Lowrance USR — Lowrance marine GPS waypoint format: fishing electronics legacy

2026-06-2412 min read

LowranceUSRmarinefishingchartplotterwaypointnavigation

Export formats: LOWRANCE-USR

Lowrance USR is a binary file with a .usr extension saved to SD card from any modern chartplotter in the Lowrance HDS, Elite, or HOOK families. Inside are waypoints (marked spots), tracks (recorded paths), and routes (planned itineraries) — all with icon tags, notes, and timestamps. The name expands to "User Data Recording": the format exists precisely so an angler or yachtsman can take their data off the device, archive it, share it with a friend, or import it into third-party software. Outside the Lowrance ecosystem USR is perceived as a closed format, and the only practical work paths are gpsbabel or commercial Reef Master, because Lowrance Electronics — founded 1957 and still going — has never published an official specification.

Map generation of Istanbul city center — Old Istanbul, Eminönü district. The Bosphorus and Sea of Marmara are a classic marine-chartplotter zone. A route from the Galata Bridge to the Princes' Islands on a Lowrance HDS is saved in .usr together with waypoints for fishing spots.

History: Lowrance Electronics and chartplotter evolution

Lowrance Electronics was founded in 1957 in Tulsa, Oklahoma by brothers Darrell, Carl, and Arlen Lowrance — they released the first commercial transistorized sonar called "Little Green Box" in 1957 and made the brand synonymous with affordable fishing electronics. Since 1992 the company has belonged to Simrad-Lowrance Group, since 2007 to Navico (brands Lowrance, Simrad, B&G), and since 2021 Navico has been a division of Brunswick Corporation. All three brands inside Navico (Simrad for premium boaters, Lowrance for the mid-segment, B&G for sport yachtsmen) share a common software stack and file formats; USR originated specifically in Lowrance but Simrad and B&G later adopted it as an export format.

The .usr format itself appeared in the early 2000s on the Lowrance LMS and iFinder chartplotter series. The first version — USR v2 — was a simple linear dump of waypoints and tracks. Each new series added fields: USR v3 added routes, USR v4 — more icons and notes, USR v5 (around 2014) — extended waypoint metadata with photos and custom icons, USR v6 (around 2018) — integration with C-MAP cartography and Lowrance FishReveal sonar data. Modern chartplotters HDS Live, HDS Carbon, Elite FS, HOOK Reveal write USR v6 specifically, but for compatibility offer export to older v4/v5.

An important ecosystem milestone is Insight Genesis, Lowrance's cloud service for community generation of bottom bathymetry maps based on user sonar logs. The service launched in 2013, grew to millions of tracks, but in 2024 was shut down by Navico in favor of the successor C-MAP Genesis (same concept but inside the C-MAP ecosystem). All USR files previously uploaded to Insight Genesis now work only locally or through C-MAP Genesis.

In Russia USR format is known primarily by sea and large-water-body fishing enthusiasts on the Caspian, Baltic, and Black Seas, as well as on large freshwater reservoirs (Kuibyshev, Rybinsk, Seliger). Boats 5-9 meters with outboard motors are often equipped with Lowrance HOOK Reveal or Elite FS — the mid-price segment with structural echo-sounding support (StructureScan, DownScan). USR is the standard way to move fishing-spot waypoints between boat and computer.

Inside a USR file

Lowrance USR is a binary format, and no official specification is publicly available. Structure was reverse-engineered by the community: primary description work was done by the gpsbabel authors and the Lowrance USR Reader project, with further refinements added per file version.

In general terms the file begins with a 6-12 byte header containing magic bytes, format version (e.g., 06 00 00 00 for USR v6), and waypoint count. Then come data blocks:

Waypoint records — for each point: position (lat/lon in Lowrance-specific format — Mercator Meters relative to reference point, not standard degrees), name (UTF-16 string), description, icon ID (integer from 0 to hundreds — each value corresponds to a pre-defined icon: anchor, fish, lighthouse, "danger"), creation timestamp (POSIX seconds since 1970), color.
Trail records — recorded tracks. Structure — track header with name and metadata, then array of trail points (lat/lon + timestamp + depth/sonar data per point).
Route records — planned routes as a sequence of waypoint IDs with metadata.
Event records (USR v6+) — sonar data (FishReveal markers, bottom hardness samples) — for rendering in C-MAP Genesis.

Coordinates in Lowrance USR are stored not as familiar degrees but as 32-bit integer Mercator meters in WGS84 projection. Conversion formula: latitude = (arctan(exp(y / 6378137)) - π/4) × 2 × 180/π where y is the file value. This gives about 1 meter accuracy at the equator and about 50 cm at latitude 60°. Programs like gpsbabel handle conversion automatically, but if you're parsing USR by hand — account for this.

Endianness is little-endian (as on x86). Waypoint record size varies: in USR v4 about 100 bytes per point, in USR v6 up to 300 bytes with extended metadata. A typical file with one hundred waypoints and three tracks takes 30-100 KB. The maximum waypoint count is theoretically unbounded, but in practice chartplotters cap around 5000-10000 points.

Who needs Lowrance USR: five roles

Angler with a marine boat. The main audience. Season after season accumulates fishing-spot waypoints — pike ledges, perch schools, walleye holes. Every season makes a .usr backup to SD card to avoid losing years of observations if the device fails or is upgraded. Also used for sharing coordinates with friends: SD card travels to a buddy, gets imported into his chartplotter.

Yachtsman with navigation routes. If you sail the Black Sea or Baltic on a typical Gelendzhik → Tuapse → Sochi or Kaliningrad → Gdansk route, your USR file holds routes with waypoints at bay-of-entry, anchorages, marina locations. This is a base you drag between seasons and between boats.

Fishing-guide instructor. A professional fishing guide shows clients "their" spots without giving them away verbatim. USR with the right export (only tracks without waypoints, or only specific waypoints) — a way to give the client minimum data so they don't get lost while preserving commercial secrets.

Bathymetry cartographer. For C-MAP Genesis and Reef Master USR is the primary input format. A guide or enthusiast spends many hours over a reservoir with an echosounder, recording sonar data, then uploads USR to the computer and through C-MAP Genesis creates a detailed bottom-depth map for the region. These maps are then available to other C-MAP subscribers.

Rescue/maritime service. In a maritime rescue setting Lowrance chartplotters aboard rescue boats store coordinates of typical emergency landmarks (banks, reefs, shoals) as standard waypoints in USR. Updates are distributed centrally — a single .usr file with updated hazard points is copied to all flotilla boats.

Software for USR: seven tools

Lowrance HDS / Elite / HOOK chartplotter. The device itself. Main USR consumer and producer. SD card slot, export via User Data → Export menu. Device price — from $300 (HOOK Reveal 5") to $5000 (HDS Live 16"). lowrance.com

gpsbabel. Open-source CLI utility for converting between track and waypoint formats. Supports USR read and write (via -i lowranceusr/-o lowranceusr), versions v2-v6. Cross-platform, free. The main tool for exchanging with other ecosystems (GPX, KML, Garmin GDB, FIT). gpsbabel.org

C-MAP Genesis. Navico's cloud service for community-generated detailed bottom maps based on user sonar logs. Successor to Insight Genesis (closed 2024). Upload USR with echo-sounding points — get a personal bathymetric map for the region, available on any C-MAP cards. c-map.com

Reef Master. Australian commercial software for developing custom bathymetric maps and processing sonar logs. Reads USR, .sl3 (Lowrance sonar log), Humminbird .dat, supports many export formats (KML, GeoTIFF, ESRI shapefile). Paid (~$200) but widely used among serious bathymetry cartographers. reefmaster.com.au

OpenCPN with Lowrance plugin. Open chart plotter for PC and Mac. A community plugin supports USR reading in view mode. Not as complete as gpsbabel but convenient when you need to show waypoints on a chart without conversion. Free. opencpn.org

Lowrance USR Reader (community). Community web tools and scripts for parsing USR. GitHub projects like lowrance-usr-parser or usr-to-gpx — simple Python scripts that read waypoints and tracks into JSON. Useful when automating processing without dependency on the gpsbabel binary.

Humminbird/Garmin interop via GPX. If you run multiple boats with different sonar brands, the only reliable exchange path is exporting each via its native software (gpsbabel for Lowrance, Humminbird PC for Helix, Garmin BaseCamp for echoMAP), then merging GPX, then importing back. USR is never understood directly by other manufacturers.

Pitfalls and tips

USR version matters. A Lowrance HOOK 2014-vintage cannot read USR v6 exported from HDS Live 2024. If you're passing a file to a colleague with an older device — export specifically USR v4 or v5 through User Data → Export → Format. By default gpsbabel writes v6 during conversion to USR — for backward compatibility use -o lowranceusr,wversion=4.

Map generation of Dubai city center — Dubai Marina. The Persian Gulf is a growing Lowrance market in the GCC region. Yachtsmen save routes from Marina to Palm Jumeirah and World Islands as routes in USR files.

Icons get renamed. Each waypoint in USR has an icon ID — an integer. Lowrance HDS supports about 200 predefined icons (anchor, fish of various types, lighthouse, danger, marina, fuel station, etc.). Garmin or Humminbird, after a GPX round-trip, lose exact correspondence — a "judging fish" icon in Lowrance becomes "default fish" in Garmin. If icons matter to your workflow — keep data only in native USR.

Tracks trim by device limits. A chartplotter holds tracks in a ring buffer: HDS Live — 100000 points per track, Elite FS — 50000, HOOK Reveal — 25000. During extended sailing old track points are simply overwritten. If you want to archive a full circumnavigation — offload USR to SD card more often than the device cycles the buffer.

Depth data in trails — for C-MAP Genesis only. In USR v6 each trail point can hold bottom depth (FishReveal sonar reading). This information is valid only for bathymetric-map generation in C-MAP Genesis or Reef Master. If you convert USR → GPX via gpsbabel, the depth field is lost (standard GPX has no such attribute). For sonar-data portability use Lowrance's native .sl3 format, not USR.

SD card must be FAT32 32 GB max. Lowrance HDS accepts SD up to 32 GB Class 10 formatted as FAT32. A 64 GB exFAT card (typical of modern cameras) often isn't recognized by the device or works unreliably. If the SD doesn't read — reformat to FAT32 via PC (Windows format /FS:FAT32 or Mac Disk Utility).

Coordinates in Mercator, not WGS84 degrees. When writing your own USR parser remember: lat/lon in the file are integer Mercator meters, not decimal degrees. Reading directly as float yields nonsense. Use gpsbabel, or a community parser, or implement the conversion formula above.

Insight Genesis is gone. If your 2018-2022 device manual mentions Insight Genesis for cloud upload — note that the service was shut down in 2024. The new service is C-MAP Genesis, works similarly but requires separate registration. Already-uploaded maps to Insight Genesis were transferred automatically only for C-MAP subscribers.

Using Lowrance USR in an osm2cdr.ru workflow

osm2cdr.ru exports vector and raster OSM maps, which USR-chartplotters can't accept directly — Lowrance takes only proprietary C-MAP/Navionics maps. But waypoints and routes can be moved both ways through a GPX intermediate.

Scenario 1: route on osm2cdr → Lowrance. You're planning a port-of-call or sailing trip in unfamiliar waters. On osm2cdr.ru you outline the coastline, export to GPX (waypoints for anchorages and marinas, route line for the main trajectory). On the computer you convert GPX → USR via gpsbabel:

gpsbabel -i gpx -f route.gpx -o lowranceusr,wversion=5 -F route.usr

Copy route.usr to the SD card in a folder typically named Lowrance or Navionics. Insert into the chartplotter, go to User Data → Import, pick the file. Waypoints and routes appear on screen, ready for navigation.

Scenario 2: fishing waypoints Lowrance → QGIS analysis. Over a season you've accumulated 200 fishing-spot waypoints. You want to analyze them spatially: do they correlate with depths, terrain, bottom type, coastline from OSM. You export USR from the device, convert to GPX:

gpsbabel -i lowranceusr -f fishing_spots.usr -o gpx -F spots.gpx

Open spots.gpx in QGIS as a vector layer. Overlay the coastline and water bodies from osm2cdr.ru (e.g., a water-area export as SHP or GeoPackage). Spatial join shows which waypoints sit in which OSM water objects: bays, banks, headlands.

Scenario 3: backup and archive via GPX standard. USR lives inside the Lowrance ecosystem. If in 10 years you want to retrieve your data — a USR v6 written today may not be readable by a chartplotter of 2036. Therefore an annual backup: USR → GPX via gpsbabel → cloud storage. GPX is open XML, readable by hundreds of programs, indestructible.

# annual backup
gpsbabel -i lowranceusr -f season-2026.usr -o gpx -F season-2026.gpx

Map generation of Rome city center — Rome center. Although Rome sits 30 km from the Tyrrhenian Sea, the nearest port Civitavecchia is the departure point for cruise and sailing yachts across the Mediterranean. A Lowrance HDS aboard a charter yacht here will show routes from Civitavecchia to Sardinia and back inside a USR file.

Sources

Lowrance Electronics (Navico/Brunswick) — lowrance.com
GPSBabel Lowrance USR format support — gpsbabel.org/htmldoc-development/fmt_lowranceusr.html
C-MAP Genesis bathymetry service — c-map.com/genesis
Reef Master software — reefmaster.com.au
OpenCPN open chart plotter — opencpn.org
Lowrance HDS / Elite / HOOK product line — lowrance.com/products