QField field data collection: from QGIS project to synced survey

How field data collection with QField works

QField is the open source mobile app of the QGIS ecosystem. It opens an ordinary QGIS project on the phone, with its symbology, layers and forms, and lets you add or edit features. It runs on Android and iOS, as well as Windows, macOS and Linux.

For a team to work on the same project, you need a sync service between the office and the devices. That is the role of QFieldCloud, and of LizPack Field, which relies on the same sync technology and works with the official QField app. LizPack is an open source geospatial infrastructure: it replaces neither QGIS nor QField, it hosts and maintains the sync service and connects it to your PostGIS databases. For more on how it works, see what LizPack does.

1. Prepare the collection project in QGIS.
2. Publish it to the sync service.
3. Collect with QField, online or offline.
4. Sync and find the data in QGIS or PostGIS.

Prepare the collection project in QGIS

A campaign succeeds or fails at the office. A well-prepared project avoids free-text entries, duplicates and misplaced features.

• One layer per survey type. Points for assets, lines for networks, polygons for parcels. Each layer carries only the fields you need.
• Constrained forms. In the layer properties, the form tab lets you set value lists, checkboxes, dates, photos, default values and constraints. A closed list beats a text field.
• Automatic values. Entry date, surveyor name or identifier can be filled by an expression, which removes a source of errors.
• A light basemap. For offline work, plan an embedded basemap limited to the work area rather than an online service.
• Symbology readable in sunlight. Strong colors, short labels, visibility scales suited to a small screen.

If the data must land in a PostGIS database, create the collection layers directly in that database, with an auto-increment primary key. The guide sync QField with PostGIS and Lizmap covers this case.

Example: the form for a water point inventory

To make these principles concrete, take a common campaign: an inventory of water points in an area (wells, boreholes, standpipes). The layer is a point layer, and each field gets a suitable input widget in QGIS.

Three choices make the difference. Closed lists guarantee usable values with no cleanup. Constraints, such as a required condition or a bounded flow, prevent saving an incomplete or absurd record. Default values computed by an expression (date, surveyor) remove repetitive entries that surveyors always end up rushing.

Also think about field order: the surveyor fills in the form from top to bottom, standing, sometimes in bright sun. Put first what can be seen immediately (type, condition), then what requires a measurement, and the free remark at the end. If the form gets long, group the fields into tabs in the layer's form configuration.

Send the project to the phones

The project is sent from QGIS to LizPack Field. It then becomes available to invited collaborators, whom you manage per project with roles from the dashboard, in English, French, Spanish or Portuguese.

On the phone, each surveyor installs the official QField app from their device's store, signs in with their account and downloads the project. From then on, the project is stored on the device: layers, forms and the basemap prepared for offline use.

• Have the project downloaded at the office, on a reliable network, before leaving.
• Run a full test with one surveyor: open, capture a feature, take a photo, sync.
• Check the battery and free storage of each device, especially if the basemap is large.

Finally, plan a short training session for surveyors, even if they already know how to use a phone. Half an hour is usually enough: open the project, find your location, create a feature, fill in the form, take a photo, fix a mistake and sync. Run it with the campaign's real project, not a demo: surveyors then discover the lists and constraints they will meet in the field.

Choosing devices for data collection

QField runs on ordinary Android and iOS phones and tablets. You do not need to buy specialized hardware to get started, but a few criteria prevent painful days.

• The screen. A bright screen stays readable in full sun; a tablet is more comfortable for drawing polygons, a phone slips into a pocket more easily.
• Storage. The project, its embedded basemap and the photos pile up on the device. Keep a comfortable margin of free space, especially for long campaigns without syncing.
• Battery life. GPS and an always-on screen drain a battery fast. A power bank and a cable are part of the basic kit.
• Protection. A rugged case and rain protection cost little compared with a lost device holding unsynced data.
• Accuracy. A phone's built-in GPS gives accuracy of a few meters, enough for an asset inventory. For finer surveys, such as parcel boundaries, QField can use an external GNSS receiver; check the model's compatibility in the QField documentation.

One last tip: standardize hardware when you can. A team with identical devices learns faster, and problems one surveyor runs into are fixed the same way for everyone.

Collect without a network

Once the project is downloaded, QField needs no connection to display the map and record data. Changes are kept locally on the device, then sent as soon as a connection is available. GPS positioning does not depend on the mobile network.

• Capture as close to the feature as possible and wait for the displayed accuracy to be acceptable before saving a point.
• Take photos from the form so they stay attached to the right feature.
• Do not uninstall the app or delete the project before syncing: unsent data exists only on the device.
• On a long mission without network, sync every time you pass through a covered area rather than at the end of the week.

Positioning deserves particular attention. At the first start of the day, GPS can take several minutes to get a fix: leave the phone under open sky before you begin. Under trees, between buildings or inside a building, accuracy drops sharply. When a point cannot be captured properly, it is better to place it by hand on the basemap and flag it in the remark field than to save a wrong position without saying so.

Sync and use the collected data

Back in coverage, the surveyor starts the sync from QField. Changes go up to LizPack Field, where the dashboard shows projects, files, the job log and the changes received.

Pro plan: 15 USD per month at the time of writing. Current quotas and prices are on the pricing page.

With a PostGIS database hosted by LizPack, the data is immediately visible in QGIS Desktop, and in a Lizmap map that displays those layers, updated at each sync. To share the result with a simple link, see create a map online and share it.

At the end of a campaign, get into the habit of archiving: a copy of the data in GeoPackage format, the project version used, the dates, the list of surveyors and the incidents noted. This small folder lets you compare one campaign with the next, back up the figures for a funder and rerun an identical collection a year later without rebuilding everything.

Organize the team and the QField field data collection day

A good project is not enough: successful QField field data collection also depends on clear team organization. Campaigns that go wrong often share the same cause: nobody knows who surveyed what, or which devices have synced.

• One project lead. They prepare the project in QGIS, invite collaborators, follow the changes received in the dashboard and settle any doubt about an entry.
• Assigned sectors. Split the study area into sectors and give one to each surveyor. A sector layer in the project, visible on the phone, prevents two surveyors from covering the same street.
• Suitable roles. A surveyor who only collects does not need the same rights as the person who edits the project. Roles are set per project from the dashboard.
• A surveyor ID in every record. A field filled automatically with the user's name lets you track each person's contribution and get back to the right person if there is a question.

For the day itself, a simple routine prevents most losses. In the morning, each surveyor checks that the project is up to date on their device and that the battery is full; a power bank helps on a long round, since GPS and an always-on screen use a lot of power. During the round, they save each feature before moving to the next one and never leave a form open. In the evening, or as soon as they get a network, they sync, and the lead checks the received data at the office: number of features, photos present, required fields filled in.

This daily check is the best guarantee of quality. An error spotted the same evening is fixed on site the next day; spotted three weeks later, it often requires another trip. With the Pro plan and a PostGIS database, this check can be done with a simple query or in QGIS as soon as the sync is complete.

Checklist before heading into the field

Before each QField field data collection campaign, this list takes a few minutes at the office. It covers the points that, in practice, waste the most time when forgotten.

1. The project opens without errors in QGIS and every layer displays.
2. The forms have been tested: lists, constraints, default values and photo all work.
3. The project is published to LizPack Field and each surveyor is listed as a collaborator with the right role.
4. Each device has downloaded the latest version of the project, on a reliable network.
5. A test record has been captured and synced, it shows up at the office, and it has then been deleted.
6. Batteries are charged, power banks too, and there is enough free storage.
7. Each surveyor knows their sector and the sync instructions.
8. The lead knows how to reach each surveyor during the day.

Keep this list in the project folder and add the incidents you encounter after each campaign: that is what helps the team improve from one campaign to the next.

Common mistakes to avoid

• Layers in an unsuitable format. A poorly managed shapefile or absolute paths to data on your computer prevent the project from being sent correctly. Prefer GeoPackage or PostGIS and relative paths.
• A basemap that is too heavy. It slows the download and fills the devices. Clip it to the study area.
• Forms that are too open. Every free-text field produces different spellings to clean up later.
• A campaign launched without a test. Ten minutes of testing at the office save a lost day in the field.
• Picking the tool before the need. If you are still torn between QField and a form tool, read QField or a form tool and QField or ArcGIS Field Maps.

Frequently asked questions