I want to collect data on crop species affected by diseases using QField. I want to create a widget so that I can have a dropdown list of the different crop species. In theory, if I were to export this project onto QField and collect data, I would select the crop species from the drop down list. Most of the answers I've found suggest changing the widget type to relation reference and link it to a CSV, but my data is already in the attribute table. Has anyone done this before? Which widget type should I use? Or any tutorials?
[GIS] Creating a dropdown widget in QGIS for QField project
qfieldqgiswidget
Related Solutions
The widget types Value Relation and Relation Reference have a large overlap. Certain functionality - like (chained) filtering which you are using here - is only implemented for one of the two. So yes, this is a valid/reasonable approach.
There is no simple way (yet) but it wouldn't be much effort to hide this button with an option in the widget configuration dialog. You can file a feature request, create a pull request or help improving QGIS by funding somebody to implement this feature.
First I recommend to use QGIS 3.4.2, because QGIS 2.18.26 did not provide the desired results.
If your species data are saved in a CSV file, load the data into the QGIS as a table from Add vector layer NOT from Add delimited text layer along with the vector layer that you want to populate its field with the species information as follows:
- Use Add vector layer to load both the vector file and the CSV file
- Start Editing of the vector file -> Add a new field in the attribute table of type
Textto populate it with information from the CSV file'
- Go to the
Layer properties of the vector layer -> Fields, and change theEdit widgetfromText EdittoValue Relation
Under Select Layer, Key Column, Value Column, select the CSv file that contains the species information, use ID column as Key Column, and Species Name as Value Column as shown below, and click OK.
Now Go to to the attribute Table of the vector layer -> Species Column -> You will see a drop down list coming from the CSV file in which you can choose the species names.
Here is the output:
Best Answer
With your layer already loaded into the QGIS TOC (the layer that contains all the possible values), you should go to properties > attributes form > Widget type and select a «Value Map type». Then, click on Load Data from Layer button and on the upcoming window, you should select the layer as well as the column where to get the possible values from.
Then, via the QField Sync plugin, you can export the project to QField, so the designed form will be also available from your mobile device. Hope this helps.