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When you need help on a specific topic, you can access context help via the [Help] button available in most dialogs — please note that third-party plugins can point to dedicated web pages.
QGIS provides by default many panels to work with. Some of these panels are described below while others may be found in different parts of the document. A complete list of default panels provided by QGIS is available at Pannelli.
The layers Panel lists all the layers in the project and helps you manage their visibility. A layer can be selected and dragged up or down in the legend to change the Z-ordering. Z-ordering means that layers listed nearer the top of the legend are drawn over layers listed lower down in the legend.
Nota
Questo comportamento di default può essere cambiato tramite il pannello Layer Order.
In cima al Pannello dei Layer, una barra degli strumenti ti permette di:
Filtra la legenda in base al contenuto della mappa: solo i layers che ricadono nell’area in visualizzazione vengono elencati in modo completo, gli altri restano ma hanno simbologia nulla, in questo modo viene evidenziato quali sono i layer di interesse nella zona visualizzata.
Espandi tutti or Racchiudi tutti layers e gruppi nel layers panel.
Nota
Tools to manage the layers panel are also available to layout the map and legend items of the print composer
The button allows you to add Presets views in the legend. Presets are a way to save and easily restore a combination of layers with their current style. To add a preset view, just set visible the layers you want, with their desired symbology, and click on button. Choose Add Preset... from the drop-down menu and give a name to the preset. The added preset is listed at the bottom of the drop-down menu and is recalled by clicking on it.
The Replace Preset ‣ option helps you overwrite a preset content with the current map view while the Remove Current Preset button deletes the active preset.
All the added presets are also present in the map composer in order to allow you to create a map layout based on your specific views (see Proprietà principali).
I layers presenti nella finestra della legenda possono essere organizzati in gruppi. Ciò può essere fatto in due modi:
Premi l’icona per aggiungere un nuovo gruppo. Digita un nome per il gruppo e premi Enter. Ora clicca su un layer esistente e trascinalo nel gruppo.
To bring a layer out of a group, you can drag it out, or right click on it and choose Move to top-level; the layer is placed at the same level than the group it was inside. Groups can also be nested inside other groups.
Puoi usare la casella di controllo di un gruppo per mostrare/nascondere tutti i layer del gruppo con un singolo click.
Enabling the Mutually Exclusive Group option you can make a group have only one layer visible at the same time. Whenever a layer within the group is set visible the others will be toggled not visible.
It is possible to select more than one layer or group at the same time by holding down the Ctrl key while selecting the layers with the left mouse button. You can then move all selected layers to a new group at the same time.
You may also delete more than one layer or group at once by selecting several items with the Ctrl key and pressing Ctrl+D afterwards. This way, all selected layers or groups will be removed from the layers list.
From the Layers panel, you have shortcuts to easily and quickly edit the layer rendering. Right-click on a vector layer and select Styles ‣ in the list in order to:
copiare lo stile corrente o, se applicabile, incollare uno stile copiato da un altro layer
Nota
The previous options are also available for raster layer.
Whether the features in the vector layer have all the same unique symbol or they are classified (in that case, the layer is displayed in a tree structure with each class as sub-item), the following options are available at layer level or class level:
Suggerimento
Condividere rapidamente lo stile di un layer
From the context menu, copy the style of a layer and paste it to a group or a selection of layers: the style is applied to all the layers that are of the same type (vector vs raster) as the original layer and, in case of vector, have the same geometry type (point, line or polygon).
There is a panel that allows you to define an independent drawing order for the layers panel. You can activate it in the menu Settings ‣ Panels ‣ Layer Order Panel. This feature allows you to, for instance, order your layers in order of importance, but still display them in the correct order (see figure_layer_order; you can notice that the airports features are displayed over the alaska polygon despite their layers placement in the Layers panel). Unchecking the Control rendering order box underneath the list of layers will cause a revert to default behavior.
This panel is somehow a shortcut to some of the features of the layer properties dialog. It indeed offers you a quick and handy way to define the rendering and the behavior of a layer, and to visualize its effects without opening the layer properties dialog.
Besides avoiding you dealing with the modal and blocking dialog of the layer properties, it also avoids you cluttering the screen with features dialogs given that it embeds most of them (color selector, effects properties, rule edit, label substitution...): e.g., clicking color buttons inside the layer style panel causes the color selector dialog to be opened inside the layer style panel itself rather than as a separate dialog.
Dall’elenco a discesa dei layers presenti nel Layers Panel, selezionare un elemento e:
Another powerful feature of this panel is the Live update checkbox. Tick it and your changes are automatically rendered in the map canvas as you go on. You no longer need to hit the [Apply] button.
Suggerimento
Add custom tabs to the Layer Styling panel
Using PyQGIS, you can set new tabs to manage layer properties in the Layer Styling Panel. See https://nathanw.net/2016/06/29/qgis-style-dock-part-2-plugin-panels/ for an example.
This panel can show some statistics on a specific vector layers. The panel allows users to choose:
Statistic information available are (depending on the field’s type):
Tabella: Statistiche disponibili per ciascun tipo di campo
In QGIS, you can use an overview panel that provides a full extent view of layers added to it. Within the view is a rectangle showing the current map extent. This allows you to quickly determine which area of the map you are currently viewing. Note that labels are not rendered to the map overview even if the layers in the map overview have been set up for labelling. If you click and drag the red rectangle in the overview that shows your current extent, the main map view will update accordingly.
When loading or processing some operations, you can track and follow messages that appear in different tabs using the Log Messages Panel. It can be activated using the most right icon in the bottom status bar.
For each layer being edited, this panel shows the list of actions done, allowing to quickly undo a set of actions by simply selecting the action listed above. More details at Undo and Redo edits.
In modo predefinito, QGIS visualizza tutti i layer visibili ogni volta che la mappa viene aggiornata. La mappa viene aggiornata ogni volta che:
QGIS consente di controllare il processo di visualizzazione in diversi modi.
Scale-dependent rendering allows you to specify the minimum and maximum scales at which a layer (raster or vector) 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, tick the Scale dependent visibility checkbox and enter the Minimum (exclusive) and Maximum (inclusive) scale values.
You can also activate the scale dependent visibility on a layer from the Layers panel. Right-click on the layer and in the context menu, select Set Layer Scale Visibility.
The Set to current canvas scale button helps you use the current map canvas scale as boundary of the range visibility.
Nota
When a layer is not rendered in the map canvas due to the map scale out of its visibility scale range, the layer is greyed in the Layers panel and a new option Zoom to Visible Scale appears in the layer context menu. Select it and the map is zoomed to the layer’s nearest visibility scale.
Puoi controllare la visualizzazione della mappa in molti modi diversi, come descritto di seguito.
To suspend rendering, click the Render checkbox in the lower right corner of the status bar. When the Render checkbox is not checked, QGIS does not redraw the canvas in response to any of the events described in section Visualizzazione. Examples of when you might want to suspend rendering include:
Se la casella di controllo Aggiorna è spuntata, la visualizzazione e l’aggiornamento della mappa saranno immediati.
You can set an option to always load new layers without drawing them. This means the layer will be added to the map, but its visibility checkbox in the legend will be unchecked by default. To set this option, choose menu option Settings ‣ Options and click on the Rendering tab. Uncheck the By default new layers added to the map should be displayed checkbox. Any layer subsequently added to the map will be off (invisible) by default.
To stop the map drawing, press the ESC key. This will halt the refresh of the map canvas and leave the map partially drawn. It may take a bit of time between pressing ESC and the time the map drawing is halted.
Nota
Attualmente non si può interrompere la visualizzazione in corso: questa opzione è stata disabilitata nella porta Qt4 a causa di diversi problemi dell’interfaccia utente (UI).
QGIS ha una opzione per modificare la qualità della restituzione nella visualizzazione della mappa. Nel menu Impostazioni ‣ Opzioni, click sulla scheda Visualizzazione e seleziona o deseleziona Rendi le linee meno irregolari a spese delle prestazioni.
Ci sono alcune opzioni che ti permettono di velocizzare la visualizzazione. Apri la finestra di dialogo di QGIS Impostazioni ‣ Opzioni, vai alla scheda Visualizzazione e seleziona o deseleziona le seguenti caselle di controllo:
Visualizza i layers in parallelo usando più processori della CPU e poi imposta Numero massimo di processori da utilizzare.
La costruzione della mappa avviene in background su un’immagine separata e ad ogni Intervallo di aggiornamento della mappa, il contenuto di questa immagine (fuori schermo) verrà utilizzato per aggiornare la rappresentazione della visualizzazione sullo schermo. Tuttavia, se la costruzione termina più velocemente di questa durata, la visualizzazione avverrà immediatamente.
The select color dialog will appear whenever you push the icon to choose a color. The features of this dialog depends on the state of the Use native color chooser dialogs parameter checkbox in Settings ‣ Options ‣ General menu. When checked, the color dialog used is the one of the OS being used. Otherwise, QGIS custom color chooser is used.
Suggerimento
Dynamically change the color with the live-updating option
Check the Use live-updating color chooser dialogs option in the Settings ‣ Options ‣ General menu to have the color applied to your items as soon as you pick it in the color chooser dialog.
The custom color chooser dialog has four different tabs which allow you to select colors by color ramp, color wheel, color swatches or color picker (not available under ).
Whatever method you use, the selected color is always described through color sliders for HSV (Hue, Saturation, Value) and RGB (Red, Green, Blue) values. The color is also identifiable as a HTML notation. Finally, there is an opacity slider to set transparency level.
Modifying a color is as simple as clicking in the color wheel or ramp or in any of the color parameters sliders. You can adjust such parameters with the spinbox beside or, handy, scrolling the mouse wheel over the corresponding slider. You can also typeset the color html notation.
The dialog also provides a visual comparison between the current (applied to widget) and the new (being selected) colors. Thanks to drag-and-drop, any of these colors can be saved in a slot for an easy access.
With color ramp or color wheel tab, you can browse to all possible color combinations and apply it to the item. In the color swatches tab, you can choose from a preselected list of color palettes:
The latest palettes can be modified thanks to the and buttons at the bottom of the frame. The ... button nearby the palette combobox also offers several options to:
copia, incolla, importa o esporta colori
Another option is to use the color picker which allows you to sample a color from under your mouse pointer at any part of QGIS or even from another application by pressing the space bar. Please note that the color picker is OS dependent and is currently not supported by macOS.
Suggerimento
Modifica veloce del colore
Click the drop-down arrow at the right of the color box button to display a widget for a quick color selection, either in the color wheel or from existing color palettes. You can also use it to copy or paste a color.
QGIS offers different options for special rendering effects with these tools that you may previously only know from graphics programs. Blending modes can be applied on layers, on features but also on print composer items:
Normale: Questa è la modalità di fusione predefinita che usa il canale alpha del pixel più in alto fondendolo con quello sotto. I colori non sono quindi mescolati.
Schiarisci: Questo seleziona il valore massimo di ogni componente dal basso verso l’alto. Fai attenzione che Il risultato può apparire frastagliato e duro.
Luce intensa: Questa modalità è simile alla modalità sovrapponi. Proietta una luce molto intensa su tutta l’immagine.
QGIS fornisce strumenti per fare zoom e per spostarti alla tua area di interesse
Apart from using the pan and zoom-in / zoom-out icons on the toolbar with the mouse, navigating can also be done with the mouse wheel, spacebar and the arrow keys. A Zoom factor can be set under the Settings ‣ Options ‣ Map tools menu to define the scale behavior while zooming.
You can press the mouse wheel to pan inside of the main window (on macOS, you may need to hold cmd key). You can roll the mouse wheel to zoom in and out on the map; the mouse cursor position will be the center of the zoomed area of interest. Holding down Ctrl while rolling the mouse wheel results in a finer zoom.
Panning the map is possible with the arrow keys. Place the mouse cursor inside the map area, and click on the right arrow key to pan east, left arrow key to pan west, up arrow key to pan north, and down arrow key to pan south.
You can also use the space bar to temporarily cause mouse movements to pan the map. The PgUp and PgDown keys on your keyboard will cause the map display to zoom in or out following the zoom factor set. Pressing Ctrl + or Ctrl - also performs an immediate zoom in/out on the map canvas.
When certain map tools are active (Identify, Measure...), you can perform a zoom by holding down Shift and dragging a rectangle on the map to zoom to that area. This is enabled for the map tools which are not selection tools (since they use Shift for adding to selection) nor edit tools.
QGIS effettua misure delle geometrie vettoriali in quattro modi:
La misurazione opera nei sistemi di coordinate proiettate piane (ad esempio UTM) e con coordinate geografiche. I primi tre metodi di misura si comportano nello stesso modo con riferimento ai settaggi globali di proiezione.
However, neither the identify tool nor the field calculator will transform your data to the project CRS before measuring. If you want to achieve this, you have to use the vector analysis tool: Vector ‣ Geometry Tools ‣ Export/Add Geometry Columns. Here, measurement is by default planimetric except if you choose the ellipsoidal measure.
Click the icon in the Attribute toolbar to begin measurements. The downward arrow near the icon helps you switch to the convenient tool to measure length, area or angle. The default unit used in the dialog is the one set in Project ‣ Project Properties ‣ General menu.
Nota
Configurazione dello strumento di misura
While measuring length or area, clicking the Configuration button at the bottom of the widget helps you define in menu Settings ‣ Options ‣ Map Tools the rubberband color, the precision of the measurements and the unit behavior. You can also choose your preferred measurement or angle units but keep in mind that those values are superseded in the current project by options made in Project ‣ Project Properties ‣ General menu.
Tutti gli strumenti di misurazione utilizzano le impostazioni di aggancio dal modulo di digitalizzazione (vedi la sezione Impostare la Tolleranza dello Snapping e il raggio di ricerca degli elementi). Quindi, se vuoi misurare esattamente lungo una geometria lineare o una geometria poligonale devi prima definire la tolleranza di aggancio e poi selezionare il vettore. In questo modo, quando vengono usati gli strumenti di misura, ogni click del mouse (all’interno della tolleranza definita) si aggancerà a quel punto del layer.
By default, Measure Line: QGIS measures real distances between given points according to a defined ellipsoid. 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.
Note that you can use the drop-down list near the total to interactively change the measurement units while measuring. This unit is kept for the widget until a new or another project is opened.
The Info section in the dialog explains how calculations are made according to CRS settings available.
Measure Area: Areas can also be measured. In the measure window, the accumulated area size appears. Right-click to stop drawing. The Info section is also available as well as the ability to switch between different area units.
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.
QGIS provides several tools to select features in the map canvas. Selection tools are available in View ‣ Select menu or in the Attributes toolbar.
Nota
Gli strumenti di selezione funzionano con il layer correntemente attivo.
To select one or several features with the mouse, you can use one of the following tools:
Nota
Except the Select Features by Polygon tool, these manual selection tools allow you to select feature(s) in the map canvas with a single click.
While using the Select Feature(s) tool, holding Shift or Ctrl toggles whether feature is selected (ie either adds to the current selection or remove from it).
For the other tools, different behaviors can be performed holding:
Shift: aggiunge geometrie alla selezione corrente
Ctrl: sottrae geometrie dalla selezione corrente
The other selection tools, also available from the Attribute table, perform a selection based on feature’s attribute or its selection state (note that attribute table and map canvas show the same information, so if you select one feature in attribute table, it will be selected in map canvas also):
For example, if you want to find regions that are boroughs from regions.shp of the QGIS sample data, you can use the Select features using an Expression icon. Then, you open the Fields and Values menu and choose the field that you want to query. Double-click the field ‘TYPE_2’ and also click [Load all unique values] in the right panel. From the list, choose and double-click ‘Borough’. In the Expression field, then you’d write the following query:
"TYPE_2" = 'Borough'
From the expression builder dialog, you can also use the Function list ‣ Recent (Selection) to make a selection that you used before. The dialog remembers the last 20 used expressions. See Espressioni chapter for more information and some example.
Suggerimento
Salva la selezione in un nuovo file
Users can save selected features into a New Temporary Scratch Layer or a New Vector Layer using Edit ‣ Copy Features and Edit ‣ Paste Features as in the wanted format.
This selection tool opens the layer’s feature form allowing the user to choose, for each field, which value to look for, if the search should be case sensitive, and the operation that should be used.
Alongside each field, there is a drop-down list with the operation options to control the search behaviour. The common options are:
Uguale a (=)
Senza valore (null)
INon è senza valore (not null)
For numeric and datetime fields, the additional options are:
Maggiore di (>)
Minore di (<)
Compreso fra (inclusivo)
For text fields, the additional options are:
Contiene
Non contiene
For the text options above, it is also possible to use the Case sensitive option.
After setting all search options, you can use the Select features button to select the matching features. The drop-down options are:
Seleziona elementi
Aggiungi alla selezione attuale
Filtra la selezione attuale
Rimuovi dalla selezione attuale
You can also clean all search options using the Reset form button.
Beside many options in the vector layer properties dialog or settings in the print composer, you can find a Data defined override icon. Thanks to expressions based on layer attributes or item settings, prebuild or custom functions and variables, this tool allows you to set dynamic value for the concerned parameter. When enabled, the value returned by this widget is applied to the parameter regardless its normal value (checkbox, textbox, slider...).
Clicking the Data defined override icon shows following entries:
Cancella per rimuovere l’impostazione.
Parameters that can be used with data-defined tools are:
Lo strumento Informazione elementi ti permette di interagire con la mappa e ottenere informazioni sulle caratteristiche delle geometrie in una finestra pop-up. Per avere informazione sulle geometrie usa:
QGIS offers two ways to identify features with the Identify Features tool:
Suggerimento
Filtra i layers su cui effettuare una query con lo strumento Identifica geometrie
Uncheck the Identifiable column in Project ‣ (or Settings ‣), Project Properties ‣ Identify layers menu in front of a layer to avoid it being queried when using the Identify Features in a mode other than Current Layer. This is a handy way to return features from only layers that are of interest for you.
If you click on feature(s), the Identify Results dialog will list information about the clicked feature(s). The default view is a tree view where the first item is the name of the layer and its children are its identified feature(s). Each feature is described by the name of a field along with its value. This field is the one set in Layer Properties ‣ Display. Then follows all the other information about the feature.
The Identify Results dialog can be customized to display custom fields, but by default it will display three kinds of information:
Azioni: le azioni possono essere aggiunte alle finestre delle identificazione delle geometrie. Le azioni si visualizzano facendo click sull’etichetta azione. Per impostazione predefinita, viene aggiunta una sola azione, vale a dire Modulo vista geometrica per effettuare modifiche. Puoi definire più azioni nella finestra di dialogo delle proprietà del layer (vedi Proprietà Azioni).
Attributi dei dati: questo è l’elenco dei campi e dei valori degli attributi per la geometria su cui è stato fatto click.
Nota
Links in feature’s attributes are clickable from the Identify Results panel and will open in your default web browser.
At the top of the window, you have seven icons:
At the bottom of the window, you have the Mode and View comboboxes. With the Mode combobox you can define from which layers features should be identified:
Nota
Identify tool configuration
You can configure the identify feature in Project ‣ Project Properties in the Identify layers tab. The table allows user to select layer(s) that can be used by this tool to identify features (column Identifiable). You can also put this layer in read-only mode with the checkbox in the last column.
La Visualizzazione può essere impostata a Albero, Tabella o Grafica. Le visualizzazioni ‘Tabella’ e ‘Grafica’ possono essere impostate solo per i layers raster.
The identify tool allows you to Auto open a form. If checked, each time a single feature is identified QGIS will open a form showing its attributes. This is a handy way to quickly edit a feature’s attributes.
Puoi trovare altre opzioni nel menu contestuale dell’elemento identificato. Per esempio, dal menu contestuale puoi:
Visualizzare modulo geometria
Zoomare alla geometria
Copiare elementi: copiare tutti gli elementi e gli attributi della geometria
Copiare un valore di un attributo: copiare solo il valore dell’attributo identificato
Copia attributi geometria: copia gli attributi della geometria
Cancellare risultati: verranno cancellati i risultati nella finestra
Cancellare evidenziati: verranno cancellate le geometrie evidenziate sulla mappa
Evidenziare tutto
Evidenziare vettore
Attivare un vettore: scegliere un vettore che deve essere attivato
Proprietà del vettore: aprire la finestra delle proprietà del vettore
Espandi tutto
Racchiudi tutto
The Text Annotation tool in the attribute toolbar provides the possibility to place formatted text in a balloon on the QGIS map canvas. Use the Text Annotation tool and click into the map canvas.
Double clicking on the item opens a dialog with various options. There is the text editor to enter the formatted text and other item settings. For instance, there is the choice of having the item placed on a map position (displayed by a marker symbol) or to have the item on a screen position (not related to the map). The item can be moved by map position (by dragging the map marker) or by moving only the balloon. The icons are part of the GIS theme, and they are used by default in the other themes, too.
The Move Annotation tool allows you to move the annotation on the map canvas.
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.
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.
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://youtu.be/0pDBuSbQ02o?t=2m25s from Tim Sutton for more information.
Nota
If you press Ctrl+T while an Annotation tool is active (move annotation, text annotation, form annotation), the visibility states of the items are inverted.
I segnalibri geospaziali ti permettono di memorizzare una posizione geografica alla quale potrai ritornare in un secondo momento. Per impostazione predefinita, i segnalibri vengono salvati sul computer, il che significa che sono disponibili per qualsiasi progetto attivato su tale computer. Se desideri memorizzare il segnalibro nel file di progetto (.qgs) puoi fare ciò selezionando la casella di controllo Nel Progetto.
Per creare un segnalibro:
Usa lo zoom o muovi la mappa all’estensione d’interesse.
Inserisci un nome descrittivo per il segnalibro (fino a 255 caratteri).
Seleziona il campo Progetto se desideri salvare il segnalibro nel file di progetto.
Premere Invio per aggiungere il segnalibro o fare clic altrove.
Nota che puoi avere più di un segnalibro con lo stesso nome.
To use or manage bookmarks, select the menu option View ‣ Show Bookmarks. The Spatial Bookmarks panel allows you to:
Zoom a un Segnalibro: seleziona il segnalibro desiderato e poi fai click su Zoom a un Segnalibro. Puoi fare lo zoom su un segnalibro anche facendo doppio click su di esso.
Cancellare un Segnalibro: seleziona il segnalibro e fai click su Elimina segnalibro. Conferma la tua scelta.
Sometimes, you’d like to keep in different projects a bunch of layers with the same style. You can either create a default style for these layers or embed them from another project to save you tons of work.
Layers e gruppi nidificati da un progetto esistente presenta alcuni vantaggi rispetto alla gestione dello stile:
If you want to embed content from other project files into your project, select Layer ‣ Embed Layers and Groups and:
Like any other layer, an embedded layer can be removed from the project by right-click on the layer and choose Remove.
Suggerimento
Cambiare la visualizzazione di un layer nidificato
It’s not possible to change rendering of an embedded layer, unless you make the changes in the original project file. However, right-click on a layer and select Duplicate creates a layer which is fully-featured and not dependent to the original project. You can then safely remove the linked layer.
The Decorations of QGIS include the Grid, the Copyright Label, the North Arrow and the Scale Bar. They are used to ‘decorate’ the map by adding cartographic elements.
Reticolo ti permette di aggiungere un reticolo e le coordinata alla mappa.
Copyright label adds a copyright label using the text you prefer to the map.
Scegli il posizionamento dell’etichetta nel menu a tendina Posizione .
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 places a simple north arrow on the map canvas. Currently, 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. You can refine the placement of the arrow by setting a Horizontal and/or Vertical Marging from (Canvas) Edge. These values can be a distance in Millimeter or Pixels or set as Percentage of the width or height of the map canvas.
Barra di scala aggiunge una semplice barra di scala alla mappa. Puoi controllare il posizionamento, lo stile, il colore e le dimensioni di etichettatura della barra.
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.
Per aggiungere una barra di scala:
Suggerimento
Settings of Decorations
When you save a .qgs project, any changes you have made to Grid, North Arrow, Scale Bar and Copyright will be saved in the project and restored the next time you load the project.
QGIS has facility to store/retrieve authentication credentials in a secure manner. Users can securely save credentials into authentication configurations, which are stored in a portable database, can be applied to server or database connections, and safely referenced by their ID tokens in project or settings files. For more information see Authentication System.
Una password master deve essere impostata durante l’inizializzazione del sistema di autenticazione e del relativo database portatile.
In QGIS, you can use variables to store useful recurrent values (e.g. the project’s title, or the user’s full name) that can be used in expressions. Variables can be defined at the application’s global level, project level, layer level, composition level, and composer’s item level. Just like CSS cascading rules, variables can be overwritten - e.g., a project level variable will overwrite any application’s global level variables set with the same name. You can use these variables to build text strings or other custom expressions using the @ character before the variable name. For example in composer creating a label with this content:
This map was made using QGIS [% @qgis_version %]. The project file for this
map is: [% @project_path %]
Visualizzerà l’etichetta in questo modo:
This map was made using QGIS 2.14. The project file for this map is:
/gis/qgis-user-conference-2015.qgs
Oltre alle variabili di sola lettura preimpostate, puoi definire tue variabili personalizzate per ciascuno dei layers sopra menzionati. Puoi gestire:
To differentiate from editable variables, read-only variable’s names and values are emphasized in italic. On the other hand, higher level variables overwritten by lower level ones are strike through.
Nota
You can read more about variables and find some examples in Nyall Dawson’s Exploring variables in QGIS 2.12, part 1, part 2 and part 3 blog posts.