If the project has been modified the
* symbol will appear in the title bar
and QGIS will, by default, ask you if you would like to save the changes.
This behavior is controlled by the
Prompt to save project and data source changes when required
setting under .
At startup, a list of Project Templates and Recent Projects are displayed, including screenshots, names and file paths (for up to ten projects). The Recent Projects list is handy to access recently used projects. Double-click an entry to open the project or project template. You can also add a layer to create a new project automatically. The lists will then disappear, giving way to the map canvas.
When you open a fresh project, the title bar will show
Untitled Project until you
The information saved in a project file includes:
Which layers can be queried
Layer properties, including symbolization and styles
Projection for the map view
Last viewed extent
Print layout elements with settings
Print layout atlas settings
Project default styles
QGIS Server settings from the OWS settings tab in the Project properties
Queries stored in the DB Manager
The project file is saved in XML format (see QGS/QGZ - QGIS工程文件格式). This means that it is possible to edit the file outside of QGIS if you know what you are doing. The project file format has been updated several times. Project files from older QGIS versions may not work properly any more.
Whenever you save a
.qgs project file in QGIS, a backup of the
file is created in the same directory as the project file, with the
The extension for QGIS projects is
.qgs but when saving from QGIS,
the default is to save using a compressed format with the
.qgs file is embedded in the
.qgz file (a zip archive),
together with its associated sqlite database (
You can get to these files by unzipping the
The Auxiliary Storage Properties mechanism makes a zipped project particularly useful, since it embeds auxiliary data.
Projects can also be saved/loaded to/from a PostgreSQL database using the following Project menu items:
Both menu items have a sub-menu with a list of extra project storage implementations (PostgreSQL and GeoPackage). Clicking the action will open a dialog to pick a GeoPackage connection and project or a PostgreSQL connection, schema and project.
Projects stored in Geopackage or PostgreSQL can also be loaded through the QGIS browser panel, either by double-clicking them or by dragging them to the map canvas.
When opening a project, QGIS may fail to reach some data sources due to unavailable service/database, or to a renamed or moved file. QGIS then opens the Handle Unavailable Layers dialog, referencing the unfound layers. You can:
Double-click in the Datasource field, adjust the path of each layer and click Apply changes;
Select a row, press Browse to indicate the correct location and click Apply changes;
Press Auto-Find to browse the folders and try to automatically fix all or selected broken path(s). Be aware that the browsing may take some time.
Ignore the message and open your project with the broken path(s) by clicking Keep Unavailable Layers. Your layer is then displayed in the Layers panel, but without any data until you fix the path using the Unavailable layer! icon next to it in the Layers panel, or Repair Data Source... in the layer contextual menu.
With the Repair Data Source... tool, once a layer path has been fixed, QGIS scans through all other broken paths and tries to auto-fix those that have the same broken file path.
There are several ways to generate output from your QGIS session. We have already discussed saving as a project file in 介绍QGIS项目. Other ways to produce output files are:
Creating images: outputs the map canvas rendering to an image format (PNG, JPG, TIFF...) at custom scale, resolution, size, ... Georeferencing the image is possible. See Exporting the map view for more details.
Exporting to PDF files: Exporting the map view for more details.outputs the map canvas rendering to PDF at custom scale, resolution, and with some advanced settings (simplification, georeferencing, ...). See
Exporting to DXF files: Creating new DXF files).opens a dialog where you can define the 'Symbology mode', the 'Symbology scale' and vector layers you want to export to DXF. Through the 'Symbology mode', symbols from the original QGIS Symbology can be exported with high fidelity (see section
Designing maps: opens a dialog where you can layout and print the current map canvas (see section Laying out the maps).