Convert PNG to KML

Understanding PNG and KML file formats

PNG (Portable Network Graphics) is a popular raster image format known for its lossless compression and support for transparency. It is widely used for web graphics, digital photos, and images requiring high quality and clear backgrounds.

KML (Keyhole Markup Language) is an XML-based file format used to display geographic data in mapping applications such as Google Earth and Google Maps. KML files can contain points, lines, polygons, and images, allowing users to visualize spatial information on a map.

Why convert PNG to KML?

Converting a PNG image to a KML file is useful when you want to overlay an image (such as a map, diagram, or satellite photo) onto a geographic location in mapping software. This process is called image georeferencing, and it enables you to align the PNG image with real-world coordinates for visualization in applications like Google Earth.

How to convert PNG to KML

Direct conversion from PNG to KML is not possible because PNG is an image format and KML is a geographic markup format. The process involves georeferencing the PNG image and then exporting it as a KML overlay. Here are the general steps:

1. Use a GIS (Geographic Information System) software such as QGIS (free and open-source) or Google Earth Pro.
2. Import your PNG image into the software.
3. Georeference the image by assigning real-world coordinates to specific points on the PNG.
4. Export the georeferenced image as a KML file with a ground overlay.

Recommended software for PNG to KML conversion

• QGIS (Windows, macOS, Linux):
  • Load your PNG image using Layer → Add Layer → Add Raster Layer.
  • Open the Georeferencer tool via Raster → Georeferencer.
  • Assign control points and set the coordinate reference system.
  • Export the georeferenced image as a KML overlay using Project → Import/Export → Export Map to KML.
• Google Earth Pro (Windows, macOS):
  • Open Google Earth Pro and go to Add → Image Overlay.
  • Browse and select your PNG file.
  • Adjust the image location and size to fit the map.
  • Save the overlay as a KML file using File → Save → Save Place As.

Online converters

There are limited online tools for direct PNG to KML conversion due to the need for georeferencing. However, some web-based GIS platforms like MapTiler or GeoConverter offer image georeferencing and KML export features, but manual adjustment is usually required.

Summary

To convert a PNG image to a KML file, you must georeference the image using GIS software and export it as a KML overlay. QGIS and Google Earth Pro are the best tools for this process, offering precise control and compatibility with mapping applications.