Garmin Custom Maps KMZ (Tiled JPEG Overlay)
Open BetaGarmin Custom Maps KMZ is the official (since 2010) way to load your own raster map onto Garmin Oregon, Colorado, Dakota, GPSMAP, Montana and etrex navigators without building a vector IMG. Inside is an ordinary ZIP with doc.kml, where each JPEG tile is described by a GroundOverlay section tied to four corners. On osm2cdr we render the chosen area via QGIS into a grid of 1024×1024 JPEG tiles and assemble the finished .kmz entirely on the server. To be honest: it is a flat raster layer at a single detail level — no routing or search, but ready in a minute. We honour Garmin's hardware limit: up to 100 overlays per file.
Key Features
About Garmin Custom Maps KMZ Format
Custom Maps is Garmin's official mechanism since 2010: the device reads an ordinary KMZ in which a raster image is tied to the ground by a GroundOverlay section. The format is the same as Google Earth's, so one and the same file opens both on a computer and on a navigator.
This path is chosen for its simplicity. Building an IMG vector map is harder and slower, whereas here a rendered picture is enough: a weekend route, a nature reserve map, a race course diagram, a city walk plan.
The area is rendered into 1024x1024 JPEG tiles — that is the ceiling in Garmin's specification — each described by its own GroundOverlay with corner coordinates, and everything is packed into a ZIP together with doc.kml. The hardware limit is respected: no more than 100 overlays per file.
The limitations are the usual ones for a raster underlay: one level of detail, no routing and no address search. The devices themselves also have an overall cap on the number of custom tiles, which depends on the model — if the layer does not appear, reduce the area.
What Program Opens Garmin Custom Maps KMZ Files
The following programs and applications can open, edit, and work with Garmin Custom Maps KMZ (Tiled JPEG Overlay) (.kmz) files exported from OSM2CDR:
Format specifications
- Proprietary format
- 2D only
- Lossy compression
- No attributes
- Output: 1 file
- A Garmin Custom Maps KMZ (ZIP of doc.kml + JPEG GroundOverlays): 1024x1024 tiles at quality 85, a single detail level, up to 100 overlays per the hardware limit.
Who Uses Garmin Custom Maps KMZ Maps
How to Export Garmin Custom Maps KMZ
How to Open After Export
- A Garmin device — connect over USB and copy the .kmz into the Garmin/CustomMaps/ folder in internal memory or on the microSD; the layer is enabled in the map settings.
- Google Earth Pro (free) — open the file with a double click and make sure the map lies flat and in the right place, before the trip.
- Garmin BaseCamp — viewing the map on a computer together with tracks and waypoints.
- Check the file size — if it is over a hundred megabytes, the device will pan the map slowly: reduce the area or the detail level.
- If the layer did not appear — check the path (it must be Garmin/CustomMaps), restart the device and remove any extra custom maps: the model has an overall tile cap.
Popular maps in Garmin Custom Maps KMZ
Get Garmin Custom Maps KMZ (Tiled JPEG Overlay) map exports
Download professional Garmin Custom Maps KMZ maps from OpenStreetMap. Instant generation, any area.