KML (Keyhole Markup Language) is an XML-based format used to store geographic features and overlays, originally popularized by Google Earth. KMZ is a zipped version of KML that can bundle the KML with related resources such as icons or images.
Quick answer: KML is an XML map-overlay format used by Google Earth, while KMZ is a ZIP-compressed KML package that can include icons and images. Open either one in the online KML viewer or convert KML to GeoJSON.
To preview KML quickly, use the KML viewer: /open-kml-online/.
What KML contains
KML commonly includes:
- Placemarks (points, lines, polygons)
- Folders and feature grouping
- Styling information (colors, labels, icons)
- Descriptions and metadata
KMZ packages the same content into a single compressed file, which is easier to share.
When KML/KMZ is a good choice
Use KML/KMZ when:
- You need a format that works well in Google Earth
- You want to share map overlays with styling and organization
- Your workflow already produces KML outputs
Limitations
- KML is less convenient for modern web mapping toolchains than GeoJSON.
- Tooling can vary across platforms, especially for complex styling.
Convert KML to GeoJSON
GeoJSON is typically easier for web maps and APIs:
- Convert KML to GeoJSON: /kml-to-geojson/
- Open GeoJSON online: /open-geojson-online/
Related reading
- Comparison: /blog/kml-vs-geojson/