Convert KMZ Files to KML for Google Earth and GIS

What are KMZ and KML?

KML (Keyhole Markup Language) is an XML-based format that describes geographic features — placemarks, lines, polygons, styles, and overlays. It is human-readable and editable with a text editor.
KMZ is a compressed (zipped) version of a KML file. A KMZ file typically contains a KML plus embedded resources such as images, icons, or models. The KMZ extension helps package everything together for easier sharing and smaller file size.

Why convert KMZ to KML?

Editability: KML is plain XML, so it’s easier to inspect and edit directly when debugging or customizing styles.
Compatibility: Some GIS tools and scripts require KML input rather than compressed KMZ.
Automation: Automated pipelines or version-control systems handle plain-text KML files better than binary/compressed KMZ.
Troubleshooting: Extracting the KML from a KMZ lets you inspect embedded resources or fix malformed XML.

When you might keep KMZ instead

You want a single portable file containing images and icons.
You need smaller file size for sharing by email or upload.
Recipients expect a ready-to-open file for Google Earth.

Methods to convert KMZ to KML

Below are straightforward methods sorted by ease and typical use cases.

1) Manual unzip (fast, no extra tools)

A KMZ is a ZIP archive. You can rename and extract it or use unzip tools.

Change file extension from .kmz to .zip (optional).
Right-click → Extract (Windows Explorer, macOS Finder) or use command line:
- Windows (PowerShell): Expand-Archive -Path “file.kmz” -DestinationPath “outfolder”
- macOS / Linux: unzip file.kmz -d outfolder
Inside the extracted folder you’ll usually find a doc.kml or a file with .kml extension. That is your KML.

Example (macOS / Linux):

unzip mymap.kmz -d mymap_extracted # The extracted folder contains doc.kml (rename if needed)

2) Google Earth (desktop)

Open Google Earth Pro.
File → Open → select the .kmz.
Right-click the imported layer in “Places” → Save Place As… → choose “KML” as the format.

This is convenient for users who want a GUI and to inspect visual results.

3) GIS software (QGIS, ArcGIS)

QGIS:
- Layer → Add Layer → Add Vector Layer → select your .kmz.
- Right-click the imported layer → Export → Save Features As… → select “KML” and save.
ArcGIS:
- Use “KML To Layer” or import, then export to KML via conversion tools.

These options are best when working with attribute tables, coordinate reference systems (CRS), or batch conversions.

4) Command-line tools (GDAL/OGR)

GDAL/OGR is powerful for scripted or batch conversions.

Example using ogr2ogr:

ogr2ogr -f KML output.kml input.kmz

For batch directories:

for f in *.kmz; do ogr2ogr -f KML "${f%.kmz}.kml" "$f"; done

GDAL handles coordinate transformations and can extract thematic attributes as needed.

5) Online converters

Many websites convert KMZ to KML quickly. Use them for occasional, small files if privacy is not a concern. Verify site reputation before uploading sensitive data.

Handling embedded resources (icons, images, 3D models)

When a KMZ contains images or 3D models, extracting the KMZ will reveal folders with those assets. If you convert using tools that only extract the KML text, you may lose local references to those files. To preserve them:

Use manual unzip to keep folder structure intact.
When using Google Earth or GIS export, check options to include media or packaged resources.
If you must edit KML paths, update the tags to point to the correct relative path or host assets on a web server and use absolute URLs.

Coordinate systems and projection considerations

KML/KMZ use WGS84 geographic coordinates (EPSG:4326 — latitude/longitude). When converting from other GIS formats, ensure you reproject to WGS84 to avoid misplaced features. GDAL/ogr2ogr and GIS desktop tools provide reprojection options; e.g.:

ogr2ogr -f KML -t_srs EPSG:4326 output.kml input.shp

Batch conversion workflows

Use ogr2ogr in shell scripts for thousands of files.
In QGIS, use the Processing Toolbox > Batch Convert to run multiple conversions with a GUI.
For reproducible pipelines, include a step that validates produced KML (simple check: parse as XML and confirm presence of root).

Troubleshooting common issues

No doc.kml after extracting: the KML might be nested in a subfolder; search extracted contents for *.kml.
Broken icons/images: ensure resource files are in the same relative paths as referenced in the KML, or edit tags.
Large files: split into multiple KMLs or simplify geometries (use ogr2ogr -simplify or QGIS’s Simplify Geometries).
Encoding problems: ensure text files are UTF-8. Use an editor that can re-save as UTF-8 if needed.

Example: Convert and edit a KMZ, step-by-step

Make a copy of your mymap.kmz.
unzip mymap.kmz -d mymap_extracted
Open mymap_extracted/doc.kml in a text editor. Edit placemark names or style definitions.
Save as edited_map.kml.
If you need to repackage with images, create a new folder, place edited_map.kml and asset files (icons/) and zip them:
```
cd new_package_folder zip -r ../edited_map.kmz * 
```
Open edited_map.kmz in Google Earth to verify.

Best practices

Keep original KMZ backups before editing.
Use relative paths for embedded assets when you plan to zip/unzip.
Reproject source data to WGS84 before converting to KML/KMZ.
For version control, store KML (text) rather than KMZ (binary).
Strip large unnecessary media from KMZ when performance matters.

Summary

KML is editable XML; KMZ is its zipped package with resources.
Convert when you need editability, compatibility with text-based workflows, or troubleshooting access.
Use simple unzip, Google Earth, GIS software, or ogr2ogr depending on your needs.
Preserve resource paths when dealing with images/3D models and ensure data uses WGS84.

If you want, I can:

Provide a ready-made shell script to batch-convert a folder of KMZ files to KML, or
Walk through converting a specific KMZ you have (describe its contents).