zigzagSurvey: Generate a coordinate list for a zig-zag survey

In AustralianAntarcticDivision/EchoviewR: Control of Echoview via COM

Generate a coordinate list for a zig-zag survey

Description

The coordinate list is generated in degrees decimal degree format (dd.ddd), with Southern hemisphere denoted by negative numbers. Transect length are specified in km and bearings in degress where North 0 deg, East 90 deg, South 180 deg and West 270 deg.

Usage

zigzagSurvey(
  startLon,
  startLat,
  lineLengthkm,
  startBearingdeg,
  rotationdeg,
  numOfLines,
  proj4string = CRS("+proj=longlat +datum=WGS84"),
  unrotated = FALSE
)

Arguments

startLon	start longitude of survey.
startLat	start latitude of survey.
lineLengthkm	transect line length in km.
startBearingdeg	Bearing of each transect in degrees.
rotationdeg	rotation angle for entire survey pattern.
numOfLines	Number of transects.
proj4string	projection string of class CRS-class
unrotated	FALSE return rotated coordinates TRUE list of rotated and unrotated coordinates.

Value

Geographical coordinates of start and end of line positions. unrotated=TRUE list of rotated and unrotated coordinates

Author(s)

Martin Cox [e-mail]

See Also

zigzagSurvey

Examples

## Not run: 
coords=zigzagSurvey(startLon=-100,startLat=-60,lineLengthkm=2,
startBearingdeg=30,
rotationdeg=10,numOfLines=11)
plot(0,0,xlim=range(coords[,1]),ylim=range(coords[,2]),type='n',
xlab='Longitude, deg',ylab='Latitude, deg')
arrows(x0=coords[1:(nrow(coords)-1),1], y0=coords[1:(nrow(coords)-1),2], 
      x1 = coords[2:nrow(coords),1], y1 = coords[2:nrow(coords),2])
text(coords,row.names(coords),cex=0.6)
points(coords[1,1],coords[1,2],col='blue',pch=17,cex=2)
points(coords[nrow(coords),1],coords[nrow(coords),2],col='blue',pch=15,cex=2)
legend('topright',c('Beginning','End'),col='blue',pch=c(17,15))
#Use unrotated=TRUE and check coordinates in the- 
#-returned coordinate list object are identical:
coordL= zigzagSurvey(startLon=-100,startLat=-60,lineLengthkm=2,
startBearingdeg=30,
rotationdeg=0,numOfLines=11,unrotated=TRUE)
identical(coordL[[1]],coordL[[2]])
#display rotated and unrotated coordinates"
coordL= zigzagSurvey(startLon=-100,startLat=-60,lineLengthkm=2,
startBearingdeg=30,
rotationdeg=5,numOfLines=11,unrotated=TRUE) 
coords=coordL$unrotatedGeogs; coordsRotate=coordL$rotatedGeogs
plot(0,0,xlim=range(c(coords[,1],coordsRotate[,1])),
ylim=range(c(coords[,2],coordsRotate[,2])),type='n',
xlab='Longitude, deg',ylab='Latitude, deg')
arrows(x0=coords[1:(nrow(coords)-1),1], y0=coords[1:(nrow(coords)-1),2], 
      x1 = coords[2:nrow(coords),1], y1 = coords[2:nrow(coords),2])
arrows(x0=coordsRotate[1:(nrow(coordsRotate)-1),1], 
y0=coordsRotate[1:(nrow(coordsRotate)-1),2], 
      x1 = coordsRotate[2:nrow(coordsRotate),1], 
      y1 = coordsRotate[2:nrow(coordsRotate),2],col='blue')
legend('bottomleft',c('Unrotated','Rotated'),lty=1,col=c(1,'blue'))

## End(Not run)

AustralianAntarcticDivision/EchoviewR documentation built on Aug. 21, 2023, 6:56 p.m.