Tutorial: Create a field data collection app for groundwater studies

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.

Now we can clearly see the pivots.

The next step is to make the OSM Standard and Google Satellite layers offline available for the study area. For that purpose we need to save the map canvas to MBTiles at a specified zoom level. First we're going to find the appropriate zoom level.

2. In the main menu choose View | Panels | Tile Scale.

The Tile Scale panel is now added.

3. Click on Google Satellite in the Layers panel and move the slider in the Tile Scale panel to the desired zoom level.

Note that the higher the level, the higher the resolution and the larger the file. Here we'll use zoom level 17.

4. Close the Tile Scale panel.

5. Click right on Bangula_study_area layer in the Layers panel and choose Zoom to layer.

6. In the Layers panel uncheck the boxes of all layers except Google Satellite.

7. Go to the Processing Toolbox.

8. Choose Raster tools | Generate XYZ tiles (MBTiles)

9. In the Generate XYZ tiles (MBTiles) dialogue choose for Extent Use Layer Extent...

10. Choose Bangula_study_area and click OK.

11. Set the minimum and maximum zoom level to 17.

If you give a range here, it will create MBTiles for different zoom levels. This will make the file bigger, but navigation smoother when you zoom in and out a lot. Most often in the field you only want the detailed level. Therefore here we choose just zoom level 17.

12. Save the layer to the dedicated folder with project files as Satellite.mbtiles. Leave other settings at default.

Note that the mbtiles can't be saved directly to a GeoPackage. We'll later drag it to the GeoPackage.

13. Click Run. Click Close after processing.

14. In the Browser panel drag the Satellite.mbtiles raster to the Bangula_groundwater_survey GeoPackage.

15. Drag the Satellite layer from the Bangula_groundwater_survey GeoPackage to the map canvas.

16. Repeat the steps for OSM Standard.

17. Save the project.

Now the online and offline layers are ready.

In the next section we're going to add the survey layer.