NMEA Viewer & Analyzer Online

Open an NMEA log in your browser and inspect what each message means. The viewer handles common NMEA 0183 sentences, AIS AIVDM/AIVDO messages and text exports of NMEA 2000 PGN/CAN frames. See fields, coordinates, source addresses, raw bytes and checksum results without uploading the log.

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Click to upload or drag & drop an NMEA log here

Accepts .nmea, .log and .txt text logs. NMEA 0183, AIS, Actisense/CANboat, SeaSmart, MiniPlex and common CAN dump lines are processed locally.

Waiting for a log. Load the sample to see all three protocol families at once.

Supported NMEA message families

Family	What is shown	Common input examples
NMEA 0183	Sentence type, talker ID, time, coordinates, speed, course, altitude and checksum	`RMC`, `GGA`, `GLL`, `VTG`, `WPL`, `ZDA`
AIS NMEA	Message type, MMSI, vessel data, position, speed and course; multipart messages are reassembled	`!AIVDM`, `!AIVDO`
NMEA 2000	PGN description, priority, source/destination, CAN ID, raw bytes and common navigation fields	Actisense PLAIN, CANboat, `$PCDIN`, `$MXPGN`, candump and YDWG-style text

NMEA 2000 is a protocol with PGNs, not one universal filename. This viewer accepts common text exports and captures. Unknown or manufacturer-specific PGNs remain visible with raw payloads rather than being silently discarded.

Use the NMEA viewer to troubleshoot a log

Load the log or paste a few lines.
Filter by protocol, search for a sentence or PGN, and enable mapped positions only when you need the navigation records.
Inspect decoded fields, source addresses, CAN bytes and checksum status in the table.
Use the map and position playback to check whether a recorded track is continuous or whether several sources were mixed together.

NMEA 0183, NMEA 2000 and AIS in one browser tool

NMEA 0183 uses readable comma-separated sentences such as $GPRMC. NMEA 2000 uses CAN frames and PGN numbers, so the same log can contain GPS, heading, depth, wind and electrical data. AIS uses NMEA 0183-style !AIVDM or !AIVDO payloads to describe vessels. The viewer keeps these families identifiable instead of flattening them into one generic table.

Parsing is local. There is no account, server upload or live hardware connection required. For a map-first workflow with KML, GPX and standalone HTML export, use NMEA to HTML Map.

FAQ

Is this an online NMEA parser?

Yes. It parses common NMEA text in the browser, without sending your file to a server. It shows both decoded values and the original raw lines.

Can it view NMEA 2000 PGNs?

Yes, for common text representations of NMEA 2000 frames: Actisense/CANboat PLAIN, SeaSmart PCDIN, MiniPlex MXPGN, YDWG-style raw lines and common candump forms. Common navigation PGNs such as position, COG/SOG, heading and GNSS data are decoded; unknown PGNs retain their raw bytes.

Does it support NMEA 2000 binary logs?

There is no single universal NMEA 2000 binary file format. This page intentionally accepts text exports and captures that can be identified in the browser rather than claiming every recorder-specific binary format.

Can I view an NMEA file without installing software?

Yes. Drop a text log into the page. The table and map work in a current browser, and the parsed rows can be downloaded as CSV.

Why is a checksum shown as “not supplied”?

Some NMEA sources omit the optional sentence checksum, while others include it after an asterisk. “Not supplied” is different from “invalid”; the viewer marks a supplied checksum as bad only when the calculated XOR does not match.