General Tools¶

Scale Dependent Rendering¶

Scale-dependent rendering allows you to specify the minimum and maximum scales at which a layer will be visible. To set scale-dependent rendering, open the Properties dialog by double-clicking on the layer in the legend. On the General tab, click on the Scale dependent visibility checkbox to activate the feature, then set the minimum and maximum scale values.

You can determine the scale values by first zooming to the level you want to use and noting the scale value in the QGIS status bar.

Controlling Map Rendering¶

Map rendering can be controlled in the various ways, as described below.

Measure length, areas and angles¶

^{Measure Line}: QGIS is able to measure real distances between given points according to a defined ellipsoid. To configure this, choose menu option Settings ‣ Options, click on the Map tools tab and select the appropriate ellipsoid. There, you can also define a rubberband color and your preferred measurement units (meters or feet) and angle units (degrees, radians and gon). The tool then allows you to click points on the map. Each segment length, as well as the total, shows up in the measure window. To stop measuring, click your right mouse button.

Figure Measure 1:

Measure Distance (Gnome)

^{Measure Area}: Areas can also be measured. In the measure window, the accumulated area size appears. In addition, the measuring tool will snap to the currently selected layer, provided that layer has its snapping tolerance set (see section Setting the Snapping Tolerance and Search Radius). So, if you want to measure exactly along a line feature, or around a polygon feature, first set its snapping tolerance, then select the layer. Now, when using the measuring tools, each mouse click (within the tolerance setting) will snap to that layer.

Figure Measure 2:

Measure Area (Gnome)

^{Measure Angle}: You can also measure angles. The cursor becomes cross-shaped. Click to draw the first segment of the angle you wish to measure, then move the cursor to draw the desired angle. The measure is displayed in a pop-up dialog.

Figure Measure 3:

Measure Angle (Gnome)

Select and deselect features¶

The QGIS toolbar provides several tools to select features in the map canvas. To select one or several features, just click on and select your tool:

• ^{Select Single Feature}
• ^{Select Features by Rectangle}
• ^{Select Features by Polygon}
• ^{Select Features by Freehand}
• ^{Select Features by Radius}

To deselect all selected features click on ^{Deselect features from all layers}.

^{Select feature using an expression} allow user to select feature using expression dialog. See Expressions chapter for some example.

Users can save features selection into a New Memory Vector Layer or a New Vector Layer using Edit ‣ Paste Feature as ... and choose the mode you want.

Grid¶

^Grid allows you to add a coordinate grid and coordinate annotations to the map canvas.

Figure Decorations 1:

The Grid Dialog

1. Select from menu View ‣ Decorations ‣ Grid. The dialog starts (see figure_decorations_1).
2. Activate the Enable grid checkbox and set grid definitions according to the layers loaded in the map canvas.
3. Activate the Draw annotations checkbox and set annotation definitions according to the layers loaded in the map canvas.
4. Click [Apply] to verify that it looks as expected.
5. Click [OK] to close the dialog.

Copyright Label¶

^{Copyright label} adds a copyright label using the text you prefer to the map.

Figure Decorations 2:

The Copyright Dialog

1. Select from menu View ‣ Decorations ‣ Copyright Label. The dialog starts (see figure_decorations_2).
2. Enter the text you want to place on the map. You can use HTML as shown in the example.
3. Choose the placement of the label from the Placement combo box.
4. Make sure the Enable Copyright Label checkbox is checked.
5. Click [OK].

In the example above, which is the default, QGIS places a copyright symbol followed by the date in the lower right-hand corner of the map canvas.

North Arrow¶

^{North Arrow} places a simple north arrow on the map canvas. At present, there is only one style available. You can adjust the angle of the arrow or let QGIS set the direction automatically. If you choose to let QGIS determine the direction, it makes its best guess as to how the arrow should be oriented. For placement of the arrow, you have four options, corresponding to the four corners of the map canvas.

Figure Decorations 3:

The North Arrow Dialog

Scale Bar¶

^{Scale Bar} adds a simple scale bar to the map canvas. You can control the style and placement, as well as the labeling of the bar.

Figure Decorations 4:

The Scale Bar Dialog

QGIS only supports displaying the scale in the same units as your map frame. So if the units of your layers are in meters, you can’t create a scale bar in feet. Likewise, if you are using decimal degrees, you can’t create a scale bar to display distance in meters.

To add a scale bar:

1. Select from menu View ‣ Decorations ‣ Scale Bar. The dialog starts (see figure_decorations_4).
2. Choose the placement from the Placement combo box.
3. Choose the style from the Scale bar style combo box.
4. Select the color for the bar Color of bar or use the default black color.
5. Set the size of the bar and its label Size of bar .
6. Make sure the Enable scale bar checkbox is checked.
7. Optionally, check Automatically snap to round number on resize.
8. Click [OK].

Html annotations¶

The ^{Html Annotation} tools in the attribute toolbar provides the possibility to place the content of an html file in a balloon on the QGIS map canvas. Using the Html Annotation tool, click into the map canvas and add the path to the html file into the dialog.

SVG annotations¶

The ^{SVG Annotation} tool in the attribute toolbar provides the possibility to place an SVG symbol in a balloon on the QGIS map canvas. Using the SVG Annotation tool, click into the map canvas and add the path to the SVG file into the dialog.

Form annotations¶

Additionally, you can also create your own annotation forms. The ^{Form Annotation} tool is useful to display attributes of a vector layer in a customized Qt Designer form (see figure_custom_annotation). This is similar to the designer forms for the Identify features tool, but displayed in an annotation item. Also see this video https://www.youtube.com/watch?v=0pDBuSbQ02o from Tim Sutton for more information.

Figure annotation 2:

Customized qt designer annotation form

Creating a Bookmark¶

To create a bookmark:

1. Zoom or pan to the area of interest.
2. Select the menu option View ‣ New Bookmark or press Ctrl-B.
3. Enter a descriptive name for the bookmark (up to 255 characters).
4. Press Enter to add the bookmark or [Delete] to remove the bookmark.

Note that you can have multiple bookmarks with the same name.

Working with Bookmarks¶

To use or manage bookmarks, select the menu option View ‣ Show Bookmarks. The Geospatial Bookmarks dialog allows you to zoom to or delete a bookmark. You cannot edit the bookmark name or coordinates.

Zooming to a Bookmark¶

From the Geospatial Bookmarks dialog, select the desired bookmark by clicking on it, then click [Zoom To]. You can also zoom to a bookmark by double-clicking on it.

Deleting a Bookmark¶

To delete a bookmark from the Geospatial Bookmarks dialog, click on it, then click [Delete]. Confirm your choice by clicking [Yes], or cancel the delete by clicking [No].

Embedding layers¶

The following dialog allows you to embed layers from other projects. Here is a small example:

1. Press to look for another project from the Alaska dataset.
2. Select the project file grassland. You can see the content of the project (see figure_embed_dialog).
3. Press Ctrl and click on the layers grassland and regions. Press [OK]. The selected layers are embedded in the map legend and the map view now.

Figure Nesting 1:

Select layers and groups to embed

While the embedded layers are editable, you can’t change their properties like style and labeling.

Removing embedded layers¶

Right-click on the embedded layer and choose ^Remove.