Field data collection is where GIS meets the real world: a surveyor with a phone, a forester marking trees, a utility crew logging assets. The app you choose decides whether that data comes back clean and ready to use, or as a spreadsheet that needs hours of repair. Three apps lead the field in 2026, and they map neatly onto the three main GIS ecosystems.

QField is the mobile companion to QGIS, and it is free and open source. You prepare a QGIS project on the desktop, package it with the QFieldSync plugin, and open it on an Android or iOS device. Forms, photos, GPS positions and offline basemaps all work without a connection, and the data syncs back into the same QGIS project. It is the best choice if your team already works in QGIS, and its only real cost is the time spent setting up the project properly.

Mergin Maps is built on the same QGIS foundation but adds cloud synchronisation and team collaboration. Field workers sync their edits to the cloud, and the office sees them in QGIS within minutes. There is a free tier for small projects and paid plans for larger teams, and it handles the version conflicts that appear when several people edit the same dataset. It is the best choice for distributed teams that need everyone working on the same live data.

ArcGIS Field Maps is Esri's offering, and it is the strongest choice if your organisation already runs ArcGIS. It combines data collection, viewing and navigation in one app, works offline, and integrates with ArcGIS Online and Enterprise. The cost is the ArcGIS licence, which is substantial, but for an Esri shop the integration is worth it. It also has the most polished interface of the three, which matters when field staff are not GIS specialists.

Whichever app you choose, the setup rules are the same. Design the form before you go out, with dropdown lists instead of free text wherever possible, because a typo in a free-text field is a data error. Test the project offline, because field connectivity is never as good as you expect. Set the GPS accuracy threshold so the app warns you when the fix is poor, and take a photo of every feature that might be disputed later. The app is only as good as the project behind it.