Export Features

Export layers (filtered or unfiltered) to various formats using the EXPORTING tab.

Overview

The EXPORTING tab allows you to export layers from your QGIS project to standalone datasets for:

Sharing with colleagues or clients
Analysis in other software
Archiving snapshots of data
Publishing web maps
Reporting tabular data

Key Features:

Multi-selection of layers to export
Multiple output formats (GPKG, Shapefile, GeoJSON, etc.)
CRS transformation (re-projection)
Style export (QML, SLD, ArcGIS)
Batch mode (separate files per layer)
ZIP compression for delivery

Exporting Filtered Data

Layers can be exported with or without filters applied. If you've used the FILTERING tab to create filtered subsets, those filters are preserved during export. To export unfiltered data, remove filters first in the FILTERING tab.

EXPORTING Tab Components

Layer Selection

Select which layers to export from your QGIS project:

Check one or more layers to export

Features:

Multi-selection: Export multiple layers at once
Geometry indicators: Visual icons for point/line/polygon layers
Feature count: Shows current feature count (respects active filters)
Backend info: Displays data source (PostgreSQL⚡, Spatialite, OGR)

Format Selection

Choose the output format for exported data:

Dropdown with available export formats

Supported Formats

Format	Type	Best For	Max Size	Extension
GeoPackage	Vector	General use, large datasets	Unlimited	`.gpkg`
Shapefile	Vector	Legacy compatibility	2 GB	`.shp`
GeoJSON	Vector	Web mapping, APIs	~500 MB	`.geojson`
KML/KMZ	Vector	Google Earth, mobile	~100 MB	`.kml`, `.kmz`
CSV	Tabular	Spreadsheets, coordinates only	Unlimited	`.csv`
PostGIS	Database	Large datasets, enterprise	Unlimited	`(database)`
Spatialite	Database	Medium datasets, portable	~140 TB	`.sqlite`

CRS Transformation

Re-project layers during export to a different coordinate system:

QgsProjectionSelectionWidget for CRS selection

Features:

Choose any EPSG code or custom CRS
Common CRS presets (WGS84, Web Mercator, local projections)
On-the-fly reprojection during export
Preserves original layer (no modification)

Common CRS Transformations:

Original → Export CRS    | Use Case
-------------------------|----------------------------------
EPSG:4326 → EPSG:3857   | Web mapping (Leaflet, OpenLayers)
Local → EPSG:4326        | GPS compatibility
EPSG:4326 → UTM zone    | Accurate distance measurements
Various → Single CRS     | Harmonize multi-source data

Style Export

Export layer styling alongside data:

--> Choose style format: QML (QGIS), SLD (Standard), or ArcGIS

Available Formats:

QML (QGIS Style) - Full QGIS styling, preserves all features
SLD (Styled Layer Descriptor) - OGC standard, works in GeoServer, MapServer
ArcGIS - ArcGIS-compatible styling for Esri software

Style Export Behavior:

Format     | Includes                    | Compatible With
-----------|----------------------------|---------------------------
QML        | Full QGIS style tree       | QGIS only
SLD        | Basic symbology + labels   | GeoServer, MapServer, QGIS
ArcGIS     | Esri symbology             | ArcGIS Desktop, ArcGIS Pro

Output Options

Configure destination and delivery mode:

QgsFileWidget for folder selection

Checkboxes for Batch mode and ZIP compression

Options:

Output Folder: Choose destination directory
Batch Mode: Export each layer to a separate file (vs single file for all)
ZIP Compression: Automatically compress output for delivery

Batch Mode Comparison:

Normal Mode:
output_folder/
  └── export.gpkg (contains all layers)

Batch Mode:
output_folder/
  ├── layer1.gpkg
  ├── layer2.gpkg
  └── layer3.gpkg

Batch + ZIP:
output_folder/
  └── export_2024-12-09.zip
      ├── layer1.gpkg
      ├── layer2.gpkg
      └── layer3.gpkg

Export Workflow

Complete export process from EXPORTING tab:

Step-by-Step Example: Export After Filtering

Scenario: Export buildings within 200m of roads (from FILTERING tab) to GeoPackage

--> 1. FILTERING tab: Filter applied, 3,847 buildings found

--> 2. Switch to EXPORTING tab

--> 3. Select "buildings" layer to export (filtered subset will be exported)

--> 4. Configure: Format=GPKG, CRS=EPSG:3857 (Web Mercator), Styles=QML

All indicators active:

Has Layers to Export ✓
Has Datatype (GPKG) ✓
Has Projection (EPSG:3857) ✓
Has Styles (QML) ✓

--> 5. Select output folder + filename

--> 6. Click EXPORT button → Progress bar shows processing

--> 7. Success notification with output path: C:/exports/buildings_filtered.gpkg (3,847 features, 2.3 MB)

Result:

File created: buildings_filtered.gpkg
Style file: buildings_filtered.qml (in same folder)
CRS: EPSG:3857 (reprojected from original EPSG:4326)
Features: 3,847 (filtered subset only)

Format Details

GeoPackage (.gpkg)

Recommended format for most use cases.

Advantages:

✅ Single file (portable)
✅ Unlimited size
✅ Multiple layers per file
✅ Spatial indexes built-in
✅ Open standard (OGC)
✅ Fast performance
✅ Supports all geometry types

Limitations:

⚠️ Requires GDAL 2.0+ (standard in modern QGIS)

When to Use:

Default choice for most exports
Large datasets (>100k features)
Multi-layer exports
Long-term archiving

Export Example:

output_file = "/path/to/export.gpkg"
layer_name = "filtered_features"
# Single file, multiple layers possible

Shapefile (.shp)

Legacy format for backward compatibility.

Advantages:

✅ Universal compatibility
✅ Widely supported
✅ Simple structure

Limitations:

❌ 2 GB file size limit
❌ 10-character field name limit
❌ Limited data types
❌ Multiple files (.shp, .dbf, .shx, .prj)
❌ No mixed geometry types
⚠️ Encoding issues (non-ASCII characters)

When to Use:

Required by legacy software
Sharing with ArcGIS Desktop 9.x users
Simple, small datasets

Recommendations:

Use GeoPackage instead when possible
Keep feature count < 100k
Avoid long field names
Test encoding with non-ASCII characters

Export Example:

output_file = "/path/to/export.shp"
# Creates .shp, .dbf, .shx, .prj files

GeoJSON (.geojson)

Text-based format for web applications.

Advantages:

✅ Human-readable
✅ Web-friendly
✅ JavaScript native
✅ API integration
✅ Version control friendly

Limitations:

⚠️ Large file sizes (text format)
⚠️ Slower performance than binary formats
⚠️ No spatial indexes
⚠️ WGS84 (EPSG:4326) recommended

When to Use:

Web mapping (Leaflet, Mapbox)
REST APIs
Small to medium datasets (<10k features)
Git version control

Export Example:

output_file = "/path/to/export.geojson"
crs = "EPSG:4326"  # WGS84 recommended for web

KML/KMZ (.kml, .kmz)

Format for Google Earth and mobile apps.

Advantages:

✅ Google Earth compatibility
✅ KMZ includes styling and images
✅ Mobile app support
✅ Human-readable (KML)

Limitations:

❌ Limited attribute support
❌ Styling complexity
⚠️ Performance issues with large datasets
⚠️ WGS84 only (EPSG:4326)

When to Use:

Google Earth visualization
Mobile field apps
Stakeholder presentations
Public engagement

Export Example:

output_file = "/path/to/export.kmz"  # Compressed
# or
output_file = "/path/to/export.kml"  # Text

CSV (.csv)

Tabular format for coordinates and attributes.

Advantages:

✅ Universal spreadsheet compatibility
✅ Small file size
✅ Easy to edit
✅ Database import friendly

Limitations:

❌ No geometry (only X,Y coordinates for points)
❌ No spatial reference
❌ No styling
⚠️ Points only (no lines/polygons)

When to Use:

Point coordinates only
Excel/spreadsheet analysis
Attribute-only reports
Database imports

Export Example:

output_file = "/path/to/export.csv"
# Includes X, Y columns for point geometry
# GEOMETRY_AS: 'AS_XY' or 'AS_WKT'

PostGIS (PostgreSQL)

Export to PostgreSQL database with PostGIS extension.

Advantages:

✅ Best performance
✅ Unlimited size
✅ Multi-user access
✅ Spatial indexes
✅ Advanced querying
✅ Enterprise features

Limitations:

⚠️ Requires PostgreSQL + PostGIS
⚠️ Network setup needed
⚠️ More complex administration

When to Use:

Enterprise environments
Large datasets (>1M features)
Multi-user collaboration
Continuous updates
Integration with backend systems

Export Example:

connection = "postgresql://user:password@host:5432/database"
schema = "public"
table_name = "filtered_features"

Spatialite (.sqlite)

Lightweight database file.

Advantages:

✅ Single file
✅ Spatial indexes
✅ SQL queries
✅ Good performance
✅ No server needed

Limitations:

⚠️ Slower than PostGIS
⚠️ Single-writer limitation
⚠️ 140 TB theoretical max

When to Use:

Portable databases
Medium datasets (10k-1M features)
Offline work
Desktop applications

Export Example:

output_file = "/path/to/export.sqlite"
table_name = "filtered_features"

Export Options

Coordinate Reference System (CRS)

Choose the target CRS for your export:

# Keep original CRS
crs = layer.crs()

# Transform to WGS84 (web/GPS)
crs = "EPSG:4326"

# Transform to local projection
crs = "EPSG:32633"  # UTM Zone 33N

Common CRS Choices:

EPSG:4326 (WGS84) - Web maps, GPS, global
EPSG:3857 (Web Mercator) - Web tiles
EPSG:32xxx (UTM) - Local projected, metric
Original CRS - Maintain source projection

Field Selection

Export specific fields or all attributes:

# All fields
export_fields = None

# Selected fields only
export_fields = ['name', 'population', 'area', 'date']

# Exclude fields
exclude_fields = ['internal_id', 'temp_field']

Geometry Type

Control geometry export:

# Keep geometry (default)
geometry = True

# Attribute-only (no geometry)
geometry = False

# Simplify geometry (reduce size)
geometry = "simplified"
simplify_tolerance = 10  # meters

Encoding

Character encoding for text fields:

# UTF-8 (recommended, default)
encoding = "UTF-8"

# Latin-1 (Western Europe)
encoding = "ISO-8859-1"

# Windows-1252 (Windows default)
encoding = "CP1252"

Export Strategies

Large Dataset Export

For datasets > 100k features:

Recommendations:

Use GeoPackage or PostGIS - Binary formats
Enable spatial indexes - Faster subsequent access
Batch processing - Export in chunks if needed
Simplify geometry - Reduce vertex count if appropriate

Multi-Format Export

Export the same data to multiple formats:

# Export workflow
filter_applied = True

# Web version (GeoJSON)
export_geojson(crs="EPSG:4326", simplified=True)

# Desktop version (GeoPackage)
export_geopackage(crs=original_crs, full_precision=True)

# Spreadsheet version (CSV)
export_csv(coordinates="XY", attributes_only=False)

Incremental Exports

Export changes since last update:

# Filter by date
filter_expression = "last_modified >= '2024-01-01'"

# Export with timestamp
output_file = f"updates_{datetime.now().strftime('%Y%m%d')}.gpkg"

Practical Examples

Urban Planning Export

# Export filtered parcels for review
filter_expression = """
zone = 'commercial'
AND area > 5000
AND status = 'proposed'
"""

# Multiple formats for different stakeholders
export_geopackage("parcels_review.gpkg")  # GIS team
export_kml("parcels_review.kmz")  # Public presentation
export_csv("parcels_list.csv")  # Planning board

Environmental Monitoring

# Export monitoring sites with recent data
filter_expression = """
site_type = 'water_quality'
AND last_sample >= now() - interval '30 days'
AND parameter_count > 5
"""

# GeoJSON for web dashboard
export_geojson(
    output="monitoring_sites.geojson",
    crs="EPSG:4326",
    fields=['site_id', 'last_sample', 'status']
)

Emergency Response

# Export evacuation zones
filter_expression = """
intersects(
    $geometry,
    buffer(geometry(get_feature('hazard', 'status', 'active')), 2000)
)
AND occupancy > 0
"""

# KML for field teams
export_kml("evacuation_zones.kmz")

# GeoPackage for GIS analysis
export_geopackage("evacuation_analysis.gpkg")

Performance Optimization

Backend Comparison

Backend	Export Speed	Recommended
PostgreSQL	⚡⚡⚡⚡ Fastest	GeoPackage, PostGIS
Spatialite	⚡⚡⚡ Fast	GeoPackage, Spatialite
OGR	⚡⚡ Moderate	GeoPackage

Optimization Tips

Simplify Geometry

# Reduce vertex count
simplify_tolerance = 10  # meters

Select Necessary Fields

# Export only needed attributes
fields = ['id', 'name', 'status']

Use Appropriate Format

# Binary formats faster than text
GeoPackage > Shapefile > GeoJSON

Enable Spatial Indexes

# For GeoPackage/Spatialite
create_spatial_index = True

Troubleshooting

Export Fails

Common Issues:

File Locked
- Close applications using the file
- Check file permissions
Disk Space
- Verify available space
- Use compression (KMZ, GPKG)

Invalid Geometries

-- Filter invalid geometries before export
is_valid($geometry)

Encoding Issues
- Use UTF-8 encoding
- Test with sample features

Large File Size

Solutions:

Simplify geometry

simplify_tolerance = 10  # Reduce precision

Reduce attributes

fields = ['essential_field_1', 'essential_field_2']

Use compression

# KMZ instead of KML
# GPKG has internal compression

Split into tiles

# Export by region or grid
filter_expression = "region = 'north'"

Projection Issues

Solutions:

Verify source CRS

source_crs = layer.crs()
print(f"Source: {source_crs.authid()}")

Transform explicitly
```
target_crs = "EPSG:4326"
```

Check transformation accuracy

# Use appropriate transformation
# Especially for historic datums

Batch Export Examples

Multiple Filtered Layers

Export several layers with different configurations:

Scenario: Export 3 layers with different filters, formats, and CRS

Step 1 - Filter Layers (in FILTERING tab):

Layer 1 (parcels): zone = 'commercial'
Layer 2 (buildings): year_built > 2020
Layer 3 (roads): road_class = 'highway'

Step 2 - Configure Batch Export (in EXPORTING tab):

EXPORTING Tab Configuration:
- Layers selected: parcels, buildings, roads (all 3)
- Format: GeoPackage
- CRS: EPSG:3857 (Web Mercator)
- Styles: QML
- Output folder: C:/exports/
- Batch mode: ENABLED
- ZIP: ENABLED

Result:

C:/exports/export_2024-12-09.zip
  ├── parcels.gpkg (commercial zones, filtered)
  ├── parcels.qml
  ├── buildings.gpkg (recent buildings, filtered)
  ├── buildings.qml
  ├── roads.gpkg (highways, filtered)
  └── roads.qml

Benefits:

Single operation exports all layers
Each layer in separate file (batch mode)
All reprojected to Web Mercator
Styles preserved
Compressed for delivery

Overview​

EXPORTING Tab Components​

Layer Selection​

Format Selection​

Supported Formats​

CRS Transformation​

Style Export​

Output Options​

Export Workflow​

Step-by-Step Example: Export After Filtering​

Format Details​

GeoPackage (.gpkg)​

Shapefile (.shp)​

GeoJSON (.geojson)​

KML/KMZ (.kml, .kmz)​

CSV (.csv)​

PostGIS (PostgreSQL)​

Spatialite (.sqlite)​

Export Options​

Coordinate Reference System (CRS)​

Field Selection​

Geometry Type​

Encoding​

Export Strategies​

Large Dataset Export​

Multi-Format Export​

Incremental Exports​

Practical Examples​

Urban Planning Export​

Environmental Monitoring​

Emergency Response​

Performance Optimization​

Backend Comparison​

Optimization Tips​

Troubleshooting​

Export Fails​

Large File Size​

Projection Issues​

Batch Export Examples​

Multiple Filtered Layers​

Exporting Unfiltered Data​

Related Topics​

Next Steps​

Overview

EXPORTING Tab Components

Layer Selection

Format Selection

Supported Formats

CRS Transformation

Style Export

Output Options

Export Workflow

Step-by-Step Example: Export After Filtering

Format Details

GeoPackage (.gpkg)

Shapefile (.shp)

GeoJSON (.geojson)

KML/KMZ (.kml, .kmz)

CSV (.csv)

PostGIS (PostgreSQL)

Spatialite (.sqlite)

Export Options

Coordinate Reference System (CRS)

Field Selection

Geometry Type

Encoding

Export Strategies

Large Dataset Export

Multi-Format Export

Incremental Exports

Practical Examples

Urban Planning Export

Environmental Monitoring

Emergency Response

Performance Optimization

Backend Comparison

Optimization Tips

Troubleshooting

Export Fails

Large File Size

Projection Issues

Batch Export Examples

Multiple Filtered Layers

Exporting Unfiltered Data

Related Topics

Next Steps