Introduction: Adding Free OpenStreetMaps to Your Garmin Oregon 450 GPS

The Garmin Oregon series of handheld GPS units are very popular amongst
Geocachers. Recently I was asked how to install a microSD card into one and also how to load GPX files and additional maps.

This short Instructable will guide users through the process of downloading some high quality free maps into a Garmin Oregon 450.

You should have installed a microSD card into the Garmin before proceeding. If you are not sure how to do this, please visit my article Installing a microSD Card in a Garmin Oregon 450.

Thank you to Helen Edley of for the Mac screen shots and all the editing of this article!

Step 1: Why OpenStreetMap?

OpenStreetMap is similar to Wikipedia, but for maps - it allows the internet community to add, update and correct the content. Why is this important? Well, if you live in an area that doesn't have much map detail in say Google Maps or Topo Canada, then you can easily use your GPS unit to add all the trails in your local park or favorite hiking spot. In fact, one of the most valuable features of OpenStreetMap is that there are thousands of trails and green spaces on the map already added by people just like you!

No longer do we have to rely on corporations, cartographers, or national
institutions to generation mapping data when they get around to it - you can use your own GPS to add information to a map. And chances are people in your area have already done some of it for you. Future Instructables will demonstrate how you can contribute (if you would like) to this resource by updating the map yourself using your GPS.

Above are two examples - the first is an OpenStreetMap loaded on my GPS unit that shows not only the roads, but the trails. It clearly shows a Geocache on a trail through the area. The second is Garmin's "Topo Canada" which is similar to "There be Dragons Here" with a cache somewhere in it. I would be left to discover a trail in the area by "Hit and miss".

The maps for most of the world can be downloaded for free and loaded onto your Garmin GPS.

Step 2: Make Sure You Have a MicroSD Card Installed in Your Garmin Oregon

To load a map into a Garmin Oregon, you must have a microSD card installed. If you are not sure if you do, remove the batteries and check for a small (usually black) card installed under the metal flap in the Battery bay (See Photo).

If you need help installing a new one, please see my article Installing a microSD Card in a Garmin Oregon 450.

Step 3: Overview of the Process - Four Easy Steps

The process is quick and easy - usually the slowest part is waiting for the file to finish copying!

  1. Download the .ZIP file of the region you are interested in.
  2. UnZip the File.
  3. Copy the resulting .IMG file to your microSD card.
  4. Enable the map.

Step 4: Download the OpenStreetMap .ZIP File

Download the OpenStreetMap .ZIP file for the region you want. For this example I will use the Canada map.

On the Canada page, there is a link near the bottom called "Direct Download" that when clicked, opens a dialog to save the file to your hard drive. In my case the file is called "Canada Garmin Map" but the name of the file will change based on region and the last update date.

Depending on your operating system, you may have a choice where to save it or not...either way you will need to find the .ZIP file once downloaded.

When you have located the downloaded .ZIP file, you are ready for the next step.

Here are links to some of the other maps available - note that these maps are user generated, so each landing page may be a little different.

Canada - There is a link near the bottom of the page called "Direct Download"

USA - There is a link near the bottom of the page called "Direct Download"

Australia, New Zealand, Costa Rica, Mexico, Panama

Caribbean, Central America, South America, Southern Africa

UK and Ireland

Rest of the World

Step 5: UnZip the OpenStreetMap File

Hopefully you have now downloaded and located your OpenStreetMap .ZIP file! You will need it for the next steps.

Most operating systems these days have some version of the ZIP software installed by default. On a Windows computer, right clicking your mouse on the downloaded .ZIP file shows a menu that includes "Extract all...", which is the UnZip utility for windows.

Select "Extract All..." and click the Extract Button...the result is a folder that contains a gmapsupp.img file.

Once you have located the gmapsupp.img file, you are ready for the next step.

Thank you to Helen Edley of for the Mac screen shots and the editing!

Step 6: Copy the .img File Onto the Garmin Oregon 450 MicroSD Card

With your Garmin 450 in hand, gently open the waterproof rubber USB port cover. With the GPS
turned off, plug a USB cable into your computer and then into the USB port on the GPS. The Oregon will automatically start to power up in "Mass Storage" mode.

Open the microSD card folder and the Garmin Folder too. Copy the "gmapsupp.img" file into the Garmin folder.

NOTE: This file will not work if its on the Garmin GPS directly, or not in the Garmin folder. It needs to be on the microSD card and inside the Garmin folder.

Advanced User Note: Copying these files to the MicroSD card is fairly slow over the USB cable to the Garmin directly. For the fastest copy times, remove the microSD card and use a SD-card reader attached to your computer. Replace the microSD card in the Garmin Oregon when complete.

Step 7: Enable the OpenStreetMap on the Garmin Oregon 450

  1. Safely unplug your Garmin Oregon from your computer and press the power button to start up the GPS.
  2. Once it has started up, find the "Setup" button - it looks like a wrench.
  3. Press "Map".
  4. Press "Select Map".
  5. For each map, click on it and choose "Enable" or "Disable". Enable the OpenStreetMap, disable all the rest.

NOTE: Some maps can "Layer" meaning that multiple maps can be enabled and show features from both. OpenStreepMap files do layer, but for the purposes of this Instructable, its best to turn all the rest off until you are familiar with the process.

Step 8: Tips From Steve

My Geocaching geek friend Steve Roy suggests making two setting changes on the Garmin to make it easy to read in dense areas.

Go Settings-> Map->Advanced Map Setup and set Shaded Relief to "Do Not Show".


Go Settings-> Map->Advanced Map Setup-> Zoom Levels and set Land Cover to "Off".

The resulting image is a bit easier to read, yet has all the trails - Great tip, thanks Steve!

Step 9: Congratulations!

Yeah! Use the back buttons to return to the main screen of your Garmin Oregon and click on the "Map" button - you should see a highly detailed map of the area (unless of course you live in an area with not many details - but likely you will see more then you USED to have!).

Congratulations! You have installed an OpenStreetMap onto your Garmin Oregon 450!

Remember to update your map every month or so to assure you have the LATEST map details on your GPS. To update the map, follow the process from the beginning - download the ZIP file, UnZip it, Copy the file to your microSD card and assure the correct maps are enabled.