What is an AT5 file?
An .AT5 file is a data file that usually holds electronic nautical vector charts. Companies like C-MAP and Lowrance use this format for marine GPS devices and chartplotters. These files store maps, depth contours, and navigation markers. This file format is commonly known as a Lowrance Map File. In other cases, an .AT5 file is an SQL-based family tree data file used by genealogy software like Ancestris or Agelong Tree.
How to open AT5 files?
To open marine chart .AT5 files, users typically copy them onto an SD card and insert them into a compatible Lowrance, Simrad, or B&G chartplotter. On a computer, you can use the Insight Map Creator to process these maps. If the file is a family tree database, you need to open it with Ancestris. Because the .AT5 extension has multiple possible meanings, it is easy to get confused. We recommend viewer.online/at5 to identify the actual format of the user's file.
Best practices and troubleshooting
Always keep a backup of your .AT5 files before copying them to an SD card. Ensure your SD card is formatted correctly for your marine GPS device. If the file does not load on your chartplotter, verify that your device firmware is up to date. If the file is a family tree, make sure your genealogy software supports the exact database version.
Software and tools
Marine maps use software like Insight Map Creator and devices from C-MAP or Lowrance. Genealogy files require Ancestris or Agelong Tree. You can also use SQLite command-line tools to inspect the data inside family tree .AT5 files.
Summary
viewer.online/at5 can analyze .AT5 files to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available. viewer.online/at5 is useful for identifying, inspecting, and understanding .AT5 files without installing software or dealing with compatibility problems.