arabia

Tools to Read ‘Lowrance’ Binary Track Files

Description

Lowrance’ (http://www.lowrance.com/) chart plotters use an ugly but straightforward binary format to encode their tracks. Tools are provided to read ‘SL2’ files (and, very likely ‘SLG’ and ‘SL3’ files, too).

What’s Inside The Tin

The following functions are implemented:

• read_sl2: Read Lowrance binary track files
• read_sl2_cpp: A “No Frills” Faster Version in C++ (uncomment things in the package if you want this as the OP was having issues on Windows with Rtools) — look in old-source for the CPP version

Installation

devtools::install_git("https://gitlab.com/hrbrmstr/arabia")

Usage

library(arabia)
library(tidyverse)

# current verison
packageVersion("arabia")

## [1] '0.1.0'

Give it a go

system.time(xdf <- read_sl2(system.file("exdat", "example.sl2", package="arabia")))

## Format: sl2

## Block size: downscan

## .............

##    user  system elapsed 
##   2.263   0.047   2.411

xdf

## # A tibble: 1,308 x 22
##    channel   upperLimit lowerLimit frequency waterDepth keelDepth speedGps temperature lng_enc lat_enc speedWater track
##    <chr>          <dbl>      <dbl> <chr>          <dbl>     <dbl>    <dbl>       <dbl>   <int>   <int>      <dbl> <dbl>
##  1 Secondary         0.       13.3 200 KHz         2.62     0.328    0.500        15.8 4433307 7003054      0.500  4.97
##  2 DSI (Dow…         0.       13.4 200 KHz         2.62     0.328    0.500        15.8 4433307 7003054      0.500  4.97
##  3 Primary           0.       13.3 200 KHz         2.62     0.328    0.500        15.9 4433307 7003054      0.500  4.97
##  4 Secondary         0.       13.3 200 KHz         2.62     0.328    0.500        15.9 4433307 7003054      0.500  4.97
##  5 DSI (Dow…         0.       13.4 200 KHz         2.59     0.328    0.           15.8 4433307 7003054      0.     4.97
##  6 Secondary         0.       13.3 200 KHz         2.59     0.328    0.           15.8 4433307 7003054      0.     4.97
##  7 Secondary         0.       13.3 200 KHz         2.52     0.328    0.           15.9 4433307 7003054      0.     4.97
##  8 DSI (Dow…         0.       13.4 200 KHz         2.52     0.328    0.           15.9 4433307 7003054      0.     4.97
##  9 Primary           0.       13.3 200 KHz         2.52     0.328    0.           15.8 4433307 7003054      0.     4.97
## 10 DSI (Dow…         0.       13.4 200 KHz         2.52     0.328    0.           15.8 4433307 7003054      0.     4.97
## # ... with 1,298 more rows, and 10 more variables: altitude <dbl>, heading <dbl>, timeOffset <int>, headingValid <lgl>,
## #   altitudeValid <lgl>, gpsSpeedValid <lgl>, waterTempValid <lgl>, positionValid <lgl>, waterSpeedValid <lgl>,
## #   trackValid <lgl>

glimpse(xdf)

## Observations: 1,308
## Variables: 22
## $ channel         <chr> "Secondary", "DSI (Downscan)", "Primary", "Secondary", "DSI (Downscan)", "Secondary", "Seco...
## $ upperLimit      <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0...
## $ lowerLimit      <dbl> 13.3, 13.4, 13.3, 13.3, 13.4, 13.3, 13.3, 13.4, 13.3, 13.4, 13.3, 13.4, 13.3, 13.4, 13.3, 1...
## $ frequency       <chr> "200 KHz", "200 KHz", "200 KHz", "200 KHz", "200 KHz", "200 KHz", "200 KHz", "200 KHz", "20...
## $ waterDepth      <dbl> 2.620, 2.620, 2.620, 2.620, 2.586, 2.586, 2.516, 2.516, 2.516, 2.516, 2.516, 2.516, 2.516, ...
## $ keelDepth       <dbl> 0.328084, 0.328084, 0.328084, 0.328084, 0.328084, 0.328084, 0.328084, 0.328084, 0.328084, 0...
## $ speedGps        <dbl> 0.5, 0.5, 0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0...
## $ temperature     <dbl> 15.84112, 15.84112, 15.86293, 15.86293, 15.79128, 15.79128, 15.86293, 15.86293, 15.81620, 1...
## $ lng_enc         <int> 4433307, 4433307, 4433307, 4433307, 4433307, 4433307, 4433307, 4433307, 4433307, 4433307, 4...
## $ lat_enc         <int> 7003054, 7003054, 7003054, 7003054, 7003054, 7003054, 7003054, 7003054, 7003054, 7003054, 7...
## $ speedWater      <dbl> 0.5, 0.5, 0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0...
## $ track           <dbl> 4.974188, 4.974188, 4.974188, 4.974188, 4.974188, 4.974188, 4.974188, 4.974188, 4.974188, 4...
## $ altitude        <dbl> 324.7375, 324.7375, 324.7375, 324.7375, 324.8687, 324.8687, 324.8687, 324.8687, 324.8687, 3...
## $ heading         <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0...
## $ timeOffset      <int> 1317703, 1317706, 1318036, 1318905, 1318946, 1318982, 1319130, 1319140, 1319216, 1319222, 1...
## $ headingValid    <lgl> FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, ...
## $ altitudeValid   <lgl> TRUE, FALSE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, FALSE, FALSE, FAL...
## $ gpsSpeedValid   <lgl> TRUE, FALSE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, FALSE, FALSE, FAL...
## $ waterTempValid  <lgl> FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, ...
## $ positionValid   <lgl> FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, ...
## $ waterSpeedValid <lgl> FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, ...
## $ trackValid      <lgl> FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, ...