Tutorial: Create a field data collection app for groundwater studies
Conditions d’achèvement
2. Project preparation
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.
4. Install the QuickMapServices plugin: in the main menu go to Plugins | Manage and install plugins...
5. Install the QuickMapServices plugin.
6. In the main menu go to Web | QuickMapServices | Settings
7. In the QuickMapServices Settings dialogue click the More services tab.
8. Click Get contributed pack.
9. Click OK in the popup.
10. Click Save to close the QuickMapServices Settings dialogue.
11. In the main menu go to Web | QuickMapServices | OSM | OSM Standard.
Now
we need to find the location of our study area. Here we'll use an area
near Bangula within the Shire study area in Malawi of the previous
tutorials. But you can use the same methods for any other area.
12. Install the GeoCoding plugin.
13. Click the button to open the GeoCoding plugin.
14. Type Bangula in the Geocoding dialogue at Find address.
15. Click OK.
16. Choose Bangula, Nsanje, Southern Region, Malawi.
17. Click OK.
18. Zoom in to the area of interest. In our case we zoom in to an area with the city of Bangula and the pivot irrigation.
Now we're going to create a boundary polygon based on the extent of the area in the map canvas.
Note that if you need another area, you can replace the following steps by simply digitizing the boundary polygon.
19. Open the Processing Toolbox: in the main menu choose Processing | Toolbox.
20. In the Processing Toolbox choose Vector geometry | Create layer from extent.
21. In the Create layer from extent dialogue click and choose Use Canvas Extent.
The
boundary coordinates of the current map canvas are now filled in using
the projection of the project. Therefore it was important to set that at
the beginning of this tutorial.
22. Save the output Extent to a dedicated folder where we're going to save all the project data. In that folder save it to a GeoPackage with the name Bangula_study_area.gpkg.
23. Click Run. Click Close to close the dialogue after processing.
Now the wole rectangle polygon is filled with a random colour. Let's style the boundary.
24. Select the Bangula_study_area layer from the Layers panel and click to open the Layer Styling panel.
25. In the Layer Styling panel click on Simple fill. Then change the Symbol layer type to Outline: Simple line. Change the colour to red and make the Stroke width 0.66 mm.
Now the boundary polygon is ready.
26. Remove the GeoCoding Plugin Results layer from the Layers panel.
Save the project with the name Bangula_Groundwater_Survey to the Bangula_study_area.gpkg GeoPackage.
27. In the main menu choose Project | Save To | GeoPackage...
28. Connect to the Bangula_study_area.gpkg GeoPackage and type Bangula_Groundwater_Survey at Project.
29. 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.
30. In the Main Menu select Project | Properties...
31. Select the Data Sources tab.
32. Check the box for Read-only for the Boundary layer.
33. Click OK.
In the next section we'll add the Google Satellite layer and make OSM Standard and Google Satellite available offline too.