Satellite Overlay

Man’s best friend. Yes, offline satellite images are a necessity for navigating sparsely populated areas. The quality of commercial and open source chart material is inaccurate.

I will explain the use of OpenCPN with a satellite overlay on a Windows laptop. There is a 5-minute video on YouTube from Sailing LuckyFish, ep 113 which explains it all.

Fortunately, we have a B&G chartplotter that can read AT5 formats. So I will describe that more complicated routine as well


The only platform which works, with all plugins, map provider and basic software, is Windows. I forced my laptop to stay on W10 because I am not sure you can work offline on W11.

  • Windows laptop, Chrome browser, Google Translate extension, USB card reader;
  • A SD Card of 32 Gb, formatted as FAT32 device;
  • Use SAS Planet to access and store satellite images from different providers locally;
  • Use OpenCPN with charts of the specific area;
  • Insight Map Creator, a program to convert the images to AT5 map material;
  • Use the offline satellite images as AT5 cards on your B&G Zeus3;
  • During the preparation you need internet, at sea everything is available offline.

SAS Planet

SAS Planet is only available for Windows. Go to The site is in Russian, choose to translate webpage to your own language and download the zip file. You need two downloads the first time. First the latest stable version and a few rows down on the screen the full set of cards.

The program does not have an installer, you extract the zip file in your own chosen directory. Second extract the to SASPlanet directory and get started. My current version is 201212.

Insight Map Creator

A free program from Navico, but it is increasingly difficult to find a version of this software. There is a deep link available that provides a download for Windows,

At 16:38 this video demonstrate the use of Insight Map Creator (AT5)

Preparations and circumnavigation of a Seawind 1260