QGZ (Quantum GIS Zipped Project)

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Introduction

QGZ files are compressed file formats used to save projects in QGIS (Quantum GIS) software. QGIS is an open source geographic information system (GIS) software that is widely used for visualization, editing, and analysis of spatial data. The QGZ format essentially compresses the configuration files (.qgs files in XML format) of the QGIS project into a single file for easy storage and transmission. Unlike QGS files, the QGZ format has better storage management capabilities and is particularly suitable for handling complex projects.

Data Format

File Content

A QGZ file is essentially a ZIP compressed package that contains the core configuration files of the QGIS project:

project.qgs: The main project file stores all configurations of the project in XML format, including layer styles, coordinate reference systems, spatial bookmarks, layouts, and other metadata information.
Other resource files that may be included: such as external data source references, icons, symbols, and cache files.

File extension

The extension is .qgz, which corresponds to the uncompressed QGS file (.qgs).

Structural features

QGZ files are automatically decompressed when opened for reading and editing by QGIS software. When saving a project, QGIS will recompress and save it in QGZ format.
QGZ files do not directly store actual spatial data, but reference external data sources (such as Shapefile, GeoTIFF, PostGIS database, etc.) through paths.

Pros

1. Easy to store and transfer: The QGZ format compresses project files into a single file, which is suitable for storage, sharing and backup, especially for large projects.

2. Automatic decompression and recompression: QGIS software can handle QGZ files seamlessly, and users do not need to manually decompress them, which improves the user experience.

3. Readability and editability: The core configuration file of the project (project.qgs) is still in XML format, which is easy to parse and manually edit, and is convenient for problem diagnosis and scripting.

4. Data integrity: Compressing and storing project files can reduce the risk of file corruption while maintaining the integrity of project settings.

Cons

1. Does not contain actual data: The QGZ file itself only saves the project configuration, not the spatial data, and relies on the external data source path. If the data path changes, the project may not load correctly.

2. Limited storage efficiency: If the project is large, the compressed QGZ file may still be large, especially when the project references a large amount of high-resolution raster data.

3. Software dependency: QGZ files are mainly read and edited by QGIS and cannot be opened directly in other GIS software. They need to be decompressed and converted first.

Application Scenario

The QGZ file format is widely used in various GIS project management scenarios, especially when there is a need to share project configurations, back up project files, and transfer across platforms. QGZ provides an efficient project storage solution for individuals or teams performing spatial analysis, mapping, and data visualization in QGIS. Researchers can use the QGZ format to save geographic data analysis processes and style settings to ensure the reproducibility and integrity of the project. In collaborative work, team members can reproduce project configurations by sharing QGZ files to achieve consistent geographic data presentation and layout.