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Open SL2 Files on a Mac (No Windows Needed) (Beta)

View Lowrance sonar logs on a Mac, an iPad or a Chromebook: upload the .sl2 or .sl3 file and get the sonar pictures.

Opens: SL2, SL3, SLG
Saves: JPEG, PNG, GPX, KML, CSV

Open

Sonar log
Choose a file… or drop it here
.sl2, .sl3, .slg · up to 200 MB
    Replace file

    The .sl2, .sl3 or .slg file the fish finder recorded, copied from its memory card. One log at a time.

    Options
    Colours

    How echo strength is shown, from weak to strong.

    Units

    Automatic uses feet and miles for logs recorded in or near the United States, and metres elsewhere.

    More options
    Picture format

    JPEG pictures are several times smaller; PNG keeps every pixel exactly.

    Contrast

    Automatic stretches each channel's echo strengths over the whole colour scale, so faint fish and structure show. “As recorded” draws the values the unit stored.

    More pings per pixel give shorter pictures and fewer of them; each pixel keeps the strongest echo of its pings. Very long logs are combined anyway, so that each channel fits into 24 pictures.

    Your files are deleted after processing.

    Most programs that open Lowrance sonar logs on a computer run only on Windows. On a Mac you don't need them, nor a Windows virtual machine: this page reads .sl2, .sl3 and .slg logs in Safari, Chrome or Firefox and gives you the sonar pictures and data as ordinary files.

    On a Mac

    1. Put the fish finder's memory card into the Mac's card slot or a USB card reader. It appears in Finder like a USB stick.
    2. Find the log (for example Sonar0001.sl2) and drag it onto the upload box on this page, or copy it to your Mac first.
    3. Press Open. The pictures are JPEG files that open in Preview and Photos; the GPX track opens in most mapping apps, and the CSV in Numbers or Excel.

    On an iPad, iPhone or Chromebook

    The same works on an iPad or iPhone with a card reader: the card shows up in the Files app, and the upload box can pick the log from there. On a Chromebook the card appears in the Files app too.

    What you get

    • Sonar pictures of the 2D sonar, down scan and side scan in the log, with depth, time and distance marks.
    • A GPX track with the depth and water temperature at every point, and a KML file for Google Earth.
    • A depth map, and a CSV file with every ping for your own charts.

    Pitfalls

    • Eject the card before pulling it out. A log copied while the Mac was still writing to the card, or one the unit was writing when it lost power, can end in the middle of a ping. That last ping is skipped and the rest is read.
    • Large logs. Side-scan logs can reach hundreds of megabytes. They are read as a stream, so size is rarely a problem, but a slow connection makes the upload the longest part.
    • The right file. .usr and .adm files on the same card hold waypoints, routes and trails, not sonar. Upload the .sl2, .sl3 or .slg file.

    More about what this tool reads and writes: Sonar Log Viewer.

    More with Sonar Log Viewer