Maps should be the same if you are viewing the same maps
~ Captain Paul's response to: ~ Big Moroo~
Thanks for the kind words. It is my goal to try and assist our readers to understand and use their GPS equipment for their many fishing and hunting endeavors.
As for your question, the Garmin GPSMap 541 comes loaded with Garmin “Coastal Maps” and the GPSMAP 421 does NOT come with preloaded maps. Both units can accommodate the Garmin Blue Chart g2 and the Blue Chart g2 Vision via a memory card that is inserted in the Secure Digital (SD) card slot.
Many manufactures to avoid sticker shock on the total price only include a basemap in their units. This map at least gets their customers out and using their units. However the base map is what the name implies, a basic map. This basic map may cover the entire U.S. coastline. These base maps do not show the detail that their accessory maps have. Base maps do not usually show the many small bayous, rivers, lagoons, lakes and canals that make up the coastal Louisiana marches.
Ultimately their customers upgrade their mapping by purchasing one of the many outstanding maps that are available for the units. Garmin’s top map at this time is their Blue Chart g2 and their BlueChart g2 Vision. The g2 Vision includes corrected aerial images that can be viewed as a map in some of their units. I believe that both of the units you listed can use the BlueChart g2 and g2 Vision mapping offered by Garmin.
So, if one unit has only Coastal Maps and the other has a BlueChart g2 or g2 Vision program installed in the SD card slot, they obviously will not display the same map images on the two separate units, However with the both having the same g2 program, the images would be NEARLY the same.
I say nearly because the GPSMAP 541 has a 5.0 inch diagonal screen with 234x320 pixels and the GPSMAP 421 has a 4.0 inch diagonal screen with 240x320 pixels. That means that the smaller unit will have more pixels and would produce smoother images on its screen. Most users would not even notice the difference, but there is a difference.
So the bottom line is if they both have the same map program installed, they should display nearly an identical image of the maps.
The BlueChart g2 and g2 Vision are sold by regions. One g2 Vision Region covers from Mobile Bay to Lake Charles and lists for $321.42. You can check it out at the Garmin web site at https://my.garmin.com/mapCoverage/coverage.faces?line=BlueChart+G2+Vision+Cards&country=en_US
A standard g2 chart covers all of the US and lists for about $160.70 from the Garmin web site at https://my.garmin.com/mapCoverage/coverage.faces?country=en_US