GETXprofile function

Cross sectional profile through a digital elevation map

Cross sectional profile through a digital elevation map

Example of how to use RPMG button functions. This example shows how to plot a DEM and interactively change the plot and find projected cross-sections through a surface.

GETXprofile(jx, jy, jz, LAB = "A", myloc = NULL, PLOT = FALSE, NEWDEV=TRUE, asp=1)

Arguments

  • jx, jy: locations of grid lines at which the values in 'jz' are measured.
  • jz: a matrix containing the values to be plotted
  • LAB: Alphanumeric (A-Z) for labeling a cross section
  • myloc: Out put of Locator function
  • PLOT: logical. Plot is created if TRUE
  • NEWDEV: logical. Plot is on a new device if TRUE
  • asp: aspect ration for plotting, see par

Details

The program uses a similar input format as image or contour, with structure from the locator() function of x and y coordinates that determine where the cross section is to be extracted.

Returns

Returns a list of x,z values representing the projected values along the cross section. - RX: distance along cross section

  • RZ: values extracted from the elevation map

Author(s)

Jonathan M. Leesjonathan.lees@unc.edu

Note

The program is an auxiliary program provided to illustrate the RPMG interactive R analysis.

See Also

locator, image

Examples

## Not run: ####### get data data(volcano) #### extract dimensions of image nx = dim(volcano)[1] ny = dim(volcano)[2] ### establish units of image jx = 10*seq(from=0, to=nx-1) jy = 10*seq(from=0, to=ny-1) #### set a letter for the cross section LAB = LETTERS[1] ### coordinates of cross section on image ### this is normally set by using the locator() function x1 = 76.47351 y1 = 231.89055 x2 = 739.99746 y2 = 464.08185 ## extract and plot cross section GETXprofile(jx, jy, volcano, myloc=list(x=c(x1, x2), y=c(y1, y2)), LAB=LAB, PLOT=TRUE) ## End(Not run)
  • Maintainer: Jonathan M. Lees
  • License: GPL (>= 2)
  • Last published: 2024-07-09

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