Creating Custom Garmin Maps (KMZ)

What Garmin Custom Maps Are

Garmin Custom Maps are georeferenced raster maps stored in KMZ format, compatible with many Garmin outdoor GPS devices.

The KMZ file contains the map images and their related geographic coordinates, allowing the device to correctly display the cartography on the terrain.

Preparing the Raster Map

Before creating a KMZ map, you must have a properly calibrated map available.

The scan quality, the accuracy of the georeferencing, and the readability of the cartography directly affect the final result on the GPS device.

Exporting the Map in KMZ Format

The software generally divides the map into raster tiles compatible with Garmin limits and automatically generates the final KMZ file.

To improve device performance, it is recommended to optimize image size, resolution, and the number of exported tiles.

Transferring the Map to the Garmin GPS

The KMZ file must be copied into the dedicated folder of the Garmin device, usually named "CustomMaps".

After the transfer, the map will be available directly on the GPS device and can be used together with waypoints, GPX tracks, and other installed maps.

Limitations of Garmin KMZ Maps

Garmin devices impose limits on the number of raster tiles, image size, and the total amount of loadable data.

For this reason, it is often necessary to reduce map resolution or split large cartographic areas into multiple separate files.

Creating Garmin Maps with OkMap

OkMap allows you to easily export georeferenced maps in Garmin KMZ format.

The software also allows management of calibration, raster optimization, and transfer to compatible outdoor GPS devices.