.
QGIS provides default keyboard shortcuts for many features. You can find them in section Главное меню. Additionally, the menu option Settings ‣ Configure Shortcuts.. allows you to change the default keyboard shortcuts and to add new keyboard shortcuts to QGIS features.
Figure Shortcuts 1:
Configuration is very simple. Just select a feature from the list and click on [Change], [Set none] or [Set default]. Once you have finished your configuration, you can save it as an XML file and load it to another QGIS installation.
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.
By default, QGIS renders all visible layers whenever the map canvas is refreshed. The events that trigger a refresh of the map canvas include:
добавление слоя
панорамирование или масштабирование
включение или отключение слоя/слоёв в легенде
QGIS allows you to control the rendering process in a number of ways.
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.
Map rendering can be controlled in the various ways, as described below.
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 Рендеринг. Examples of when you might want to suspend rendering include:
комбинации вышеперечисленного
Включение флажка Отрисовка активирует отрисовку и немедленно обновляет содержимое карты.
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.
Чтобы остановить отрисовку карты нажмите ESC. Обновление карты будет отменено и она останется частично отрисованной. Между нажатием клавиши ESC и остановкой отрисовки может пройти некоторое время.
Примечание
It is currently not possible to stop rendering — this was disabled in the Qt4 port because of User Interface (UI) problems and crashes.
You can set an option to update the map display as features are drawn. By default, QGIS does not display any features for a layer until the entire layer has been rendered. To update the display as features are read from the datastore, choose menu option Settings ‣ Options and click on the Rendering tab. Set the feature count to an appropriate value to update the display during rendering. Setting a value of 0 disables update during drawing (this is the default). Setting a value too low will result in poor performance, as the map canvas is continually updated during the reading of the features. A suggested value to start with is 500.
To influence the rendering quality of the map, you have two options. Choose menu option Settings ‣ Options, click on the Rendering tab and select or deselect following checkboxes:
There are two settings that allow you to improve rendering speed. Open the QGIS options dialog using Settings ‣ Options, go to the Rendering tab and select or deselect the following checkboxes:
Measuring works within projected coordinate systems (e.g., UTM) and unprojected data. If the loaded map is defined with a geographic coordinate system (latitude/longitude), the results from line or area measurements will be incorrect. To fix this, you need to set an appropriate map coordinate system (see section Работа с проекциями). All measuring modules also use the snapping settings from the digitizing module. This is useful, if you want to measure along lines or areas in vector layers.
To select a measuring tool, click on and select the tool you want to use.
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. Note that you can interactively change the measurement units in the measurement dialog. It overrides the Preferred measurement units in the options. There is an info section in the dialog that shows which CRS settings are being used during measurement calculations.
Figure Measure 1:
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 Настройка порога прилипания и радиуса поиска). 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 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:
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:
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.
The Identify tool allows you to interact with the map canvas and get information on features in a pop-up window. To identify features, use View ‣ Identify features or press Ctrl + Shift + I, or click on the Identify features icon in the toolbar.
If you click on several features, the Identify results dialog will list information about all the selected features. The first item is the number of the layer in the list of results, followed by the layer name. Then, its first child will be the name of a field with its value. The first field is the one selected in Properties ‣ Display. Finally, all information about the feature is displayed.
This window can be customized to display custom fields, but by default it will display three kinds of information:
Figure Identify 1:
At the top of the window, you have five icons:
At the bottom of the window, you have the Mode and View comboboxes. With the Mode combobox you can define the identify mode: ‘Current layer’, ‘Top down, stop at first’, ‘Top down’ and ‘Layer selection’. The View can be set as ‘Tree’, ‘Table’ and ‘Graph’.
The identify tool allows you to auto open a form. In this mode you can change the feautures attributes.
Other functions can be found in the context menu of the identified item. For example, from the context menu you can:
Увеличить до объекта
Подсветить всё
Подсветить всё в слое
Развернуть всё
Свернуть всё
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.
Grid allows you to add a coordinate grid and coordinate annotations to the map canvas.
Figure Decorations 1:
Выберите пункт меню Вид ‣ Оформление ‣ Сетка. Откроется диалог (см. figure_decorations_1).
Активируйте флажок Аннотация и настройте отображение подписей координат.
Copyright label adds a copyright label using the text you prefer to the map.
Figure Decorations 2:
Выберите пункт меню Вид ‣ Оформление ‣ Знак авторского права. Откроется диалог (см. figure_decorations_2).
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. 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:
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:
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.
Для добавления масштабной линейки:
Совет
Настройки оформления
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.
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.
Figure annotation 1:
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://www.youtube.com/watch?v=0pDBuSbQ02o from Tim Sutton for more information.
Figure annotation 2:
Примечание
Нажатие Ctrl+T при активном инструменте аннотаций (переместить аннотацию, текстовая аннотация, диалоговая аннотация), инвертирует видимость существующих аннотаций.
Spatial Bookmarks allow you to “bookmark” a geographic location and return to it later.
Для создания закладки:
Масштабируйте или панорамируйте карту до интересующей вас территории.
введите описательное имя для закладки (до 255 символов)
Помните, что можно иметь множество закладок с одинаковыми названиями.
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.
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.
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].
To share or transfer your bookmarks between computers you can use the Share pull down menu in the Geospatial Bookmarks dialog.
If you want to embed content from other project files into your project, you can choose Layer ‣ Embed Layers and Groups.
The following dialog allows you to embed layers from other projects. Here is a small example:
Figure Nesting 1:
While the embedded layers are editable, you can’t change their properties like style and labeling.