When to use it?
When you need
to create features (polygons,
points) representing something of your interest (such as forest areas,
streets, fire spots) over a Satellite image for example or over other
type of layer, or inserting/updating features in an existing layer.
The Edit plug-in allows you to edit a(new) ayer using a small set of tools. It is possible to insert/move/delete/update using these tools over a reference layer.
Firstly, select and draw the layer you will use a a background to create the features (geometries). If the edition is on an existing layer, select and draw it too. And keep it selected.
To use this plugin, go to Plugins->Edition Tools in order to have access to the menu bar.
1) To turn on/off the edit menu bar, click on
2) To Create an new Layer, click on and enter the parameters for the new layer (Shape/PostGis).
3) To save one or more geometries created or edited, click . After saving them, their attributes can be inserted/updated through .
4) To Cancel all Edition not saved yet, click on .
5) Undo the last edit made or redo to the last edit returned .
Creating and Manipulating Geometries
After turning on the tools clicking on and having a layer selected at the Map Display, choose the appropriate tool.
1) Creating Polygons
- To create a Polygon just click from point to point or click and drag to build the shape of the polygon, ending the polygon creation with the right mouse button.
2) Creating Lines
- To create a Line just click from point to point or click and drag to build the shape of the line, ending the line creation with the right mouse button.
3) Creating Points
- To create a Point just click over the map on the desired position.
From time to time save the geometries, clicking on .
Note that the geometry type available match the layer geometry type. It means for example, that it is impossible to create a Point in a layer of Polygon/MultiPolygon.
4) Features Attributes
- It allows to assign/edit values of attributes of each geometry (feature) selected.
- Active the tool, then the '?' sign will appear, so select the desired geometry (feature) by clicking on it and fill the popup interface with the attribute values. At the end, press Save (or Cancel).
- Select the next geometry and do the same.
- To persist all the changes click on . Press Esc to gave up the changes.
5) Moving Geometries . ESC button will undo the moving action.
- To move a geometry to another position, click and drag it. Only its outline is shown in the new position. More than one geometry can be repositioned.
- To persist the new positions click on and the geometries will be completely visualized.
6) Vertex Tool : Move (Click and Drag), Add (Double Click), Remove (Shift+Click)
- It allows changing, adding or removing vertices in geometries.
- To use it, just select the tool, click on a specific geometry to view the outline with its vertices and points. Then move, add or delete a vertex and observe the changes.
- To define whether a vertex can be moved, a blue circle is displayed over it, where clicking and dragging the vertex makes the move.
- To define whether a vertex can be created, a green circle is displayed over the contour, where with a double click a new vertex is created.
- To remove a vertex simply locate an existing one and perform the `Shift + Click` combination, removing the vertex.
- To persist the changes click on otherwise press ESC button.
7) Deleting Geometries
- To select one geometry to be deleted, click over it and observe the hatched visual.
- To select more than one, use 'Crtl + Click' over the geometry.
- To undo the selection(s) click on ESC button.
- To persist the delete action click on .
8) Snap On
- Snapping tolerance is the distance Edit Plugin uses to search for the closest vertex you are trying to connect to when you set a new vertex or move an existing vertex.
- It is necessary to select which layer from the list of available ones you want to use to snap to. This layer must be visualized together with the current layer.
9) Aggregate Area
- It allows to aggregate an new area to a geometry.
- Without the need to select the geometry, just draw the area to be aggregated, clicking point to point or clicking and dragging to form the new area, ending with a double click to view the new contour. The new area must cross the target polygon.
- To persist the aggregation, clicking on , otherwise press ESC button.
10) Subtract Area
- It allows to subtract an area of a geometry.
- Without the need to select the geometry, just draw the area to be subtracted, clicking point to point or clicking and dragging to form the area, ending with a double click to view the area contour. The area must cross the target polygon.
- To persist the action it is necessary to save, clicking on , otherwise press ESC button.
11) Merge geometries
- Allows to join geometries that have some intersection area, keeping the attribute of only one.
- Select the geometries to be merged using the main menu bar, [Ctrl]+click over the geometries and keep in mind the 'id' of the one that will keep the attributes.
- Select the Merge tool and on the popup msg choose the 'id' that will keep the attributes, click on OK.
- To persist the merge action, click on , otherwise press ESC. button.
12) Split Polygon
- It allows split a geometry in two, using an edited line on it, maintaining the attributes for the two geometries, except the ID of one of them.
- Select the geometry to be splitted using this tool (it will be highlighted in green).
- Click on split tool
- Now just draw the line that will be used to split the geometry, clicking point to point or clicking and dragging, ending with double click to see the new contour of the already divided geometries.
- To persist the split action, click on , otherwise press ESC button.