Using TOPO Mapping on the GPSMAP 620 or 640

Starting with software version 3.60, both the GPSMAP 620 and 640 are able to display TOPO  maps on both the Car and Boat modes. Please download and run Garmin Express in order to update the software on the GPSMAP 620 or 640.

Once the software is updated, the GPSMAP 640 is able to display TOPO maps on both Boat and Car modes, and the GPSMAP 620 is able to display TOPO maps on Boat mode. TOPO mapping can be used on the Car mode of the GPSMAP 620; however there are a few factors that need to be taken into consideration before the mapping will work on the device.

The issue is that the GPSMAP 620 is not preloaded with any detailed road mapping, so the Car mode is not accessible until the road mapping (City Navigator NT) is installed onto an SD card in the device.

The City Navigator NT and TOPO mapping programs have to be purchased on the DVD format (Discontinued) so they can be installed on a computer. Once both mapping products are installed on the computer, the area needed can be selected from both products and sent to the SD card that is inserted into the device. 

When both maps are installed on the SD card, the device can then be booted into the Car mode as the device now sees the City Navigator NT mapping installed.

Once in the Car mode, please follow these instructions to disable the City Navigator NT mapping which will allow the TOPO mapping to be displayed:

1. Press the Tools button in the lower right corner of the screen
2. Choose Settings
3. Choose Map
4. Press the Map Info button in the bottom middle of the screen
5. Touch the option for CN North America NT to uncheck the box to the left of it
6. Make sure TOPO still has a checkmark beside it
7. Press and hold the Back button for a few seconds to get back to the main screen

When viewing the map, the TOPO mapping will now appear. If the road mapping is needed at any time, simply follow the instructions above and turn on the City Navigator NT mapping.