and do not need analysis, a project format, or
+layer management.
+
+They also compose. GeoLibre reads QGIS and ArcGIS Pro projects and exchanges
+symbology as SLD, QML, and Mapbox GL JSON, so it is reasonable to author in
+QGIS or Pro and publish or embed with GeoLibre.
+
+## Where GeoLibre is not the strongest option
+
+Stated plainly, so the table above is worth trusting:
+
+- **Very large local datasets.** Browser memory and WASM are real limits.
+  Client-side vector tiling and streaming push the ceiling up, but a
+  multi-gigabyte local processing job still belongs on a desktop GIS. The
+  desktop build's Python sidecar helps; QGIS or ArcGIS Pro helps more.
+- **Format breadth.** GDAL/OGR reads more than DuckDB-WASM Spatial does. Some
+  formats — notably File Geodatabase — only work in the desktop build.
+- **Depth of specialized toolboxes.** ArcGIS Pro's Spatial Analyst, Geostatistical
+  Analyst, and Network Analyst, and QGIS's twenty years of plugins, cover
+  workflows GeoLibre has no equivalent for.
+- **Enterprise data management.** Versioned editing, replication, and enterprise
+  geodatabase administration are outside GeoLibre's scope.
+- **Maturity.** GeoLibre is stable and in active development, but it is far
+  younger than QGIS or ArcGIS. Some capabilities listed as shipping are recent —
+  see [Recently added](index.md#recently-added).
+
+## See also
+
+- [Features](features.md) — the complete, current inventory of what GeoLibre does
+- [Roadmap](roadmap.md) — release history and what is planned next
+- [Getting Started](getting-started.md) — install the app or open GeoLibre Web
+- [Importing a QGIS project](user-guide/projects.md#importing-a-qgis-project) and
+  [an ArcGIS Pro project](user-guide/projects.md#importing-an-arcgis-pro-project)

docs/features.md

@@ -4,7 +4,8 @@ A feature-by-feature list of what GeoLibre can do today — the latest release p
 what has landed on `main` since (see [Recently added](index.md#recently-added)).
 For task-oriented walkthroughs, see the [User Guide](user-guide/interface.md) and
 the [Tutorials](tutorials/index.md); for what is planned next, see the
-[Roadmap](roadmap.md).
+[Roadmap](roadmap.md). For how this stacks up against QGIS, ArcGIS, Felt, and
+kepler.gl, see the [Comparison](comparison.md).
 
 ## Platforms and interface
 

docs/index.md

@@ -167,8 +167,9 @@ Other parameters control the toolbar, panels, and theme. See [Embedding & Sharin
 
 GeoLibre is **stable and in active development**, with regular releases on
 [GitHub](https://github.com/opengeos/GeoLibre/releases). For the complete,
-current inventory see [Features](features.md); for the full release history and
-what comes next, see the [Roadmap](roadmap.md).
+current inventory see [Features](features.md); for how GeoLibre compares to
+QGIS, ArcGIS, Felt, and kepler.gl, see the [Comparison](comparison.md); for the
+full release history and what comes next, see the [Roadmap](roadmap.md).
 
 ### What ships today
 

mkdocs.yml

@@ -41,6 +41,7 @@ nav:
   - Home: index.md
   - Getting Started: getting-started.md
   - Features: features.md
+  - Comparison: comparison.md
   - Demos: demos.md
   - Downloads: downloads.md
   - Launch GeoLibre Web: /demo/