Working with Project Files¶
The state of your QGIS session is called a project. QGIS works on one project at a time. Any settings can be project-specific or an application-wide default for new projects (see section 옵션). QGIS can save the state of your workspace into a project file using the menu options or .
If the project you loaded has been modified in the meantime, by default, QGIS will ask you if you want to overwrite the changes. This behavior is controlled by the Prompt to save project and data source changes when required setting under menu.
At startup, a list of recently opened projects is displayed, including screenshots, names and file paths (for up to ten projects). This is a handy quick way to access recently used projects. Double-click an entry in this list to open the corresponding project. If you instead want to create a new project, just add any layer and the list disappears, giving way to the map canvas.
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. This means that it is possible to edit the file outside of QGIS if you know what you are doing. The file format has been updated several times compared with earlier QGIS versions. Project files from older QGIS versions may not work properly any more.
Whenever you save a
.qgs project in QGIS, a backup of the project file is created with the
.qgs~ and stored in the same directory as the project file.
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 (
.qgd) for auxiliary data.
You can get to these files by unzipping.
A zipped project may be particularly useful with the Auxiliary Storage Properties mechanism in order to embed the underlying database.
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 (currently just PostgreSQL). Clicking the action will open a dialog to pick a PostgreSQL connection name, schema name and project.
Projects stored in PostgreSQL can be also loaded from the QGIS browser panel (the entries are located within the schema they are stored in), either by double-clicking them or by dragging them to the map canvas.
There are several ways to generate output from your QGIS session. We have already discussed saving as a project file in Introducing QGIS projects. Other ways to produce output files are:
Creating images: opens a file dialog where you select the name, path and type of image (PNG, JPG and many other formats). This will also create a world file (with extension
JPGW) that is saved in the same folder as your image. This world file is used to georeference the image.
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
Exporting to PDF files: Extent) of the map to be exported, the Scale, Resolution, Output width (pixels) and Output height (pixels). You can also choose to Draw active decorations and Draw annotations, as well as Rasterize map.opens a dialog where you can define the part (
Designing print maps: opens a dialog where you can layout and print the current map canvas (see section Laying out the maps).