Frequently Asked Questions

The maps from OpenMapChest work with the following Garmin devices:

• Nuvi series
• Zumo series - including derivatives such as the BMW devices
• eTrex, Oregon, Dakota, Colorado, Montana, Colorado and GPSMAP handhelds
• StreetPilot if the device has an SD Card slot
• Honda Goldwing GL1800 1st-gen Navi (CF card) - map needs to be called gmapsupp.img and it must be smaller than 2GB
• Zumo 660 - map needs to be called gmapsupp.img
• There are reports of these maps working on Kenwood in-car map systems (e.g. DNX521DAB) but the update procedure is a bit involved. This forum post should point you in the right direction but I'm not able to provide support for this.

Other Garmin devices with an SD Card slot should work but I haven't tested them personally. Let me know if the maps work on a device not listed here. For older devices, the map needs to be called gmapsupp.img and it must be smaller than 2GB. See details in the instructions section about older device

The maps on this site use the older Garmin format, the so called legacy or non-NT format. The maps work well and are very usable, but some features that were added to the newer NT format are not available, notably:

• No displayed speed limits: Speed limits are not displayed on screen while driving, however, speed limits are used for calculating the best route.
• No Junction View (JCV): These maps do not include Junction View images which means images of major highways, exits, and merge lanes do not appear while driving.
• No Lane Assist: These maps do not include Lane Assist which means icons of the lanes and which lane to use does not appear in the upper left corner when approaching a turn.
• Larger maps: The non-NT map format is less efficient than the newer NT format which means these maps are larger than Garmin's official maps.

Hi 👋, I'm Ben Konrath.

I run OpenMapChest as a side-project. I love maps and created OpenMapChest to share the maps I make with other people. I hope you find them useful.

I spend my time on this project improving the maps and the map-making process, helping users who encounter problems, and improving the OpenMapChest website.

The maps are created using map data provided by the OpenStreetMap project, a user-editable map of the world. Extra address data is added for some maps from OpenAddresses (Canada, USA, Mexico, Australia, New Zealand) and the United States Census Bureau TIGER dataset (USA).

Like all maps, the maps from OpenMapChest will have some errors. The advantage of using an OpenStreetMap based map is that you can fix any problems you find directly in OpenStreetMap and be using your fixes within a week. That's not possible with Garmin's official maps.

Want to make a change to the map data? Check out the OpenStreetMap beginners' guide to get started.

Most of the maps are updated weekly so that everyone can benefit from the fixes and updates in the OpenStreetMap data without too much delay.

The map build script is usually started Friday night / Saturday morning and takes about 4 days to complete - yes, it's a lot of data to process! You can expect an updated version of your favorite map to appear on the site sometime between Saturday and Tuesday.

You probably don't need to update weekly (but you can if you want). I personally update my maps once every couple of months unless there's a specific fix I want to start using right away.

The maps are created using the mkgmap map compiler. You can create your own maps by following the mkgmap map creation guide.

You need to fully restart your Garmin device after updating to a new version of the map. This ensures that the device will properly read the new map without having any of the previous map data saved in its memory. The OpenMapChest maps should remain enabled when the device restarts.

How do you do this? Press on the power button for 4 seconds and you will be prompted to turn off your device. Once it's off, just press the power button again to turn it on.

When you update to a newer version of a map, you may need to manually recalculate your routes in BaseCamp. This is required when the road data has changed which causes issues importing previously saved GPX routes into Garmin GPS devices. This is only required if the GPX route is not importing correctly.

How do you do this? Open BaseCamp with the target map loaded, right click on the problematic route and select "Recalculate". A new route will be generated using the updated road network and it should now import into the GPS device without problems.

In the Canada map, address search in available is most major cities, but in some smaller towns the addresses are missing.

This can be because the address data for the smaller towns is missing in OpenStreetMap and OpenAddresses, or the boundary data for these towns and villages is incomplete.

I'm slowly improving things, and hopefully address search will be fully available in the Canada map in the future.