Custom GPS Maps

I love using my Garmin GPS's with the mapping feature.

But even with the Mapsource maps, the coverage is lacking outside the US, UK, and Europe and outdated even in the US.

Example Captured from GPS screen, showing Cozumel, QR, Mexico

Americas Basemap:
Permanently installed in GPS
if purchased from a dealer in the Americas.

Shows the rough shape of the island
The International Airport
San Miguel (city) not by correct name
(covered by F3 waypoint)
Cedral small town

Worldmap Loaded:

Shape of the island is slightly better
A few streams added
All 3 light houses are shown
(W) means light house
Several water navigational lights (red or Green)
Only 2 roads show (as unpaved)
funny, 10 years ago these and a lot more roads were paved, not to mention a lot more unpaved roads

My Custom map Loaded:

Accurate detailed outline of the island
Mangrove North side of Island
Main Paved roads (runs across and around south and back to San Miguel and to the mangrove)
Many unpaved roads (looks like rail road ties)
Many residential streets in San Miguel
Airport shows both runways (CZM commercial, and Military)
100 Meter depth contour shown around the island.
Points Of Interest: Carlos n Charlie's (bar), a few Hotels, International Port, underwater Wreck

I created this Map while learning how to create them, and plan to add much more detail over time.

None of the data or images were used from any Garmin map product to create My Custom Map or upload to the GPS. Screen captures are shown for comparison only.

My Cozumel Marine Map

My Cozumel Topographic Map

The same map loaded in a COLOR GPS (GPS map 76cs)

Testing Accuracy of Maps

On my recent cruse to Cozumel & Calica I was able to use and test the custom maps.

Cozumel


The waypoints show that the map is correct, but 500 ft. too far north of actual positions.

Calica
At Calica the ship backed into port.
	Here the Dregged Deep Water Port is clearly seen on the GPS and in the Photos I took.	I have marked on the photo where the waypoints were taken, very accurate!

		The wandering track lines were made while I was doing extensive research, under the cover of a tent and GPS in a less than perfect position for satelite reception.