Tutorial: Create a field data collection app for groundwater studies
|Site:||IHE DELFT OPEN COURSEWARE|
|Course:||GIS training for Hydrogeological Applications|
|Book:||Tutorial: Create a field data collection app for groundwater studies|
|Printed by:||Guest user|
|Date:||Friday, 27 May 2022, 2:27 PM|
Table of contents
In the previous topic we have learned how to use data that is available on the internet.
Often, however, you have to collect your own data, because it's not available or too coarse in the online sources. Nowadays you would use an app for that.
After this tutorial you'll be able to:
- use QGIS to setup a surveying project
- configure map themes with online and offline layers
- design the field form
- synchronise the QGIS project with the Mergin cloud service
- synchronise the Input app on the mobile phone with the Mergin cloud service
- use the Input app for surveying
- synchronise the data collected in the field with the Mergin cloud service and the QGIS project
Input is a simple survey app
allowing users to capture data in field.
Forms and data preparation can be done in QGIS software and synchronised
with the Input app using the Mergin plugin and repository.
Input is not aimed to be a full GIS/mapping application. It is designed with simplicity, ease of use and seamless data synchronisation in mind.
A typical workflow for using Input consists of the following steps:
Preparing project: user loads background and survey layers, set up the forms, apply styling to the layers, set up map themes and define the layers to be used for survey purpose.
Data/project transfer: once the project set up, users need to transfer data to the device. This can be achieved through Mergin.
Working with Input: map navigation, data editing, including filling the forms, viewing existing data and uploading the changes back to Mergin.
2. Project preparation
We will start with preparing the project in QGIS.
In the project we have to distinguish:
- Background layers that provide context in the field
We can use both offline and online layers and they can be raster or vector.
Our project will have the following background layers:
- Google satellite online
- Google satellite offline
- OpenStreetMap online
- OpenStreetMap offline
- Vector layer with boundary of the study area
2.1. Adding the study area boundary
First we're going to define the study area boundary and add that polygon to the project, so we also know where the border is when we're navigating with the app in the field.
1. Start QGIS with a blank project
2. Change the projection of the project to UTM Zone 36S/WGS-84 by clicking on the EPSG code in the lower right corner .
3. In the dialogue filter on the EPSG code 32736, select the projection and click OK.
Because this isn't a survey layer, we need to make this vector layer read-only. The Input app interpretes read-only layers as non-survey layers.
28. In the Main Menu select Project | Properties...
29. Select the Data Sources tab.
30. Check the box for Read-only for the Boundary layer.
2.2. Add online layers and make available offline
If you have internet connectivity in the field, you can use a WM(T)S or online XYZ tiles as your background map. In the previous section we've already added the OSM Standard layer. In this section we'll also add Google Satellite to our survey project. We'll also make the online layers offline available just in case we don't have internet connectivity in the field.
Let's first add Google Satellite to the project.
1. In the main menu go to Web | QuickMapServices | Google | Google Satellite.