QField allows to digitize, edit and delete point, line and polygon features while in the field.
جمع آوری ویژگیها¶
To start digitizing new features, enable the Edit mode by clicking on the pencil icon in the side dashboard and selecting the layer within which you want to add new features.
The current layer within which features are to be added is highlighted in green.
Adding point features¶
Navigate the crosshair in the center of the screen to the desired location and click the Plus (+) button at the lower right of the screen to confirm the creation of a new point feature.
You can use the lock to position button to force the crosshair to center on your location if you have enabled positioning.
Adding line or polygon features¶
Navigate the crosshair in the center of the screen to the desired start of the line or polygon and click the Plus (+) button at the lower right of the screen to add the first node.
Proceed with adding points to form you line or polygon by clicking the Plus (+) button each time you want to add a new node.
Click the Minus (-) button to remove the last added node.
When you have added a least 2 nodes for a line or 3 nodes for a polygon, a Save button will appear. Click on it to finish your geometry.
While digitizing, you can click the (x) button to cancel the current feature creation.
QField insures that digitized geometries will not have duplicate vertices and respects the geometry precision settings from the currently selected layer.
After digitizing a geometry, the attribute form will appear allowing you to edit attribute values for the newly-added feature.
You can supress the attribute form upon feature addition via a configuration option for a given layer via its properties dialog in QGIS
Remember attribute values¶
For quick collection of rather homogeneus datasets, it is crucial to not having to enter the same attribute values over an over. The checkboxes at the right of every attribute allow remembering of the last entered value for each attribute individually so that the next time you will add a feature on the same layer, these attributes will be automatically pre-filled.
To edit the geometry of pre-existing features, enable the Edit mode by tapping on the pencil icon in QField's side dashboard.
Once in edit mode, a new Edit geometry button will appear in the title bar of an identified feature form. Clicking on the button will activate the geometry editor environment which offers four tools:
- A vertex editor tool;
- A geometry split tool;
- A geometry reshape tool; and
- A geometry ring tool.
The vertex editor allows you to move or delete pre-existing vertices as well as adding new vertices to geometries.
The split tool allows you to split line and polygon geometries into two halves, one of which will become a new feature of its own.
The reshape tool allows you to change line and polygon geometries by drawing shapes which will result a reshaped line following the edge of the drawn shape or a polygon with the drawn shapped used to clip or expand the geometry.
The ring tool allows you to digitize rings (i.e. holes) into polygon geometries. Once a ring is created, QField will offer the possibility of filling the ring with a new feature.
Demonstration of geometries editing¶
A video demonstration of some editing possibilities:
QField allows you to merge features and their geometries into a single feature. To do so, identify two (or more) features on the map, select them in the features list and merge them by selecting the Merge Selected Features in the Menu (⁝) Button.
The freehand digitizing mode allows you to "draw" lines and polygons using their stylus pen or mouse. The mode is available for line and polygon feature additions as well as the above-mentioned geometry editor's rings, split, and reshape tools.
The freehand digitizing mode is activated through a new toolbar button which appears when QField is set to editing mode and a stylus pen or a mouse is hovering the map canvas while a line or polygon vector is selected.
If topological editing is activated on the project QGIS before exporting for QField, shared nodes of neighbouring geometries are modified together when moving / deleting vertices and additional vertices are added to segments when a new node is added from neightbouring geometries.
Multi-editing of attributes¶
QField allows you to select multiple features and edit their attributes all at once. In some cases, it can result in very efficient worflows. To do so, identify two (or more) features on the map, select them in the features list and merge them by selecting the Edit feature button in the list's title bar.
Deleting a feature is done by selecting the Delete feature action in the feature form's 3-dot menu.
QField also allows you to delete multiple features at a time. To do so, first identify the features by short tapping on the relevant parts of the map. Then activate the multi-selection mode by long pressing on one of the features you want to delete. When checkbox appears next to the feature names, select further features to delete (you can tap on the map to add more features too). Once done, select the Delete Selected Feature(s) action in the features list 3-dot menu.
While digitizing new features, new points can be snapped to existing geometries.
All configuration can be done in Project > Snapping Settings
It is possible to snap new points
- only to nodes of existing geomtries
- only to segments of existing geomtries
- to nodes and segments of existing geomtries
Snapping to layers¶
It is also possible to only snap to one or a few layers.
The snapping tolerance can be specified in map units or pixels.
In almost any case, the units should be set to pixels. We made good experiences with a tolerance value of 20.