GIS (Geographic Information System)

GIS (Geographic Information System) regroupe les systèmes, technologies et données pour capturer, stocker, manipuler, analyser, et visualiser des données spatiales géographiques. Composante critique de nombreuses industries : urbanisme, transport, livraison, telecom, agriculture précision, santé publique, défense, environnement, retail (site selection), marketing géographique.

Composants typiques :
(1) **Spatial database** — PostGIS, Oracle Spatial, SQL Server Spatial, MongoDB GeoJSON, Elasticsearch geo_point ; stockage et requêtes spatiales.
(2) **Map server / tile server** — GeoServer, MapServer, pg_tileserv, Tegola — serve map tiles vector ou raster.
(3) **Desktop GIS** — QGIS (open source leader), ArcGIS Pro (Esri, proprietary leader), MapInfo, GRASS GIS.
(4) **Web mapping libraries** — Leaflet (popular open source JS), Mapbox GL JS, OpenLayers, Cesium (3D), Google Maps JS API.
(5) **Routing engines** — OSRM, Valhalla, Graphhopper, pgRouting, Google Directions API.
(6) **Spatial analytics** — Carto, Mapbox Atlas, Tableau geo features, PowerBI.

Formats données :
- **Vector** : GeoJSON, KML, Shapefile (legacy ESRI), GeoPackage (modern SQLite-based).
- **Raster** : GeoTIFF, NetCDF (climate data), HDF.
- **Tiles** : MBTiles, PMTiles, Vector Tiles (Mapbox spec).
- **Streaming** : OGC API features.

Coordinate Reference Systems (CRS) / Projections :
- **EPSG:4326** — WGS84, lat/lon degrés (GPS standard).
- **EPSG:3857** — Web Mercator (Google Maps, OpenStreetMap rendering).
- **Local projections** — Lambert 93 France, etc.

Use cases business :
(1) **Logistics/delivery** — Uber, DoorDash, Amazon — routing, ETA, dispatch.
(2) **Real estate** — property search radius, school zones.
(3) **Retail site selection** — analyse footfall, demographics.
(4) **Telecom network planning** — coverage maps, optimal antenna placement.
(5) **Urban planning** — zoning, infrastructure.
(6) **Agriculture** — precision farming, satellite imagery.
(7) **Health** — epidemic spread tracking (COVID dashboards), accessibility analysis.
(8) **Insurance** — risk assessment (flood zones, earthquake fault lines).
(9) **Public sector** — election precincts, census, public transit.

OpenStreetMap (OSM) — free editable map of the world, foundation de nombreux services modernes (Mapbox builds on OSM, Apple Maps incorporated, etc.). Compétences DEA-C01, DP-300.