README.md

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YAPS - (Yet Another Positioning Solver)

Welcome to the yaps repository. The yaps package is based on the original YAPS presented in Baktoft, Gjelland, Økland & Thygesen (2017): Positioning of aquatic animals based on time-of-arrival and random walk models using YAPS (Yet Another Positioning Solver)

To use yaps on own data, you need to compile a TOA-matrix based on synchronized hydrophone data and replace the hydros dataframe with actual hydrophone positions. A complete step-by-step guide on how to do this, can be found in our pre-print paper Opening the black box of fish tracking using acoustic telemetry. The example in this guide is based on data collected using a 69 kHz PPM-based system (Vemco VR2). We are working towards adding examples based on data collected using other manufacturers.

Dependencies

The yaps package requires devtools and TMB. Please see instructions on TMB installation. If working on Windows, you might also need to install Rtools as specified in the TMB documentation.

Disclaimer

yaps obeys the fundamental rule of “garbage in, garbage out”. Therefore, DO NOT expect yaps to salvage a poorly designed study, nor to turn crappy data into gold. We have attempted to make both synchronization process and track estimation user-friendly. However, it is not trivial to synchronize hydrophones (let alone automating the process) based on detections in a variable and often noisy environment. Hydrophones might be replaced/shifted and if not fixed securely, hydrophones might move/be moved during a study. Additionally, hydrophone performance and output format varies considerably among (and within) manufacturers. On top of that, hydrophones don’t always behave and perform as expected. For instance, some hydrophone models autonomously initiate reboots causing perturbation of varying magnitude and/or duration of the internal clock at apparently random time intervals. Therefore, the functions in yaps might perform sub-optimal or even fail miserably when applied to new data. If/when this happens, please let us know through a direct message or leave a bug-report. Also note, the to-do list for improvements and tweaks is long and growing, so stay tuned for updates.

Installation

Make sure you have the newest version of yaps installed. Run install.packages('yaps') to get the latest version on CRAN.

Processing example data ssu1

The code below is based on the example workflow presented in Opening the black box of fish tracking using acoustic telemetry. See the pre-print for further explantion of parameters and workflow.

library(yaps)
set.seed(42) # Just to keep consistency in this example

# # # Example using the ssu1 data included in package. See ?ssu1 for info.
# # # Set parameters to use in the sync model - these will differ per study
max_epo_diff <- 120
min_hydros <- 2
time_keeper_idx <- 5
fixed_hydros_idx <- c(2:3, 6, 8, 11, 13:17)
n_offset_day <- 2
n_ss_day <- 2
keep_rate <- 20

# # # Get input data ready for getSyncModel()
inp_sync <- getInpSync(sync_dat=ssu1, max_epo_diff, min_hydros, time_keeper_idx, 
    fixed_hydros_idx, n_offset_day, n_ss_day, keep_rate=keep_rate, silent_check=TRUE)

# # # Check that inp_sync is ok
checkInpSync(inp_sync, silent_check=FALSE)

# # # Also take a look at coverage of the sync data
getSyncCoverage(inp_sync, plot=TRUE)

# # # Fit the sync model
sync_model <- getSyncModel(inp_sync, silent=TRUE, max_iter=200, tmb_smartsearch = TRUE)

# # # On some systems it might work better, if we disbale the smartsearch feature in TMB
# # # To do so, set tmb_smartsearch = FALSE in getSyncModel()

# # # Visualize the resulting sync model
plotSyncModelResids(sync_model, by = "overall")
plotSyncModelResids(sync_model, by = "quantiles")
plotSyncModelResids(sync_model, by = "sync_tag")
plotSyncModelResids(sync_model, by = "hydro")
plotSyncModelResids(sync_model, by = "temporal_hydro")
plotSyncModelResids(sync_model, by = "temporal_sync_tag")

# # # If the above plots show outliers, sync_model can be fine tuned by excluding these.
# # # Use fineTuneSyncModel() for this.
# # # This should typically be done sequentially using eps_thresholds of e.g. 1E4, 1E3, 1E2, 1E2
sync_model <- fineTuneSyncModel(sync_model, eps_threshold=1E3, silent=TRUE)
sync_model <- fineTuneSyncModel(sync_model, eps_threshold=1E2, silent=TRUE)

# # # Apply the sync_model to detections data.
detections_synced <- applySync(toa=ssu1$detections, hydros=ssu1$hydros, sync_model)

# # # Prepare data for running yaps
hydros_yaps <- data.table::data.table(sync_model$pl$TRUE_H)
colnames(hydros_yaps) <- c('hx','hy','hz')
focal_tag <- 15266
rbi_min <- 20
rbi_max <- 40
synced_dat <- detections_synced[tag == focal_tag]
toa <- getToaYaps(synced_dat=synced_dat, hydros=hydros_yaps, pingType='rbi', 
  rbi_min=rbi_min, rbi_max=rbi_max)
bbox <- getBbox(hydros_yaps, buffer=50, pen=1e6)
inp <- getInp(hydros_yaps, toa, E_dist="Mixture", n_ss=5, pingType="rbi", 
  sdInits=1, rbi_min=rbi_min, rbi_max=rbi_max, ss_data_what="est", ss_data=0, bbox=bbox)

# # # Check that inp is ok
checkInp(inp)

# # # Run yaps on the prepared data to estimate track
yaps_out <- runYaps(inp, silent=TRUE, tmb_smartsearch=TRUE, maxIter=5000) 

# # # Plot the results and compare to "the truth" obtained using gps

oldpar <- par(no.readonly = TRUE) 
par(mfrow=c(2,2))
plot(hy~hx, data=hydros_yaps, asp=1, xlab="UTM X", ylab="UTM Y", pch=20, col="green")
lines(utm_y~utm_x, data=ssu1$gps, col="blue", lwd=2)
lines(y~x, data=yaps_out$track, col="red")

plot(utm_x~ts, data=ssu1$gps, col="blue", type="l", lwd=2)
points(x~top, data=yaps_out$track, col="red")
lines(x~top, data=yaps_out$track, col="red")
lines(x-2*x_sd~top, data=yaps_out$track, col="red", lty=2)
lines(x+2*x_sd~top, data=yaps_out$track, col="red", lty=2)

plot(utm_y~ts, data=ssu1$gps, col="blue", type="l", lwd=2)
points(y~top, data=yaps_out$track, col="red")
lines(y~top, data=yaps_out$track, col="red")
lines(y-2*y_sd~top, data=yaps_out$track, col="red", lty=2)
lines(y+2*y_sd~top, data=yaps_out$track, col="red", lty=2)

plot(nobs~top, data=yaps_out$track, type="p", main="#detecting hydros per ping")
lines(caTools::runmean(nobs, k=10)~top, data=yaps_out$track, col="orange", lwd=2)
par(oldpar)

Example using YAPS on simulated data

rm(list=ls())   
library(yaps)

# Simulate true track of animal movement of n seconds
trueTrack <- simTrueTrack(model='crw', n = 15000, deltaTime=1, shape=1, scale=0.5, addDielPattern=TRUE, ss='rw')

# Simulate telemetry observations from true track.
# Format and parameters depend on type of transmitter burst interval (BI) - stable (sbi) or random (rbi).
pingType <- 'sbi'

if(pingType == 'sbi') { # stable BI
    sbi_mean <- 30; sbi_sd <- 1e-4;
    teleTrack <- simTelemetryTrack(trueTrack, pingType=pingType, sbi_mean=sbi_mean, sbi_sd=sbi_sd)
} else if(pingType == 'rbi'){ # random BI
    pingType <- 'rbi'; rbi_min <- 20; rbi_max <- 40;
    teleTrack <- simTelemetryTrack(trueTrack, pingType=pingType, rbi_min=rbi_min, rbi_max=rbi_max)
}

# Simulate hydrophone array
hydros <- simHydros(auto=TRUE, trueTrack=trueTrack)
toa_list <- simToa(teleTrack, hydros, pingType, sigmaToa=1e-4, pNA=0.25, pMP=0.01)
toa <- toa_list$toa

# Specify whether to use ss_data from measured water temperature (ss_data_what <- 'data') or to estimate ss in the model (ss_data_what <- 'est')
ss_data_what <- 'data'
if(ss_data_what == 'data') {ss_data <- teleTrack$ss} else {ss_data <- 0}


if(pingType == 'sbi'){
    inp <- getInp(hydros, toa, E_dist="Mixture", n_ss=10, pingType=pingType, sdInits=0, ss_data_what=ss_data_what, ss_data=ss_data)
} else if(pingType == 'rbi'){
    inp <- getInp(hydros, toa, E_dist="Mixture", n_ss=10, pingType=pingType, sdInits=0, rbi_min=rbi_min, rbi_max=rbi_max, ss_data_what=ss_data_what, ss_data=ss_data)
} 
str(inp)

yaps_out <- c()
maxIter <- ifelse(pingType=="sbi", 500, 5000)
yaps_out <- runTmb(inp, maxIter=maxIter, getPlsd=TRUE, getRep=TRUE)
str(yaps_out)

# Estimates in pl
pl <- yaps_out$pl
# Correcting for hydrophone centering
pl$X <- yaps_out$pl$X + inp$inp_params$Hx0
pl$Y <- yaps_out$pl$Y + inp$inp_params$Hy0


# Error estimates in plsd
plsd <- yaps_out$plsd

# plot the resulting estimated track and the true simulated track
par(mfrow=c(2,2))
plot(hy~hx, data=hydros, asp=1, xlab="UTM X", ylab="UTM Y", pch=20, col="green")
lines(y~x, data=trueTrack, col="blue", lwd=2)
lines(y~x, data=yaps_out$track, col="red")

plot(x~time, data=trueTrack, col="blue", type="l", lwd=2)
points(x~top, data=yaps_out$track, col="red")
lines(x~top, data=yaps_out$track, col="red")
lines(x-2*x_sd~top, data=yaps_out$track, col="red", lty=2)
lines(x+2*x_sd~top, data=yaps_out$track, col="red", lty=2)

plot(y~time, data=trueTrack, col="blue", type="l", lwd=2)
points(y~top, data=yaps_out$track, col="red")
lines(y~top, data=yaps_out$track, col="red")
lines(y-2*y_sd~top, data=yaps_out$track, col="red", lty=2)
lines(y+2*y_sd~top, data=yaps_out$track, col="red", lty=2)

plot(nobs~top, data=yaps_out$track, type="p", main="#detecting hydros per ping")
lines(caTools::runmean(nobs, k=10)~top, data=yaps_out$track, col="orange", lwd=2)

Papers using or relating to YAPS

2020

2019

2017



baktoft/yaps documentation built on April 18, 2021, 7:33 a.m.