L’élément Carte

The map item is the main frame that displays the map you’ve designed in the map canvas. Use the Add Map tool following items creation instructions to add a new map item that you can later manipulate the same way as exposed in Interacting with layout items.

By default, a new map item shows the current status of the map canvas with its extent and visible layers. You can customize it thanks to the Item Properties panel. Other than the items common properties, this feature has the following functionalities:

Onglet Propriétés d’une carte

Propriétés principales

In the Main properties group (see figure_layout_map) of the map Item Properties panel, available options are:

• The Update Preview button to refresh the map item rendering if the view in map canvas has been modified. Note that most of the time, the map item refresh is automatically triggered by the changes;

• The Scale to manually set the map item scale;

• The Map rotation allows you to rotate the map item content clockwise in degrees. The rotation of the map canvas can be imitated here;

• The CRS allows you to display the map item content in any CRS. It defaults to Use project CRS;

• Draw map canvas items lets you show in the print layout annotations that are placed on the main map canvas.

Couches

By default, map item appearance is synced with the map canvas rendering meaning that toggling visibility of the layers or modifying their style in the Layers Panel is automatically applied to the map item. Because, like any other item, you may want to add multiple map items to a print layout, there’s a need to break this synchronization in order to allow showing different areas, layer combinations, at different scales… The Layers properties group (see figure_layout_map_layers) helps you do that.

Map Layers group

If you want to keep the map item consistent with an existing map theme, check Follow map theme and select the desired theme in the drop-down list. Any changes applied to the theme in QGIS” main window (using the replace theme function) will automatically affect the map item. If a map theme is selected, the Lock styles for layers option is disabled because Follow map theme also updates the style (symbology, labels, diagrams) of the layers.

To lock the layers shown in a map item to the current map canvas visibility, check Lock layers. When this option is enabled, any changes on the layers” visibility in QGIS” main window will not affect the layout’s map item. Nevertheless, style and labels of locked layers are still refreshed according to QGIS” main window. You can prevent this by using Lock styles for layers.

Instead of using the current map canvas, you can also lock the layers of the map item to those of an existing map theme: select a map theme from the ^{Set layer list from a map theme} drop-down button, and the Lock layers is activated. The set of visible layers in the map theme is from now on used for the map item until you select another map theme or uncheck the Lock layers option. You then may need to refresh the view using the ^{Refresh view} button of the Navigation toolbar or the Update Preview button seen above.

Note that, unlike the Follow map theme option, if the Lock layers option is enabled and set to a map theme, the layers in the map item will not be refreshed even if the map theme is updated (using the replace theme function) in QGIS” main window.

Locked layers in the map item can also be data-defined, using the icon beside the option. When used, this overrides the selection set in the drop-down list. You need to pass a list of layers separated by | character. The following example locks the map item to use only layers layer 1 and layer 2:

concat ('layer 1', '|', 'layer 2')

Emprise

The Extents group of the map item properties panel provides the following functionalities (see figure_layout_map_extents):

Map Extents group

The Extents area displays X and Y coordinates of the area shown in the map item. Each of these values can be manually replaced, modifying the map canvas area displayed and/or map item size. Clicking the Set to Map Canvas Extent button sets the extent of the layout map item to the extent of the main map canvas. The button View Extent in Map Canvas does exactly the opposite; it updates the extent of the main map canvas to the extent of the layout map item.

You can also alter a map item extent using the ^{Move item content} tool: click-and-drag within the map item to modify its current view, keeping the same scale. With the tool enabled, use the mouse wheel to zoom in or out, modifying the scale of the shown map. Combine the movement with Ctrl key pressed to have a smaller zoom.

Controlled by atlas

The Controlled by atlas group properties is available only if an atlas is active in the print layout. Check this option if you want the map item being ruled by the atlas; when iterating over the coverage layer, the map item extent is panned/zoomed to the atlas feature following:

• Margin around features: zooms to the feature at the best scale, keeping around each a margin representing a percentage of the map item width or height. The margin can be the same for all features or set variable, e.g., depending on map scale;

• Predefined scale (best fit): zooms to the feature at the project predefined scale where the atlas feature best fits;

• Fixed scale: atlas features are panned from one to another, keeping the same scale of the map item. Ideal when working with features of same size (e.g., a grid) or willing to highlight size differences among atlas features.

Graticules

With grids, you can add, over your map, information relative to its extent or coordinates, either in the map item projection or a different one. The Grids group provides the possibility to add several grids to a map item.

• With the and buttons you can add or remove a selected grid;

• With the and buttons you can move up and down a grid in the list, hence move it on top or bottom of another one, over the map item.

Double-click the added grid to rename it.

Fenêtre des Graticules de Carte

After you add a grid, you can activate the checkbox Draw grid to allow overlaying the grid onto the map item. Press the Modify Grid… button to access configuration options.

Grid Appearance

As grid type, you can specify to use a:

• Solid: shows a line across the grid frame. The Line style can be customized using color and symbol selector widget;

• Cross: displays segment at the grid lines intersection for which you can set the Line style and the Cross width;

• Markers: only displays customizable markers symbol at grid lines intersection;

• or Frame and annotations only.

Other than the grid type, you can define:

• the CRS which could not be the same as the map item’s;

• the Interval between two consecutive grid references in X and Y directions;

• the Interval Units to use for the grid references, in Map units, Millimeters or Centimeters;

• an Offset from the map item edges, in X and Y directions;

• and the Blend mode of the grid (see Modes de fusion) when compatible.

Paramètres d’affichage des graticules

Grid Frame

There are different options to style the frame that holds the map. Following options are available: No Frame, Zebra, Interior ticks, Exterior ticks, Interior and Exterior ticks and Line border. Also you can choose to set visible or not each side of the grid frame.

When compatible, it’s possible to set the Frame size, Frame line thickness, Frame fill colors. With Latitude/Y only and Longitude/X only settings in the divisions section you have the possibility to prevent a mix of latitude/Y and longitude/X coordinates showing on a side when working with rotated maps or reprojected grids.

Fenêtre du Cadre du Graticule

Coordinates

The Draw coordinates checkbox allows you to add coordinates to the map frame. You can choose the annotation numeric format, the options range from decimal to degrees, minute and seconds, with or without suffix, aligned or not and a custom format using the expression dialog.

You can choose which annotation to show. The options are: show all, latitude only, longitude only, or disable(none). This is useful when the map is rotated. The annotation can be drawn inside or outside the map frame. The annotation direction can be defined as horizontal, vertical ascending or vertical descending.

Finally, you can define the annotation font, font color, distance from the map frame and the precision of the drawn coordinates.

Fenêtre des Coordonnées d’affichage du graticule

Aperçus

Sometimes you may have more than one map in the print layout and would like to locate the study area of one map item on another one. This could be for example to help map readers identify the area in relation with its larger geographic context shown in the second map.

The Overviews group of the map panel helps you create the link between two different maps extent and provides the following functionalities:

Map Overviews group

To create an overview, select the map item on which you want to show the other map item’s extent and expand the Overviews option in the Item Properties panel. Then press the button to add an overview.

Initially this overview is named “Overview 1” (see Figure_layout_map_overview). You can:

• Rename it with a double-click;

• With the and buttons, add or remove overviews;

• With the and buttons, move up and down an overview in the list, hence move it on top or bottom of another one, over the map item.

Then select the overview item in the list and check the Draw « <name_overview> » overview to enable the overview drawing over the selected map frame. You can customize it with:

• La liste combo Cadre de carte peut être utilisée pour sélectionner l’élément carte dont les extensions seront affichées sur l’élément carte présent.

• Le Style du cadre vous permet de changer le style du cadre de l’aperçu.

• Le Mode de fusion vous permet de définir différents modes de fusion pour créer une transparence.

• L’option Inverser l’aperçu crée un masque sur l’emprise de l’autre zone de carte qui apparaît clairement tandis que le reste de la carte est mis en transparence en utilisant le mode de fusion choisi.

• L’option Centrer sur l’aperçu paramètre l’emprise du cadre d’aperçu au centre de la carte d’aperçu. Vous pouvez activer uniquement un seul élément d’aperçu au centre lorsque vous avez plusieurs aperçus.