# Using Mergin Maps Mobile App
WARNING
Our mobile app was redesigned. We are in the process of updating this content to reflect these changes.
In the last tutorial we created a new Mergin Maps project in QGIS with layers for surveying trees and hedges. You'll now learn how to:
- Open the QGIS project in Mergin Maps mobile app
- Set GPS accuracy thresholds
- Switch between layers to capture new point and linear features
- Sync and save your data in Mergin Maps cloud
TIP
Need help navigating Mergin Maps mobile app? Mergin Maps mobile app Interface contains the overview of the functionality of the app's buttons and features.
# Opening the project on your mobile device
Open Mergin Maps mobile app on your mobile device
Open the My projects tab of the Projects page
Download the trees-and-hedges project:
The project should now be downloaded to the device:
Switch to the Home tab and tap the trees-and-hedges project
The project should now be shown:
Pinch the screen to zoom in on your location. If you lose sight of your location, use the GPS button to recentre the map on your position.
# GPS accuracy
Current GPS accuracy affects the quality of field data that you capture in the field.
Let's see what can happen when capturing field data. Press the Record button:
You may now see a warning about GPS accuracy:
What does it mean? When GPS accuracy falls below a threshold, Mergin Maps mobile app reports this to the user using this warning. This threshold can be changed and it is highly recommended to set it to a sensible value as described below.
The mobile app uses a traffic light system to display GPS status:
- Green: OK - GPS accuracy within defined threshold
- Orange: Warning - GPS accuracy outside of defined threshold
- Red: No GPS - there's no GPS signal or the GPS is unavailable
The current value of GPS accuracy, traffic light dot and accuracy bubble is displayed here:
# How to change the GPS accuracy threshold
Cancel recording and open Settings:
Set Accuracy threshold to a sensible value
Typical values could range between 2m and 25m and typically depend on the accuracy of your mobile device and your use case. Higher accuracy can be achieved by using external GPS antenna.
Watch the traffic light change colour as you change the accuracy threshold.
# The active layer
In a moment we'll survey a tree. Surveyed features are added to the active layer. The project contains three different layers so we'll now ensure the trees layer is set as the active layer.
Press the Record button:
The active layer is shown just above the button bar:
Tap the active layer and set it to trees:
Press the Add Point button to survey a new tree.
Notice how the form (e.g. species drop-down list) reflects how we configured the project in QGIS:
Enter some values and Save the new point
# Editing features and the preview panel
Tapping a map feature shows its preview panel.
Tap the tree you just surveyed:
Information shown in the preview panel can be customised. We'll learn how in the next tutorial.
Experiment with editing the tree's species and location using the edit button:
The edit button can be used to edit the feature's attributes (e.g. species, condition) and even its location/geometry.
# Survey linear features
When creating the project in QGIS, we included a layer for linear features called hedges. We'll now learn how to survey lines in the mobile app.
TIP
Areas can be captured in a similar way to lines if the project has editable area/polygon layers.
Set hedges as the active layer.
Refer back to the active layer section if you cannot remember how to do this.
We'll now survey a hedge feature.
Use tools in the bottom panel to survey the line: use Add Point to add points along the line and tab Done when finished
TIP
Drag the map to position points manually or press GPS to recentre the map on your location.
- Enter some attributes and a photo for the hedge:
When I surveyed my hedge, it was quite difficult to distinguish from the background map - it was a thin, light green line:
We will learn how to change layer styles in the next tutorial.
# Saving data to the cloud
To conclude this tutorial we will push the data we just collected back to Mergin Maps.
- Open the Home tab of the Projects page
- Press the sync button:
When the sync process has completed your data has been stored safely in the cloud.