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Introduction

Conness GIS is an open-source, code-driven framework for building widget-based GIS web apps on MapLibre GL JS. It's a clone-and-edit alternative to proprietary GIS app builders: instead of dragging boxes around a builder UI, you describe your app in a handful of configuration files and the framework assembles the rest.

What you get

Out of the box, a cloned project gives you a complete mapping application:

  • Declarative layers — point, line, and polygon data from GeoJSON, PMTiles, FlatGeobuf, GeoParquet, and ArcGIS REST services, all configured as plain objects.
  • A widget system — a layer list, legend, basemap switcher, search, measure, draw, bookmarks, and live coordinates — placed wherever you want them (top bar, left rail, or floating over the map).
  • Feature popups — opt-in per layer, rendered by templates you control.
  • A mobile layout — the same app reflows into a bottom-sheet UI on small screens, automatically.
  • One-palette theming — change a single color token and the whole app re-skins.
  • A responsive shell — top bar, collapsible side panels, floating controls, a right-click context menu, and a boot-time loading overlay.

The core idea

The project is split into two halves:

  • The shell (app/src/) is framework code. You rarely touch it — eventually it becomes a published package.
  • The user surface (the files at the root of app/) is yours: settings.ts, layers.ts, symbology.ts, popups.tsx, info.md, and the widgets/ folder.

You build your app entirely in the user surface. The shell reads it and renders. This boundary is what makes Conness GIS a template rather than a one-off app — see Concepts for how it fits together.

Built with

Conness GIS stands on a lot of excellent open-source work. Thank you to every project below:

Core

Mapping & geospatial

UI & content

Ready to run it? Head to the Quick Start.