04 Grid data

Data and information, data types, object types

Reading and managing grid data

Ground radar data is less often just one simple line. A ground radar survey can contain multiple single lines, connected to each other or taken in a raster pattern. First all the lines need to “marry” into one grid object.

#load in multiple lines
LINES <- file.path(paste0("FILE____", sprintf("%03d", 1:46), ".DZT"))

#create a new grid object out of all the lines
grid <- GPRsurvey(LINES, verbose = FALSE)
grid

plot(grid, asp = 1) 

Before calibrating the data from the survey, all the data needs to be in the right place and adjusted.

#reverse lines
grid <- reverse(grid, id = seq(from = 2, to = 11, by = 2))

#all the even GPR lines are reversed
grid <- reverse(grid, id = "zigzag")

There is two kinds of coordinates for a grid of radar data. The GPS coordinates, locating the survey plot in space and the coordinates defining how the lines are taken during the survey process.

#default example
setGridCoord(grid) <- list(xlines = seq_along(grid),
                         xpos   = seq(0,
                                      by = 0.2,
                                      length.out = length(grid)),
                         ylines = NULL,
                         ypos   = NULL)

#plotgrid
plot(grid, asp = TRUE)

Shifting individual lines

#shift line
grid2 <- tpShift(grid, 3, dx = 0.1, dy = 0.5)
plot(grid2)

# plot one line from the grid object
plot(grid[[1]])