dash-openlayers

OpenLayers mapping components for Plotly Dash. Build maps declaratively in Python, use OpenLayers for rendering and editing, and receive map events and feature data in Dash callbacks.

Install

pip install dash-openlayers

Requires Python 3.10 or newer. Dash is installed as a package dependency.

Quick Example

import dash
from dash import Input, Output, html
import dash_openlayers as dol

app = dash.Dash(__name__)
app.layout = html.Div(
    [
        dol.Map(
            id="map",
            center=[10, 45],
            zoom=5,
            children=[
                dol.TileLayer(id="osm", source="OSM"),
                dol.VectorLayer(
                    id="places",
                    geojson={
                        "type": "FeatureCollection",
                        "features": [
                            {
                                "type": "Feature",
                                "geometry": {"type": "Point", "coordinates": [10, 45]},
                                "properties": {"name": "Sample place"},
                            }
                        ],
                    },
                ),
                dol.SelectInteraction(id="selection", layerId="places"),
                dol.LayerControl(id="layers"),
            ],
            style={"height": "600px"},
        ),
        html.Pre(id="selection-output"),
    ]
)


@app.callback(Output("selection-output", "children"), Input("selection", "selectedGeoJSON"))
def show_selection(selection):
    return str(selection or "Select a feature")


if __name__ == "__main__":
    app.run(debug=True)

Components

• Maps, synchronized view state, custom Proj4 projections, and click events.
• OSM/XYZ, GeoJSON vector, WMS, WMTS, MVT vector-tile, and WFS GeoJSON layers.
• Draw, select, modify, snapping, per-feature topology validation, and undo/redo.
• GeoJSON/WKT input and GeoJSON/WKT/TopoJSON edit output.
• Point clustering, decluttering, and layer visibility/opacity/order controls.

WFS-T writes are not performed by WFSLayer; see the guarded example in tests/demos/wfs_demo.py for an application-owned transaction callback.

Documentation

• Quickstart
• Usage guide
• API reference
• Architecture
• Testing

Contributing

See CONTRIBUTING.md for development setup and workflow.